A systematic revision of Tatia (Siluriformes: Auchenipteridae: Centromochlinae)

495 Neotropical Ichthyology, 6(3):495-542, 2008 Copyright © 2008 Sociedade Brasileira de Ictiologia A systematic revision of Tatia (Siluriformes: Auchenipteridae: Centromochlinae) Luisa Maria Sarmento-Soares1,2 and Ronaldo Fernando Martins-Pinheiro2 The auchenipterid catfish genus Tatia is revised. Twelve species are recognized including three described as new. Tatia is diagnosed by the hyomandibula elongated anterodorsally, the anal-fin base of adult males reduced in length, and the caudal peduncle laterally compressed and deep with a middorsal keel. Tatia aulopygia occurs in the Madeira river drainage and is distinguished by the reduced cranial fontanel in adults and male modified anal fin with middle rays reduced in length. Tatia boemia, known from the upper Uruguay river drainage, is distinguished by its unique color pattern with dark chromatophores on the sides of body. Tatia brunnea from river basins in Suriname and French Guiana and the Negro river drainage, Amazon basin, is recognized by its wide head and mouth and by the male modified anal fin with sharply pointed tip. Tatia dunni, from the upper Amazon basin, is recognized by its narrow head, long postcleithral process in some specimens, and body coloration with irregular blotches or stripes. Tatia galaxias, endemic to the Orinoco river basin, is distinguished by its large eye and short snout. Tatia gyrina, distributed in the upper and central Amazon basin and in northern Suriname, has a uniquely reduced mesethmoid, slightly protruding lower jaw, second nuchal plate with slightly concave lateral borders, third nuchal plate reduced, small prevomer, low number of ribs, low number of vertebrae and sexual dimorphism regarding intumescent male genital papilla. Tatia intermedia, recorded from central and lower Amazon basin, Tocantins river, and coastal drainages in Guyana, Suriname, French Guiana, and eastern Pará State, Brazil, is distinguished by the short postcleithral process, small eye and long snout. Tatia neivai, from the upper Paraná river, Paraguay river and upper Paraíba do Sul river basin, is distinguished by its unique vertebral count and caudal-fin coloration consisting of transverse dark bars. Tatia strigata, from central Amazon basin and Negro river, is distinguished by its horizontally striped color pattern and the modified male anal fin with middle rays reduced in length. Tatia caxiuanensis, a new species described from the Curuá river, lower Amazon basin, is recognized by its wide cranial fontanel and distinctive anal fin in mature males. Tatia meesi, a new species described from the Essequibo river basin, Guyana, is distinguished from congeners by the cranial fontanel with two separate openings and thin nasal bone. Tatia nigra, a new species described from the central Amazon basin, is distinguished by its short postcleithral process, low number of vertebrae, and dark color pattern. All twelve species of Tatia are described or redescribed and a key to species is provided. O gênero Tatia de auquenipterídeos é revisado. Doze espécies são reconhecidas incluindo três descritas como novas. Tatia é reconhecido pelo hiomandibular fortemente fendido anterodorsalmente, base da nadadeira anal de machos maduros reduzida em tamanho, e pelo pedúnculo caudal lateralmente comprimido e alto com uma quilha médio-dorsal. Tatia aulopygia ocorre na drenagem do rio Madeira e é distinguida pela fontanela craniana reduzida em adultos e pela nadadeira anal em machos maduros fendida, pela redução em tamanho dos raios medianos. Tatia boemia, conhecida da drenagem do alto rio Uruguai, é reconhecida por seu padrão de colorido único com cromatóforos escuros pelas laterais do corpo. Tatia brunnea, de bacias hidrográficas no Suriname e Guiana Francesa e ainda da drenagem do rio Negro na Amazônia, é reconhecida pela ampla largura da cabeça e boca e pela nadadeira anal modificada em machos com extremidade pontiaguda. Tatia dunni, do alto Amazonas, é reconhecida pela cabeça estreita, pelo processo pós-cleitral longo em alguns espécimens, e pela coloração do corpo com manchas irregulares ou faixas claras. Tatia galaxias, endêmica da bacia do rio Orinoco, é distinguida pelos grandes olhos e focinho curto. Tatia gyrina, com ocorrência pelo alto e médio Amazonas, e pelos rios do norte do Suriname, possui mesetmóide reduzido, mandíbula levemente prognata, segunda placa nucal com bordo lateral estreito, terceira placa nucal reduzida, pré-vomer pequeno, reduzido número de costelas, pequeno número de vértebras e dimorfismo sexual onde a papila genital masculina é entumescida. Tatia 1Laboratório de Ecologia de Peixes, sala 525, Pavilhão Haroldo Lisboa, Departamento de Ecologia, Instituto de Biologia Roberto Alcântara Gomes, Universidade Estadual do Rio de Janeiro. Av. São Francisco Xavier, 524; Maracanã, 20550-013 Rio de Janeiro, RJ, Brazil. [email protected] 2Museu de Biologia Prof. Mello Leitão, Laboratório de Zoologia. Av. José Ruschi, 4, Centro, 29650-000 Santa Teresa, ES, Brazil. [email protected] A systematic revision of Tatia 496 intermedia é registrada para o médio e baixo rio Amazonas, rio Tocantins e ainda para drenagens costeiras na Guiana, Suriname, Guiana Francesa e leste do Pará no Brasil. É distinguida pelo processo do pós-cleitro curto, olhos pequenos e focinho longo. Tatia neivai, do alto rio Paraná, rio Paraguai e alto rio Paraíba do Sul, é distinguida pela contagem vertebral exclusiva e pela coloração da nadadeira caudal com barras transversais escuras. Tatia strigata, distribuída pelo médio Amazonas e rio Negro é reconhecida pelo padrão de colorido com listras horizontais irregulares e nadadeira anal modificada fendida em machos, com raios medianos reduzidos em tamanho. Tatia caxiuanensis, nova espécie, descrita para o rio Curuá no baixo Amazonas, é reconhecida pela fontanela craniana ampla e pela nadadeira anal de machos maduros distinta. Tatia meesi, nova espécie, descrita para o rio Essequibo, Guiana, é diferenciada de seus congêneres pela fontanela craniana com duas aberturas separadas e pelo osso nasal afilado. Tatia nigra, nova espécie, descrita para o médio Amazonas, é distinguida pelo processo pós-cleitral curto, pelo número reduzido de vértebras e pelo padrão de colorido escurecido. Todas as doze espécies de Tatia são redescritas ou descritas e uma chave de identificação é fornecida. Key words: South America, Freshwater, Catfish, Taxonomy, Centromochlus. Introduction The subfamily Centromochlinae comprises small to medium size auchenipterid catfishes that share derived anal-fin morphology in males (Ferraris, 1988; Soares-Porto, 1998). Four genera, Centromochlus,Tatia,Glanidium, and Gelanoglanis, comprising 31 species, are presently recognized as valid in the subfamily (Ferraris, 2007). Tatia comprises a group of relatively small (20-150 mm standard length), nocturnal auchenipterids [or centromochlins] that feed on small fruits and invertebrates (H. A. Britski, M. Goulding, pers. comm.). They are endemic to South America east of the Andes and are present in most of major drainages, including the Orinoco, Amazon, ParanáParaguay, and Uruguay, as well as northern coastal rivers from the Essequibo to Amapá State and Marajó Island, Brazil. Tatia is absent in the São Francisco river basin and small riverine basins along the Brazilian east coast. Tatia is the most speciose genus in the subfamily, with 12 species recognized here (Table 1). Tatia species occur in lentic sections of igarapés, rivers, and lakes, where they remain hidden in submerged trunks or rocky crevices during the day and emerge only at night to forage (Lowe-McConnell, 1964, 1975, 1987; Soares-Porto, 1995). At night, individuals of Tatia usually remain close to the surface near river banks or in the middle of the river, swimming in a very peculiar way (fast and erratic), and capturing fallen insects (F.C.T. Lima, pers. comm.). Some species occur in black water rivers, but none are restricted to these environments. Many members of the genus are beautifully colored and, consequently, very attractive to the ornamental fish trade. Tatia species, however, are not well suited for captivity because of their apparent intolerance for low oxygen conditions. Most do not survive transport to Europe and North America (Sands, 1984). The generic name Tatia was proposed by Miranda Ribeiro (1911: 360) for Charles Tate Regan of the British Museum of Natural History, London, in honor of his many contributions to the knowledge of the South American freshwater fishes. The group was erected to include two species previously ascribed to Centromochlus:Tatia intermedia (Steindachner) and T. aulopygia (Kner), based on the presence of a genital papilla over the anterior anal-fin rays (Miranda Ribeiro, 1911:353). After Miranda Ribeiro’s (1911) description the name Tatia was mentioned only in catalogues (e.g. Gosline, 1945) and practically forgotten. Subsequent authors such as Eigenmann & Allen (1942) and Fowler (1945a) described new species in the genus Centromochlus, without mentioning Tatia. Boeseman (1953) referred to Tatia, but described a new species as Centromochlus creutzbergi. Britski (1972) considered Tatia to be a junior synonym of Glanidium Lütken due to similarities of sexually dimorphic features. In his study of auchenipterids primarily from Suriname Mees (1974) redescribed Tatia and expanded the genus to 14 species, six of which he described as new: T. brunnea, T. concolor, T. galaxias, T. punctata, T. reticulata and T.simplex. Four additional species of Tatia have been described subsequently (Mees, 1988; Royero, 1992; Soares-Porto, 1995; Koch & Reis, 1996). Regarding interrelationships among auchenipterid genera, Ferraris (1988) and Curran (1989) presented independent phylogenetic hypotheses based on cladistic analysis. Ferraris (1988) recognized a monophyletic basal clade within auchenipterids “Centromochlidae” and removed some species previously assigned to Tatia to two undescribed genera, restricting the nominate genus to: T. aulopygia, T. intermedia, T. dunni, T. galaxias, and one undescribed species. Curran (1989) questioned the monophyly of the speciose genus Tatia. The author considered Tatia and Centromochlus as only distantly related; assigning Tatia as close to Auchenipterichthys. Soares-Porto (1998) stated Tatia sensu stricto as a monophyletic unit restricted to eight species: T. aulopygia, T. boemia, T. brunnea, T. creutzbergi, T. gyrina, T. intermedia, T. neivai, and T. strigata. Other species previously assigned to Tatia were transferred to Centromochlus, on the basis of derived characters (Soares-Porto, 1996, 1998). Most recently Ferraris (2007) listed twelve valid species of Tatia:T. aulopygia, T. boemia, T. brunnea, T. creutzbergi, T. dunni, T. galaxias, T. gyrina, T. intermedia, T. musaica, T. neivai, T. simplex, and T. strigata. The present paper gives a reappraisal of Tatia based on examination of numerous specimens in addition to those available to previous authors. Patterns of variation within and between species are considered throughout their distributions. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 497 Material and Methods Osteological features were examined in cleared and stained (CS) specimens prepared according to the procedures of Taylor & van Dyke (1985). Prior to clearing and staining, specimens were dissected when possible to determine gut contents, sexual maturity of gonads, and record myological information. Osteological data from some types or specimens poorly represented in ichthyological collections were obtained from radiographs (noted as “R” in the Material Examined section). Nomenclature of osteological elements follows The Zebrafish Information Network (ZFIN). Muscle names follow Sarmento-Soares & Porto (2006). Drawings were rendered from digital photographs prefereably of cleared and stained specimens. Straight-line measurements were made with a digital caliper, and recorded in tenths of a millimeter. Measurements included: standard length (SL, from snout tip to caudal-fin base); body depth (on nuchal shield, from origin of dorsal-fin spine to the belly); body width (widest distance between lateral surfaces of cleithra, taken between anterior-most margin of cleithral bone beneath pectoral-fin origin); caudal-peduncle depth (least distance between dorsal and ventral surfaces of caudal peduncle); caudal-peduncle length (from base of posterior-most anal-fin ray to point coinciding with origin of lower unbranched caudal-fin ray); predorsal length (from snout tip to origin of dorsal fin); preanal length (from snout tip to anal-fin origin); prepelvic length (from snout tip to pelvic-fin origin); dorsal-fin origin to pectoral-fin origin; dorsal-fin origin to pelvic-fin origin; pectoralfin origin to pelvic-fin origin; prepectoral length (from snout tip to pectoral-fin origin); dorsal-fin base (from origin of dorsal-fin spine to posterior-most base of dorsal-fin insertion); adipose-fin base (from origin of adipose fin fold to its posterior-most base); anal-fin base (distance between genital opening and posterior-most base of anal-fin insertion, measured under the same criteria for both males and females); dorsalfin spine length (from base of spine to its distal tip); pectoralfin spine length (from origin of spine to its distal tip, taken with the spine erected); postcleithral (humeral) process length (from anterodorsal margin of exposed process to posteriormost tip of process); first branched pelvic-fin ray (from base to tip of first branched pelvic-fin ray); longest anal-fin ray (from base to tip of first branched anal-fin ray); head length (HL, from snout tip to bony end of opercle); head width (between dorsalmost extents of opercular openings); snout depth (distance in median sagittal plane between posterior nostril and midventral contour of body); interorbital distance (least distance between dorsalmost margins of bony orbit); left internarial width (between left anterior and left posterior nostrils); anterior internarial distance (transverse distance between anterior nostrils); posterior internarial distance (transverse distance between posterior nostrils); snout length (from snout tip to anteriormost margin of eye); maxillary-barbel length (from base to tip, with barbel retracted); outer mentalbarbel length (from base to tip, with barbel retracted); inner mental-barbel length (from base to tip, with barbel retracted); orbital diameter (greatest horizontal dimension of eyeball); mouth width (between corners of closed mouth). Counts of fin rays and bony elements were obtained from alcohol-preserved and cleared and stained specimens. Vertebral counts included all rib-bearing centra but did not include any of the anterior, complex centrum elements without ribs, following Ferraris & Fernandez (1987), and included the compound caudal centrum (PU1+U1) as the last element. Hemal spine counts accompany the numbers for correspondent vertebra, as shown in Fig. 1. Count of branchiostegal rays were done only in cleared and stained specimens. The direction of dorsal and pectoral-fin spine serrations are referred to as antrorse for those pointing away from base of spine and retrorse for those bent towards base of spine. Male modified Nominal species Mees (1974) Ferraris (2007) Assignment herein Taxonomic status Centromochlus aulopygius Kner, 1857 Tatia aulopygia Tatia aulopygia Tatia aulopygia Valid Tatia boemia Koch & Reis, 1996 - Tatia boemia Tatia boemia Valid Tatia brunnea Mees, 1974 Tatia brunnea Tatia brunnea Tatia brunnea Valid Tatia caxiuanensis, new species - - Tatia caxiuanensis n.sp. Valid Centromochlus dunni Fowler, 1945 Tatia intermedia Tatia dunni Tatia dunni Valid Tatia galaxias Mees, 1974 Tatia galaxias Tatia galaxias Tatia galaxias Valid Centromochlus gyrinus Eigenmann & Allen, 1942 Tatia gyrina Tatia gyrina Tatia gyrina Valid Centromochlus intermedius Steindachner, 1877 Tatia intermedia Tatia intermedia Tatia intermedia Valid Tatia meesi, new species - -Tatia meesi n.sp. Valid Glanidium neivai Ihering, 1930 Tatia neivai Tatia neivai Tatia neivai Valid Tatia nigra, new species - -Tatia nigra n.sp. Valid Tatia strigata Soares-Porto, 1995 - Tatia strigata Tatia strigata Valid Centromochlus altae Fowler, 1945 Tatia altae Centromochlus altae Centromochlus altae Valid Tatia concolor Mees, 1974 Tatia concolor Centromochlus concolor Centromochlus concolor Valid Centromochlus creutzbergi Boeseman,1953 Tatia creutzbergi Tatia creutzbergi Junior synonym of Tatia gyrina Junior synonim Tatia musaica Royero, 1992 - Tatia musaica “Centromochlus” musaicus [incertae sedis in Centromochlinae] Valid, incertae sedis in Centromochlinae Centromochlus perugiae Steindachner, 1882 Tatia perugiae Centromochlus perugiae Centromochlus perugiae Valid Tatia punctata Mees, 1974 Tatia punctata Centromochlus punctatus Centromochlus punctatus Valid Tatia reticulate Mees, 1974 Tatia reticulata Centromochlus reticulatus Centromochlus reticulatus Valid Centromochlus schultzi Rössel, 1962 Tatia schultzi Centromochlus schultzi Centromochlus schultzi Valid Tatia simplex Mees, 1974 Tatia simplex Tatia simplex “Centromochlus” simplex [incertae sedis in Centromochlinae] Valid, incertae sedis in Centromochlinae Table 1. Taxonomic list of nominal species assigned to Tatia by previous authors and the status of those species as recognized in the present study. A systematic revision of Tatia 498 anal-fin segmented rays (lepidotrichia) may have adjacent segments with curved border, forming denticulations herein refered to as antrorse or retrorse. Institutional abbreviations follow Reis et al. (2003), with the exception of MBML for Museu de Biologia Professor Mello Leitão, Santa Teresa, Espírito Santo, Brazil and NUPELIA for Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura/ Fundação Universidade Estadual de Maringá, Maringá, Paraná, Brazil. Results Tatia Miranda Ribeiro Tatia Miranda Ribeiro, 1911: 360 [type species: Centromochlus intermedius Steindachner, 1877, by subsequent designation by Jordan, 1920: 545. Gender: feminine]. Diagnosis. Tatia is distinguished among the Centromochlinae by three uniquely derived features. The hyomandibula is elongate anterodorsally, not contacting the narrow metapterygoid and, instead, connected only to the trapezoidal quadrate (Fig. 2); anal-fin base of adult males is reduced (anal-fin base length 3.3-8.0% SL); and caudal peduncle is compressed and deep (caudal-peduncle depth 10.1-18.6% SL), with a middorsal keel posterior to adipose fin. A unique combination of restricted characters aids in distinguishing Tatia: first (anteriormost) nuchal plate present (Fig. 3, n1); infraorbital 1 bone short, limited to anterior corner of orbit; eye moderately large, between 17.4-42.9% HL; maxilla shorter than or same length as autopalatine; retractor tentaculi muscle absent, functionally substituted by maxillomandibular ligament (Sarmento-Soares & Porto, 2006); adult males with modified anal fin (all species), and first unbranched anal-fin ray non-segmented or with segments fused (except in T. brunnea). Generic description. Tatia comprises species with somewhat robust head; caudal peduncle much compressed laterally and deep; well-developed adipose eye lid; eye moderately large, and latero-dorsally located. Following characters used to distinguish species of Tatia (illustrations based on T. gyrina): Head: cranial fontanel always present (Fig. 3, fo); premaxilla transversely elongated, meeting its counterpart medially; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla very small, shorter than or same length as autopalatine; three nuchal plates present (Fig. 3, n1, n2, n3). Epioccipital process small, connected to third nuchal plate by ligaments (Fig. 3, pe). Mullerian ramus with distal tip shaped as slightly curved disc, its concave face superficially adjoined to anterior wall of gasbladder. Prevomer usually with well developed arrow-shaped lateral processes or with short lateral process. Prevomerian teeth present in T. galaxias and T. intermedia. Suspensorium (Fig. 2): Suspensorium bones in Tatia similar among all species and distinctive among Centromochlinae. Hyomandibula narrow, elongate, projected anteriorly as short membranous lamina (Fig. 2, hy). Anterior laminar projection of hyomandibula sutured only to quadrate, through cartilage ventrally and deeply dentate suture dorsally. Metapterygoid conical, dorsally sharp, with little laminar extension (Fig. 2, mt), joined to quadrate via cartilage block only (T. gyrina, T. caxiuanensis, T. meesi, T. strigata) or cartilage plus dentate suture (T. aulopygia, T. boemia, T. brunnea, T. dunni, T. galaxias, T. intermedia, T. neivai, T. nigra). Suspensorium deeply notched anterodorsally, thus metapterygoid not contacting hyomandibula. Quadrate trapezoidal, with broad base (Fig. 2, qu), connected to preopercle, hyomandibula and metapterygoid; long preopercle (Fig. 2, po) ventral margins sutured to both quadrate and hyomandibula; suprapreopercle present as short or robust canal bone (Fig. 2, sp); opercle laminate and broadly subtriangular (Fig. 2, op). Hyoid arch (Fig. 4): Urohyal narrow (Fig. 4, uh); short dorsal hypohyal (Fig. 4, dh) associated with comparatively large ventral hypohyal (Fig. 4, vh); anterior ceratohyal well developed (Fig. 4, ac), posterior ceratohyal smaller (Fig. 4, pc); branchiostegal ray articulated to hyoid arch; branchiostegal rays 5-7; 3-5 on anterior ceratohyal and two on posterior ceratohyal; posteriormost usually largest and flattened. No branchiostegal ray associated with interceratohyal cartilage between bones. Pharyngeal (gill) arches (Fig. 5): Basibranchial 1, in contact with urohyal (Fig. 5, ab), anterior to basibranchial 2; basibranchial 2 forming osseous rod, broadest anteriorly (Fig. 5, bb2) and usually separated by gap from basibranchial 3; basibranchial 3 shorter (Fig. 5, bb3), also broadest anteriorly; basibranchial 4 large, flattened and completely cartilaginous (Fig. 5, bb4); basibranchial 2 bordered laterally by cartilaginous head of hypobranchial 1; basibranchial 3 between cartilaginous head of hypobranchial 2 and cartilaginous hypobranchial 3; basibranchial 4 bordered laterally by cartilaginous head of ceratobranchial 4 and caudally by cartilaginous head of ceratobranchial 5. Hypobranchial 1 mostly osseous, elongate and expanded laterally, subtriangular, with cartilaginous ends; hypobranchial 2 mostly cartilaginous, subtriangular, with medial osseous part; hypobranchial 3 comFig. 1. Schematic representation of partial axial skeleton of Tatia boemia MCP 12949, 59.9 mm SL. Left side lateral view. Abbreviations:af, anal fin; dr, distal radials; hs15hs18, hemal spines 15 and 18; pf, pelvic fin; pr, proximal radials; r8r11, ribs 8 to 11; v8v18, vertebral centra 8 to 18. Scale bar = 1.0 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 499 pletely cartilaginous, more trapezoidal (Fig. 5, hb 1-3); hypobranchial 4 absent. Five ceratobranchials present, mostly ossified, with cartilage on both ends (Fig. 5, cb 1-5). First ceratobranchial supporting single row of rakers (not illustrated); fifth ceratobranchial expanded postero-medially to support lower pharyngeal toothplate with short conical teeth. Five epibranchials, all but fifth largely ossified except for cartilaginous ends; epibranchials 1 and 2 rod-like, without rakers; epibranchial 3 with posterior uncinate process; epibranchial 4 broad, with laminar extension; epibranchial 5 cartilaginous, reduced, located in axil between cartilaginous ends of epibranchial 4 and ceratobranchial 4. Pharyngobranchial 1 absent; pharyngobranchial 2 short, cartilaginous, somewhat rounded, placed between anteromedial cartilaginous tips of epibranchials 1 and 2; pharyngobranchial 3 elongate, ossified, with expanded posterior border; pharyngobranchial 4 ossified, supporting upper pharyngeal tooth plate with short conical teeth. Lateral line system: Infraorbital 1 short, with ventro-lateral process either clearly restricted to anterior border of eye or almost reaching ventral border of eye; infraorbitals thin and canalicular, forming incomplete or complete infraorbital series. Lateral line on body straight, inconspicuous, with ossified canal bones just anteriorly. Fins: Dorsal fin with major spine preceded by small dorsal locking spine and followed by 3-5 branched rays; pectoral fin with one spine plus 3-5 branched rays; pelvic fin with one unbranched plus 5 branched rays, margin rounded; adipose fin above anal-fin base; anal fin with 3 unbranched plus 6-8 branched rays; caudal fin with 8+9 principal rays, forked, lobes with rounded tips; dorsal caudal-fin lobe slightly elongate in males of some species. Ribs and vertebrae: Pleural ribs 7-11; first rib thicker than others; ribs becoming progressively smaller posteriorly. PostWeberian vertebrae 30-39. Sexual dimorphism. In catfishes of subfamily Centromochlinae the anal fin of sexually mature males is modified into a sperm conductor with the anal-fin rays and proximal radials directed posteriorly, aligned nearly parallel to vertebral axis (Ferraris, 1988; Soares-Porto, 1998). In mature males the anal fin is strongly modified such that it is supported by enlarged and joined proximal anal-fin radials (Ferraris, 1988; Soares-Porto, 1998) and by partially ossified distal radials. Anal-fin proximal radials are associated with the thickened and lengthened hemal spines of adjacent vertebrae. Modified male anal fin has three developed unbranched rays. The first unbranched ray is shortest, about one-quarter length of second unbranched ray, and with segments fused (except in T. brunnea). Some species have the first unbranched anal-fin ray preceded immediately by a tegumentary keel. The second and third unbranched rays are thick. In the Centromochlinae, Tatia is the only genus with species that bear segments that curve outwards, forming antrorse denticulations along the anterior margin of the third unbranched anal fin ray in adult males. Remarks. Two of the nominal species assigned to Tatia by Ferraris (2007) are not herein recognized as members of this genus. Both Tatia musaica Royero and Tatia simplex Mees lack the derived characters listed above for Tatia: thin, anterodorsally elongate hyomandibula (vs. broad in both C. musaicus and C. simplex); caudal peduncle laterally compressed (vs. ellipsoid); proportionally deeper caudal peduncle, depth 10.1-18.6% SL (vs. 7.9-9.6% SL in C. musaicus and 9.210.0% SL in C. simplex); first nuchal plate present (vs. abFig. 2. Right suspensorium of Tatia gyrina, INPA 20971, 28.0 mm SL. Lateral view. Abbreviations: aa, angulo-articular; dn, dentary; hy, hyomandibula; io, interopercle; mt, metapterygoid; op, opercle; po, preopercle; qu, quadrate; sb, subpreopercle; sp, suprapreopercle. Scale bar = 1.0 mm. Fig. 3. Neurocranium of Tatia gyrina, INPA 20971, 28.0 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleitrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1.0 mm. A systematic revision of Tatia 500 sent); maxilla shorter than or same length as autopalatine (vs. longer than autopalatine). These two species are incertae sedis in Centromochlinae (see Table 1), based in part on interrelationships analysis by Soares-Porto (1996), and are herein provisionally allocated under Centromochlus. The monophyly and interrelationships among species of Tatia were hypothesized by Soares-Porto (1998), who considered the clade T. gyrina plus T. creutzbergi as sister to all other Tatia species. Inseminating reproductive mode (sensu Burns et al., 1997) has been documented within the Auchenipteridae (von Ihering, 1937; Loir et al., 1989; Meisner et al., 2000). In the centromochlin catfishes, inseminating is supposed to take place (Loir et al., 1989; Franke, 1990), but a reproductive behavior is not yet reported. During reproductive phase, the anal-fin rays change their position probably channeling for discharge of seminal ducts, acting as a sperm conductor during reproduction. Such a morphological change was observed in some males of Centromochlus romani and also in T. nigra. The sperm probably runs along the spoon shaped anal-fin rays, and the fish may press the fin against the belly of the female, for inseminating. Morphological evidences suggesting inseminating reproductive mode in Tatia are the intumescent female genital papilla (as in T. gyrina and T. nigra) and the spoon-shaped laterally curved male anal fin (observed in T. nigra). A detailed analysis of morphological changes of the reproductive tract needs to be accomplished by histological preparations, and is out of the scope of present contribution. Distribution. Species of Tatia are broadly distributed in the regions east of the Andean Cordilleras (Fig. 6). Tatia ranges from the Guarapiche river, Orinoco basin, in Venezuela, to the Pelotas river, Uruguay drainage, in Brazil. The group is found in major continental river basins, such as the Amazon, Orinoco and Paraná-Paraguay; as well as in the Essequibo and small coastal drainages in French Guiana, Suriname and Amapá and Marajó island in northern Brazil. Although well distributed in cis-Andean South America, the group is not known from certain drainage basins, including the São Francisco and small coastal river drainages of northeastern and far eastern Brazil. Tatia is found, however, in headwaters of Paraíba do Sul basin, São Paulo State. The absence of Tatia from certain areas may be a function of inadequate collections from those river basins or may reflect actual disjunct distributions of the group as whole. Species Account Tatia aulopygia (Kner, 1857) Figs. 7-9 Centromochlus aulopygius Kner, 1857: 432, Pl. 8 (fig. 26) [type locality: Guaporé river]. -Steindachner, 1876: 664-665 [no locality]. Eigenmann & Eigenmann, 1890: 270 [citation]. Pearson, 1937: 110 [Mamoré river drainage]. Tatia aulopygia. Miranda Ribeiro, 1911: 361 [generic designation]. Gosline, 1945: 10 [listing]. Mees, 1974: 59-63 [notes and distribution, in part, Maciel, Guaporé river]. Sands, 1984: 38-39 [listing]. Lauzanne & Loubens, 1985: 112 [Mamoré river drainage]. Burgess, 1989:242 [listing]. Soares-Porto, 1995:204 [citation]. Soares-Porto, 1998: 331350 [citation]. Lasso et al., 2001:97 [citation]. Ferraris, 2003:476 [checklist]. Ferraris, 2007: 77 [checklist]. Centromochlus intermedius. Fisher, 1917: 422 [in part, Maciel, Guaporé river]. Pearson, 1937: 110 [Mamoré river drainage]. Diagnosis. Tatia aulopygia is distinguished from all other species of Tatia by having a short cranial fontanel, with the opening restricted to the frontals (Fig. 8); a genital papilla Fig. 4. Right hyoid arch of Tatia gyrina, INPA 20971, 28.0 mm SL. Medial view. Abbreviations: ac, anterior ceratohyal; br, branchiostegal rays; dh, dorsal hypohyal; ic, interceratohyal cartilage; ih, interhyal; pc, posterior ceratohyal; vh, ventral hypohyal; uh, urohyal. Scale bar = 1.0 mm. Fig. 5. Pharyngeal arches of Tatia gyrina, INPA 20971, 28.0 mm SL. Dorsal view. Abbreviations: ab, anterior (first) basibranchial; bb2, basibranchial 2; bb3, basibranchial 3; bb4, basibranchial 4; cb1-5, ceratobranchials 1 to 5 (anterior to posterior); eb1-4, epibranchials 1 to 4 (anterior to posterior); hb1-3, hypobranchials 1 to 3; pb3, pharingobranchial 3; pb4, pharingobranchial 4. Scale bar = 1.0 mm.. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 501 with thick flap of skin around the deferent duct in males (Fig. 9); and a notched anal fin in adult males (Fig. 9). The species also is distinguished from congeners by a combination of characteristics: nasal bone partially sutured to lateral margin of mesethmoid; anal fin with 7-8 branched rays; 10-11 ribs; 38-39 post-Weberian vertebrae. Additional features useful for distinguishing this species include: third nuchal plate well projected laterally with curved tip; and caudal-fin lobes of mature females similar in length, but mature males with slightly elongated upper lobe. Description. Measured adult specimens 75.2-159.0 mm SL; morphometric data presented in Table 2. Body deep, head slightly depressed dorsoventrally. Head large, robust, outline of head in dorsal view somewhat elliptical, broader than long. Dorsal outline of trunk from dorsal-fin base to caudal peduncle increasingly compressed posteriorly. Lateral profile of head from snout tip to above opercular margin slightly convex to pectoral-fin insertion. Ventral profile of head and abdomen flat. Ventral profile of body gently curved, concave behind anal-fin origin. Head integument thin, cranial roof visible; adipose eye lid well-developed; eye dorsolaterally located in anterior portion of head; mouth terminal, upper lip extended posterolaterally as well-developed fleshy rictal fold; anterior nostril tubular, located on anterior border of snout, above lip; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils slightly shorter than distance between posterior ones. Maxillary barbel short, extending slightly beyond tip of postcleithral process, sometimes shorter; mental barbels short, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 65.0-75.0% length of outer mental. Postcleithral process almost reaching vertical through origin of dorsal fin. Caudal peduncle deep, depth about 14.015.8% SL. Rostral border of cranium broad with large mesethmoid; Fig. 6. Drainage map of northern South America illustrating the geographic distribution of the species of Tatia. Symbols may represent more than one locality. Base map by Marilyn Weitzman. A systematic revision of Tatia 502 premaxilla underneath with synchondral articulation; cranial fontanel short, ovoid, bounded by frontal (Fig. 8); nasal ossified with wide medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla very small, shorter than autopalatine; prevomer expanded anteriorly with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with four to five rows of conical teeth. First nuchal plate somewhat pentagonal; second nuchal plate deeply concave along lateral margin; third nuchal plate curved, projected laterally. Epioccipital process small. Suspensorium, hyoid arch and opercular bones as in generic description. Suprapreopercle present as short robust canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal. Basibranchials 2 and 3 fused together forming osseous rod with broad cartilaginous anterior tip; basibranchial 4 large flattened and completely cartilaginous; fused basibranchial 2 plus 3 bordered laterally by cartilaginous head of hypobranchial 1, cartilaginous head of hypobranchial 2 and cartilaginous hypobranchial 3. Basibranchial 4 bordered laterally by cartilaginous head of ceratobranchial 4 and posteriorly by cartilaginous head of ceratobranchial 5. Hypobranchials, ceratobranchials, epibranchials and pharyngobranchials as described in generic description. Four infraorbital bones in incomplete series. Infraorbital 1 broad with short ventro-lateral process on anterior border of eye; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and two posterior canal bones, one long and one short, forming posterior orbital rim. Lateral line on body with ossified canal bones posteriorly to vertical through pelvic-fin origin. Dorsal fin I,5 (n=7); dorsal-fin spine with 14-16 antrorse serrations along entire anterior margin; posterior margin smooth. Pectoral fin I,5 (n=7); pectoral-fin spine with 21-24 antrorse serrations along anterior margin; small serrations close to spine base; 14-16 retrorse serrations along posterior margin; serrations along both margins progressively larger toward spine tip. Pelvic fin i,5 (n=7); margin rounded. Adipose fin small, origin on vertical through end of anal-fin base. Anal fin iii,7-8 (n=7); anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 1820 upper procurrent, 17-20 lower procurrent rays (n=7). Pleural ribs 10-11 attached to consecutive vertebrae. PostWeberian vertebrae 38-39 (n=4). Fig. 7. Tatia aulopygia,(a) INPA 11080, male, 104.6 mm SL, Guaporé river, Amazonas State, Brazil. (b) ZMA 114.280, young female, 46.3 mm SL, Humaitá, Amazonas State, Brazil. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 503 Color in alcohol. Head and body mottled with dark and light brown patches of pigmentation, sometimes forming faint blotches irregularly distributed over sides of body (Fig. 7). Lips and chin dark brown. Dorsal fin dark brown, pectoral fin usually pale brown or not pigmented. Adipose fin pale brown, caudal fin usually with transverse bars but young specimens with whitish spots. Pelvic fins and belly whitish. Color variation. Body coloration in T. aulopygia is somewhat variable, usually with large bands or blotches irregularly distributed over sides of body. In some specimens coloration is uniformly dark or pale brown, with caudal fin mottled. Some young specimens have small spots over ventrolateral parts of body and a barred caudal fin. Mees (1974) noted the presence of longitudinal pale streaks on the body and observed irregular patches of pigmentation on specimens from the Guaporé river, but all specimens available to him are now very faded and unsuitable for accurate description of coloration. Recent expeditions to the Guaporé river provided more adult specimens of T. aulopygia, on which the above description is based. Sexual dimorphism. Based on examination of gonads, T. aulopygia attains sexual maturity above 80 mm SL. In mature females a genital papilla is not evident. The genital papilla of mature males is visible, with a thick skin flap around the deferent duct. The anal fin of mature males (Fig. 9) is strongly modified, with the three unbranched and first two branched rays enlarged and thickened. The first unbranched anal-fin ray is immediately preceded by a tegumentary keel. The second unbranched ray is intermediate in size between the neighboring first and third rays. The third unbranched ray is the longest, forming a minute pointed fin tip (Fig 9, uiii); distal segments are smaller, and antrorsely curved (Fig. 9, ac). The first branched ray is slightly curved towards the fin tip, bearing retrorsely curved distal segments (Fig. 9, rc). The fourth and fifth branched rays are shorter, forming a central notch in distal margin of the anal fin. The posterior branched rays are normally developed and not reduced. The hemal spines interdigitating with anal-fin pterygiophores are thick in males; but those hemal spines are undifferentiated in females. Caudal-fin lobes are of comparable length in mature females, whereas upper lobe is more elongated in mature males. Specimens of T. aulopygia historically housed in collections are mostly juveniles, with only one syntype bearing a modified anal fin. Information on male anal-fin morphology was improved by recent captures of adult specimens in the Amazon basin. Table 2. Morphometric data for Tatia aulopygia. SD = standard deviation. Range Mean SD N Standard length 75.2-159.0 92.4 7 Percents of standard length Body depth 15.2-20.3 17.8 1.69 7 Body width 18.7-23.5 20.4 1.96 7 Caudal peduncle depth 14.0-15.8 14.6 0.82 7 Caudal peduncle length 23.4-28.4 25.9 1.98 7 Predorsal length 29.3-33.3 31.7 1.37 7 Preanal length 64.4-70.6 67.5 1.99 7 Prepelvic length 46.7-51.8 49.4 1.69 7 Dorsal origin to pectoral origin 19.1-24.2 21.8 1.89 7 Dorsal origin to pelvic origin 26.0-29.5 27.2 1.25 7 Pectoral origin to pelvic origin 30.5-35.5 32.3 1.85 7 Prepectoral length 17.8-22.5 20.0 1.60 7 Dorsal-fin base length 6.8-11.8 9.5 1.91 7 Adipose-fin base length 7.9-12.7 10.1 1.92 7 Anal-fin base length 3.3-10.8 7.4 3.39 7 Dorsal-fin spine length 16.0-21.2 18.6 1.92 7 Pectoral-fin spine length 19.5-24.0 22.1 1.91 7 Postcleithral process lenght 15.8-19.4 16.5 1.86 7 First branched pelvic-fin ray 10.7-15.3 13.2 1.67 7 Longest anal fin ray 5.2-12.5 8.0 2.58 7 Maxillary barbel length 22.0-27.3 24.7 1.90 7 Outer mental barbel length 7.3-13.3 9.0 1.88 7 Mental barbel length 4.1-10.0 5.6 1.92 7 Head length 21.8-26.6 23.4 1.80 7 Percents of head length Head width 75.2-80.2 78.1 1.84 7 Snout depth 41.5-45.9 44.0 1.79 7 Interorbital distance 53.2-58.9 57.7 1.94 7 Left internarial width 21.1-25.0 22.9 1.36 7 Anterior internarial distance 38.4-43.8 40.8 1.81 7 Posterior internarial distance 34.5-39.5 37.8 1.69 7 Snout length 36.6-41.2 38.5 1.89 7 Orbital diameter 23.1-26.5 24.6 1.51 7 Mouth width 50.4-55.5 53.1 1.94 7 Fig. 8. Neurocranium of Tatia aulopygia, INPA 11080, 80.0 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1.0 mm. A systematic revision of Tatia 510 usually with 3-5 separated dermal segments (lepidotrichia). A segmented first unbranched ray was observed in most Suriname specimens, but not in all, and may be associated to regional differentiation. The first unbranched anal-fin ray is immediately preceded by a tegumentary keel (Fig. 15, tk). The second unbranched ray has an intermediate size between the neighboring first and third rays. Third unbranched is the longest ray forming a long sharp pointed fin tip together with the first branched (Fig. 15, uiii). Third unbranched distal segments are antrorsely curved (Fig. 15, ac). First branched ray bearing retrorsely curved distal segments (Fig. 15, rc). Posterior branched rays are normally developed and progressively shorter; with last ray reduced (Fig. 15, b7). Hemal spines 16-19 interdigitate with the anal-fin pterygiophores; hemal spines 15-17 or 16-18 are thickened in mature males, but undifferentiated in females. The caudal-fin lobes have the same length in mature females, whereas upper lobe is elongated in mature males. Distribution. Tatia brunnea was described from the Suriname and Marowijne-Maroni river basins in Suriname. It was recorded in French Guiana from the Maroni and Sinnamary river basins. In Brazil it occurs in the Negro river drainage and at a single locality in Central Amazon basin, in the Trombetas river drainage (Fig. 6). Remarks. Until recently, T. brunnea was thought to be restricted to Suriname (Ferraris, 2003), although it was previously recorded in the Negro river as well (Wallace, 2002). The overall coloration of T. brunnea ressembles that of T. dunni, from upper Amazon. Details in coloration of caudal fin helps to distinguish between these two species, as in T. brunnea the caudal fin is whitish with dark spots or bands (vs. darker with whitish blotches in T. dunni). Additional distinctions include a wide head in T. brunnea, 86.6-93.4% HL (vs. narrow inT. dunni, 76.0-80.1% HL); a wide mouth, 54.0-59.7% HL (vs. narrow, 48.1-52.3% HL); and a male modified anal fin with sharply pointed distal tip (vs. short rounded distal tip). Tatia brunnea occurs in sympatry with T. intermedia in some rivers in Suriname and French Guiana and also in the Trombetas river. Material examined. 128 specimens (16.2-97.4 mm SL). Holotype. Suriname: RMNH 26196, 56.5 mm SL, Compagnie stream (holotype of Tatia brunnea). Paratypes. Suriname: AMNH 58390, 1 (54.6 mm SL) (R), Kamaloe stream, right margin of Marowijne river. RMNH 26197, 3 (47.6-60.0 mm SL), Compagnie stream; RMNH 26198, 3, 1 CS (35.1-40.3 mm SL), Kwambaolo stream, near dam; ZMA 105.526, 4 (26.5-36.6 mm SL), Gran river, 63 Km south of Affobakka; ZMA 105.860, 1 (41.5 mm SL) (R), Sara stream, about 27 Km south of dam; ZMA 105.849, 7 (27.0-52.2 mm SL) (R), Maka stream, tributary of Lawa river, Marowijne district (paratypes of Tatia brunnea). Non-type specimens: Brazil: Amazonas: ANSP 165747, 2, igarapé Castanho, Negro river; CAS 76790, 2 (70.3-80.2 mm SL), Cuieras river; INPA 14228, 2 (96.997.4 mm SL), Urubu river, igarapé of Gavião, Farm Esteio, Negro river basin; INPA 15989, 1 (66.6 mm SL), Presidente Figueiredo, Urubu river, Negro river basin; INPA 16577, 1 (89.0 mm SL), Jauaperi river, igarapé Cambina, Negro river basin; MCZ 52670, 2 (28.2-37.0 mm SL), Cuieras river in isolated pool; MZUSP 9352, 1 (18.6 mm SL), Central lake, left margin of Negro river between Camanaú and Apeú rivers; MZUSP 31075, 1 (34.0 mm SL), Negro river, Barcelos, island lake; MZUSP 44126, 1 (38.3 mm SL); MZUSP 44258, 2 (23.4-36.7 mm SL), Negro river, Anavilhanas archipaelago; ZMA 119.949, 1 (58.0 mm SL), Negro river and tributaries; MZUSP 81139, 1 (78.0 mm SL), Tiquié river, between communities of Caruru and Boca de Sal, Negro river drainage; MZUSP 81177, 2 (36.9-59.4 mm SL), Tiquié river, mouth of igarapé Açaí, near São Pedro community, Negro river drainage; MZUSP 81250, 10, 1 CS (44.6-81.7 mm SL), Tiquié river, between communities of São Pedro and Caruru upstream from waterfalls, Negro river drainage; ZMA 119.949, 1 (58.0 mm SL), Negro river and tributaries. Pará: MNRJ 15332, 1 (32.7 mm SL), MNRJ 15333, 1 (44.4 mm SL) and MNRJ 15334, 3, 1 CS (31.1-43.4 mm SL), igarapé Saracazinho, tributary of Batata lake, Porto Trombetas. French Guiana: RMNH 28570, 3 (29.6-50.0 mm SL), Awahakiki river; RMNH 28569, 2 (34.3-41.4 mm SL) and RMNH 28571, 4, 1 CS (25-37 mm SL), Balaté stream; RMNH 30494, 1 (70.0 mm SL), Petit-Saut, Sinnamary. Suriname: AMNH 58391, 2 (65.3-75.4 mm SL), Suriname river near Botopasi; RMNH 27530, 3 (26.7-28.0 mm SL), upper Loë river, tributary of Litani river; RMNH 28568, 2 (42.5-45.0 mm SL), stream below Acarouany; RMNH 28654, 1 (51.5 mm SL), stream below Bivouac downstream from Lombok waterfalls; RMNH 28655, 1 (54.0 mm SL), tributary at right margin of Nickerie river below Blanche Marie Falls; RMNH 28656, 2 (50.081.0 mm SL), tributary at right margin of Kaboeri stream, Corantjn river basin; RMNH 28658, 2 (45.1-74.0 mm SL), tributary at right margin of Kabalebo river, about 8 Km below Avanavero waterfalls; USNM 226124, 1, stream south of Matapi, Nickerie district; USNM 226125, 5 (16.2-23.3 mm SL), tributary of Corantijn river, north of Tiger Falls, Nickerie district; ZMA 105.831, 3 (34.4-60.2 mm SL), tributary of Nickerie river south of Stondansie Vallen. Tatia caxiuanensis, new species Figs. 16-18 Holotype.MPEG 9859, male (32.6 mm SL), Brazil, Pará: município de Melgaço, Estação Científica Ferreira Pena, Curuá river, Caxiuanã, 01o44’53”S 51o27’13”W, 1 Nov 1999, R. Barthem and team. Fig. 15. Male modified anal fin of Tatia brunnea, RMNH 26196, holotype, 56.5 mm SL. Left side lateral view. Abbreviations: ac, antrorsely curved denticulation; b1, branched first ray; b7, branched seventh ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar =1.0 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 511 Paratypes. Brazil, Pará: MPEG 6201 (7, 1 CS, 29.3-40.7 mm SL); MNRJ 28821 (2, 31.3-35.3 mm SL), all collected with the holotype. Diagnosis. Tatia caxiuanensis is distinguished from its congeners by a distinctive male modified anal fin, with elongate rays, with no denticulations on ray segments. The new species is also distinguished by the following combination of characters, as cranial fontanel wide, with a single opening; infraorbital 1 with pronounced ventral process, almost reaching the antero-ventral border of eye rim; nasal ossified as tubes, with no medial flanges of bone and not sutured to mesethmoid; five branched pectoral-fin rays; and snout deep, depth more than 46.7% HL. Additional features useful for distinguishing T. caxiuanensis include caudal fin lobes with about the same length in both adult females and males; postWeberian vertebrae 32; and a smaller adult size, less than 50.0 mm SL. Description. Measured specimens 29.3-40.7 mm SL; morphometric data presented in Table 5. Body slim, head slightly depressed dorso-ventrally. Head robust, outline of head in dorsal view almost rectangular, broader than long. Dorsal outline of trunk from dorsal-fin base to caudal peduncle gradually compressed laterally. Lateral profile of head from snout tip to above opercular margin slightly convex until pectoralfin insertion. Ventral profile of head and abdomen flat. Ventral profile of body gently curved behind anal fin. Head integument thick, cranial roof difficult to visualize; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended postero-laterally as well-developed fleshy rictal fold; snout margin rounded; anterior nostril tubular, located on anterior border of snout, above lip; posterior nostril thin, rounded, limited by small skin flap; transverse distance between anterior nostrils proportionally the same as distance between posterior ones. Maxillary barbel of moderate size, extending beyond posterior tip of postcleithral process, reaching vertical through origin or middle of dorsal fin; four mental barbels, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 70.0-78.0% length of outer mentals. Postcleithral process well developed, almost reaching vertical through origin of dorsal fin. Caudal peduncle moderately deep, its depth about 11.0-13.0% SL. Rostral border of cranium broad with mesethmoid broader than longer, premaxilla underneath with synchondral articulation; cranial fontanel elliptical, with single large opening, bounded by mesethmoid and frontal; nasal ossified, tubular, with no medial flanges (Fig. 17). Autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla about same size of autopalatine; prevomer expanded with a well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with three rows of conical teeth. First nuchal plate short, pentagonal; second nuchal plate laterally concave; third nuchal plate projected laterally, with pronounced narrow tip. Epioccipital process small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description.Suprapreopercle present as long canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal. Basibranchial 2 forming osseous rod with broad cartilaginous anterior tip, separated from shorter basibranchial 3. Four infraorbital bones in incomplete series. Infraorbital 1 thin, with short ventro-lateral process around anterior border of eye; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and by two posterior canal bones much close to sphenotic, forming rear of orbit. Lateral line on body with ossified canal bones only near head. Dorsal fin I,5; dorsal-fin spine with 15-17 antrorse serrations along entire anterior margin, posterior margin smooth. Pectoral fin I,5; pectoral-fin spine with 17-20 antrorse serrations along anterior margin; 14-15 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5, margin rounded. Adipose fin large, origin on vertical through middle anal-fin base. Holotype Range Mean SD N MPEG 9859 (n=10) Standard length 32.6 29.3-40.7 32.8 10 Percents of standard length Body depth 17.8 14.7-19.9 17.1 1.46 10 Body width 21.5 19.8-22.2 20.9 0.68 10 Caudal peduncle depth 13.0 11.0-13.0 11.9 0.71 10 Caudal peduncle length 25.5 25.5-30.0 27.7 1.97 10 Predorsal length 30.7 28.5-33.8 31.0 1.52 10 Preanal length 72.4 62.1-72.4 65.9 3.68 10 Prepelvic length 46.9 46.4-51.1 48.3 1.36 10 Dorsal origin to pectoral origin 23.0 19.0-23.4 21.5 1.42 10 Dorsal origin to pelvic origin 29.1 25.2-29.9 28.0 1.57 10 Pectoral origin to pelvic origin 30.4 30.0-35.6 33.0 1.92 10 Prepectoral length 19.3 17.2-22.7 19.9 1.54 10 Dorsal-fin base length 10.1 8.6-11.4 10.1 0.89 10 Adipose-fin base length 11.7 9.3-14.0 12.2 1.54 10 Anal-fin base length 4.3 4.2-11.9 8.2 2.79 10 Dorsal-fin spine length 19.9 14.5-19.9 18.0 1.65 10 Pectoral-fin spine length 20.2 16.9-22.9 21.1 1.69 10 Postcleithral process length 17.2 16.0-22.4 18.0 1.83 10 First branched pelvic-fin ray 13.2 12.0-15.9 13.4 1.15 10 Longest anal fin ray 10.7 7.4-12.3 10.5 1.38 10 Maxillary barbel length 34.4 30.0-35.5 33.4 1.97 10 Outer mental barbel length 8.9 7.3-10.6 8.9 0.86 10 Mental barbel length 6.4 4.7-7.6 6.3 0.78 10 Head length 24.2 19.9-27.0 23.7 1.98 10 Percents of head length Head width 77.2 74.0-79.2 76.8 1.89 10 Snout depth 48.1 46.8-50.7 48.7 1.75 10 Interorbital distance 57.0 54.4-59.2 56.8 1.89 10 Left internarial width 24.1 21.5-27.6 23.4 1.74 10 Anterior internarial distance 40.5 38.9-44.1 41.5 1.51 10 Posterior internarial distance 41.8 38.3-43.4 40.4 1.52 10 Snout length 39.2 34.7-39.5 37.2 1.95 10 Orbital diameter 29.1 26.5-31.6 28.5 1.74 10 Mouth width 50.6 46.5-52.0 49.3 1.91 10 Table 5. Morphometric data for Tatia caxiuanensis. SD = standard deviation. A systematic revision of Tatia 512 Anal fin iii, 7; anal-fin pterygiophores in 8 rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 5-8 upper procurrent, 5-6 lower procurrent rays. Caudal fin lobes about same length in both adult females and males. Nine pleural ribs attached to consecutive vertebrae. Post-Weberian vertebrae 32 (n=1). Color in alcohol. Dorsal mid-line and latero-dorsal parts of body dark brown, with many small dark chromatophores, less concentrated over lips and chin. Head and nuchal shield dark. Ventrolateral parts of body pale, belly whitish. Dorsal-fin spine dark pigmented, subsequent rays grayish with dark base. Pectoral, pelvic, anal and adipose fins hyaline. Caudal fin dark brown, with dark chromatophores on fin rays. Sexual dimorphism. Based on observation of gonads, all examined T. caxiuanensis are adults. In females a genital papilla is not evident. The genital papilla of mature males is visible, with a skin tube around deferent duct. The anal fin of mature male is strongly modified with the second and third unbranched plus first branched rays elongated and thickened, ending in a rounded curved tip (Fig. 18, uiii, b1). No tegumentary keel precedes the first unbranched anal-fin ray. The second unbranched ray is elongated, with an intermediate size between the neighboring first and third rays. The third unbranched and first branched rays are the longest (Fig. 18, uiii, b1). The distal most segments of the third unbranched ray are antrorsely curved (Fig. 18, ac). The second branched ray has a narrow tip. Posterior branched rays are progressively shorter and not reduced. Distribution. Known only from the type locality in Curuá river, lower Amazon basin, about 330 km southwest from the city of Belém, Pará, Brazil (Fig. 6). Etymology. The specific name, caxiuanensis, is in reference to the Floresta Nacional de Caxiuanã, a preservation area where the catfishes were caught. Remarks. Tatia caxiuanensis is one of the smallest Tatia, reaching maturity at 29.3 mm SL. Only T. gyrina reaches maturity at a smaller size (28 mm SL). Fig. 16. Tatia caxiuanensis.(a) holotype, MPEG 9859, male, 32.6 mm SL. (b) paratype, MPEG 6201, female, 40.7 mm SL, Caxiuanã, Pará State, Brazil. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 513 Tatia dunni (Fowler, 1945) Figs. 19-21 Centromochlus intermedius. Steindachner, 1882: 4 [Jutaí and Jatuarana]. Eigenmann & Eigenmann, 1888: 156 [Tajapuru, Tefé, Jatuarana, Icá, Jutaí, Lago Aleixo]. Eigenmann & Eigenmann, 1890: 269 [Amazonas, Solimões and tributaries]. Centromochlus aulopygius. Eigenmann & Eigenmann, 1891: 34 [in part, Amazonas, Solimões and tributaries]. Miranda Ribeiro, 1968:10, fig. IX [Amazonas]. Tatia intermedia. Miranda Ribeiro, 1911: 360 [in part, Jutaí, Jutuarana, Tajapuru, Teffé, Içá, Lago Aleixo]. Gosline, 1945: 10 [Amazonas, Solimões and Tributaries]. Sands, 1984: 37 [reference]. Ortega & Vari, 1986:14 [reference]. Burgess, 1989: 242, pl. 113 [Amazon]. Soares-Porto, 1998: 333 [citation]. Centromochlus dunni Fowler, 1945b: 111, figs. 11-13 [type locality: Colombia, Morelia, Caquetá river drainage]. Fowler, 1951: 462 [upper Amazon, Colombia]. Rössel, 1962: 20 [no locality]. Lüling, 1963: 50, fig. 15 [Quisto Cocha, Iquitos]. Böhlke, 1984:24 [reference]. Tatia aulopygia. Miranda Ribeiro, 1962: 10 [Amazonas]. Tatia dunni. Ferraris, 2003:476 [checklist]. Ferraris, 2007: 77 [checklist]. Diagnosis. Tatia dunni is distinguished by a unique combination of characteristics: nasal ossified with narrow medial flanges partially sutured to lateral margin of mesethmoid; analfin rays iii, 6-7; modified anal fin in mature males with short tip; first unbranched anal-fin ray with segments fused; last branched ray normally developed, not reduced (Fig. 21); ribs 10; and vertebrae 35. Additional features useful for distinguishing T. dunni include details in coloration, as: contour of mouth dark, same color as head; posterior border of nuchal shield usually dark; pectoral-fin spine usually dark brown; body coloration with irregular blotches or stripes, large specimens with faint stripes or blotches; and caudal fin dark with whitish blotches. Description. Measured adult specimens 66.1-114.5 mm SL; morphometric data presented in Table 6. Body deep, head depressed dorso-ventrally. Head robust, outline of head in dorsal view somewhat elliptic, slightly broader than long. Trunk from dorsal-fin base to caudal peduncle becoming gradually compressed laterally. Outline of head in dorsal view from snout tip to opercular margin slightly convex until pectoral-fin insertion. Ventral profile of head and abdomen slightly convex. Ventral profile of body compressed behind anal-fin origin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended posterolaterally as well-developed fleshy rictal fold; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils proportionally the same as distance between posterior ones in HL. Maxillary barbel short, extending close to posterior margin of postcleithral process; mental barbel short, tips not reaching pectoral-fin base; inner mental barbel about 60.0-90.0% length of outer mentals. Postcleithral process almost reaching vertical through middle or end of dorsal fin. Caudal peduncle deep, depth about 14.1-18.6% SL. Rostral border of cranium broad with mesethmoid broader than long; premaxilla underneath with synchondral articulation; cranial fontanel elliptical, bounded by mesethmoid and frontal (Fig. 20); nasal ossified with narrow medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxFig. 17. Neurocranium of Tatia caxiuanensis, new species, MPEG 6201, 29.3 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. Fig. 18. Male modified anal fin of Tatia caxiuanensis, new species, MPEG 6201, 29.3 mm SL. Left side lateral view. Abbreviations: as, antrorsely curved segment; b1, branched first ray; b7, branched seventh ray; dd, deferent duct; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar =1.0 mm. A systematic revision of Tatia 514 illa about same size of autopalatine; prevomer expanded anteriorly with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with three to four rows of conical teeth. First nuchal plate trapezoid; second nuchal plate slightly concave along lateral margins; third nuchal plate curved, projected laterally, with broad tip. Epioccipital process very small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as short canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last two flattened and expanded. Five infraorbital bones in incomplete series. Infraorbital 1 flattened with short ventro-lateral process; remaining infraorbitals thin, reduced to canalicular portions. Infraorbitals 2 and 3 close to infraorbital 1, followed by non-ossified portion of canal below eye and by two posterior short canal bones, forming posterior orbital rim. Lateral line on body with ossified canal bones posteriorly to vertical through pelvic fin origin. Dorsal fin I,4-5, rarely I,4 (n=13); dorsal-fin spine with 1315 antrorse serrations along entire anterior margin; posterior margin smooth. Pectoral fin I,5 (n=13); pectoral-fin spine with 17-19 antrorse serrations along anterior margin; 11-13 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5 (n=13), margin rounded. Adipose fin small, origin on vertical through end of anal-fin base. Anal fin iii, 6-7 (n=13); anal-fin pterygiophores in 8 rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 11-18 upper procurrent, 11-20 lower procurrent rays (n=13). Pleural ribs 10, attached to consecutive vertebrae. Post-Weberian vertebrae 35 (n=5). Color in alcohol. Coloration in preserved specimens umber, with rather long longitudinal pale grayish to whitish irregular blotches; dark markings form reticulations; under surface of head and abdomen whitish; fins with darker markings, more contrasted on caudal (Fowler, 1945b: 111). Dorsal surface of head almost dark brown; posterior part of nuchal shield faint, usually light brown. Contour of lips and anterior nostrils usually dark. Ventral part of head dark brown around chin barbels. Caudal fin dark with whitish spots over lobes. Color variation. Tatia dunni usually has faint irregular bands Fig. 19. Tatia dunni.(a) ANSP 71705, holotype, male, 83.3 mm SL, Caquetá river drainage, Colombia. (b) FMNH 88187, female, 77.5 mm SL, Conambo river, Ecuador. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 515 and spots over body. Some T. dunni, from the Peruvian Amazon, have a dark brown body and mottled anal fin (INHS 43890). Large specimens from the Purus river, in central Amazonia, usually have a completely dark body (INPA 17182) or a lightly spotted coloration (INPA 17184). Sexual dimorphism. Based on examination of gonads, T. dunni attains sexual maturity above 70 mm SL. In mature females a genital papilla is not evident. The genital papilla of mature male is visible, with an emergent deferent duct. The anal fin of mature male (Fig. 21) is strongly modified, with three thickened unbranched rays. The first unbranched anal-fin ray has segments fused and is immediately preceded by a short tegumentary keel (Fig. 21, tk). The second unbranched ray has an intermediate size between the neighboring first and third rays. Third unbranched is the longest ray forming a short rounded tip (Fig. 21, uiii); distal segments smaller, antrorsely curved (Fig. 21, ac). First branched ray bearing retrorsely curved distal segments (Fig. 21, rc). Posterior branched rays are progressively shorter, with the last branched one somewhat reduced (Fig. 21, b6). Hemal spines 15-18 interdigitate with anal-fin pterygiophores; with hemal spines 15-17 thickened in mature male, but are undifferentiated in females. The caudal-fin lobes have the same length in mature female, whereas upper lobe is slightly elongated in mature male. Distribution. Tatia dunni has a wide distributional range, occurring in the upper Amazon, Ecuador and Colombia and the central Amazon, Brazil, in Solimões and Purus rivers. It is the species of Tatia that occurs at the highest elevations as it has been recorded at 1950 m abs, in Caquetá river drainage, Cauca mountains Morelia, Colombia (Fig. 6). Remarks. Tatia dunni was placed in the synonymy T. intermedia by Mees (1974). The shared presence of white markings on dark body in both species was considered within the limits of intraspecific variation (Mees, 1974: 68). In spite of similarities in coloration, T. dunni is distinguished by its long preanal length, 70.0-75.0% SL (vs. 65.0-69.4% SL in T. intermedia) and short interorbital distance, 54.1-59.4% HL (vs. 60.1-63.6% HL in T. intermedia). The male modified anal fin differs in both species. In T. dunni the last branched ray is markedly reduced (vs. only slightly shorter than penultimate ray in T. intermedia). Material examined. 48 specimens (28.4-114.9 mm SL). Holotype. Colombia: ANSP 71705, 1 (83.3 mm SL), upper Amazonas, Morelia, Caquetá river drainage (holotype of Centromochlus dunni). Paratype. Colombia: ANSP 71706, 1 (50.1 mm SL), Alto Amazonas, Fig. 20. Neurocranium of Tatia dunni, ANSP 71706, paratype, 50.1 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. Range Mean SD N Standard length 66.1-114.5 82.5 15 Percents of standard length Body depth 15.7-26.3 19.4 2.49 15 Body width 17.8-24.7 21.5 1.57 15 Caudal peduncle depth 14.1-18.6 15.2 1.49 15 Caudal peduncle length 23.0-28.2 24.7 1.87 15 Predorsal length 29.2-36.7 31.9 1.79 15 Preanal length 70.0-75.0 72.0 1.98 15 Prepelvic length 49.2-56.1 51.7 1.96 15 Dorsal origin to pectoral origin 20.2-28.2 23.6 1.81 15 Dorsal origin to pelvic origin 27.0-33.3 29.9 2.38 15 Pectoral origin to pelvic origin 30.7-38.9 34.7 2.02 15 Prepectoral length 17.5-22.9 20.5 1.56 15 Dorsal-fin base length 7.8-12.4 10.0 1.41 15 Adipose-fin base length 6.1-12.6 9.8 1.83 15 Anal-fin base length 5.4-9.6 7.7 1.99 15 Dorsal-fin spine length 13.8-19.7 17.0 2.25 13 Pectoral-fin spine length 19.7-25.3 22.3 1.60 13 Postcleithral process lenght 15.6-21.6 16.9 2.27 15 First branched pelvic-fin ray 11.7-16.2 13.6 1.37 15 Longest anal fin ray 5.2-14.1 8.9 2.15 15 Maxillary barbel length 27.3-32.9 30.1 2.17 15 Outer mental barbel length 6.6-14.2 9.5 1.93 15 Mental barbel length 3.1-8.0 5.6 1.07 15 Head length 21.1-29.5 24.1 2.28 15 Percents of head length Head width 76.0-80.1 78.5 1.82 15 Snout depth 47.0-51.7 48.7 1.81 15 Interorbital distance 54.1-59.4 58.2 1.83 15 Left internarial width 18.3-25.5 22.1 2.10 15 Anterior internarial distance 38.3-44.8 41.7 2.16 15 Posterior internarial distance 36.1-42.0 38.6 1.75 15 Snout length 36.1-42.2 39.0 2.20 15 Orbital diameter 20.0-26.4 26.4 2.60 15 Mouth width 48.1-52.3 51.0 1.75 15 Table 6. Morphometric data for Tatia dunni. SD = standard deviation. A systematic revision of Tatia 516 Morelia, Caquetá river drainage (paratype of Centromochlus dunni). Non-type specimens. Brazil: Amazonas: CAS 52124, 3 (28.4-40.8 mm SL), Castelo Branco, lago Grande, Amazonas river; CAS 60681, 3 (81.0-97.2 mm SL), Amazon basin; INPA 3017, 1 (69.0 mm SL), Catalão, Solimões river, igarapé Madalena; INPA 18477, 3 (72.087.8 mm SL), Tupinambaranas Island; INPA 17182, 1 (91.7 mm SL), Purus river; INPA 17184, 2 (98.8-103.0 mm SL), Jari Lake, Purus river; MZUSP 44127, 1 (93.3 mm SL), Pauini. Ecuador: AMNH 58405, 3 (50.3-94.7 mm SL). AMNH 58406, 2 (66.7-70.8 mm SL), western Ecuador; FMNH 88187, 3 (66.1-84.2 mm SL), Conambo river, mouth of Shiona river, eastern Ecuador; FMNH 92007, 1 plus 1CS, (96.9 mm SL), Conambo river, mouth of Shiona river, eastern Ecuador; FMNH 92008, 1 (114.9 mm SL), Corrientes river, Napo, eastern Ecuador; FMNH 103964, 5, Zancudococha lake, Aguarico river drainage; FMNH 103965, 2, Blanco river close to Tiputini river upstream from bridge; FMNH 103966, 1, laguna Grande de Cuyabeno and Quebrada de Hormigas, Aguarico river drainage; FMNH 103967, 1, Cuyabeno river, about 1-3 km upstream of mouth of Aguarico river; FMNH 103968, 2, tributary of lower Cuyabeno river; FMNH 103969, 2, lake communicating with Lagartococha river, about 25 Km upstream from mouth of Aguarico river; FMNH 103970, 1, Aguas Negras river, about 1-2 Km upstream from bridge. Peru: CAS 158882, 1 (90.8 mm SL) (R), Ampiyacu river, near Pebas, Loreto department; CAS 158883, 1 (69.1 mm SL) (R), Chancho rivulet, near Pebas, Loreto department; CAS 158884, 1 (49.2 mm SL) (R), Yaguas Yacu, near Pebas, Loreto department; INHS 43890, 2 (48.9-77.3 mm SL), Quebrada Shushuma, Nanay river drainage, Amazon basin; USNM 124901, 1 (60.0 mm SL) (R), Shansho creek, Ampiyacu river drainage. Tatia galaxias Mees, 1974 Figs. 22-24 Centromochlus aulopygius. Pellegrin, 1899: 188 [Apuré, Venezuela]. Schultz, 1944: 240 [Venezuela]. Puyo, 1949: 97 [streams on region of Approuage]. Tatia aulopygia. Gosline, 1945: 10 [in part, Apuré]. MagoLeccia, 1967: 225 [Venezuela]. Burgess, 1989: 242, pl. 113, 114 [northeastern South America]. Tatia galaxias Mees, 1974: 86-88, fig. 23. [type locality: Quiribana rivulet, Orinoco Basin, Venezuela]. Sands, 1984: 36-37 [Venezuela]; Mees, 1988: 411-412 [Guarapiche river, Venezuela]; Burgess, 1989: 242 [Apure, Venezuela]; Franke, 1990: 20-34 [notes on reproduction]. Soares-Porto, 1998: 331-350 [citation]. Ferraris, 2003: 476 [checklist]. Lasso et al., 2004: 139 [Cataniapo, Bita, Meta, Suapure, Apure, Caura, Morichal Largo, Delta, Orinoco]. Ferraris, 2007: 77 [checklist]. Tatia intermedia. Soares-Porto, 1998: 333 [citation]. Ferraris, 2003:477 [checklist]. Lasso et al., 2004: 139 [Bita, Apure, Caroní, Orinoco]. Diagnosis. Tatia galaxias is uniquely distinguished from congeners by its well developed postcleithral process, reaching almost to a vertical through the dorsal-fin origin; a large eye, 37.0-42.9% HL (vs. 17.4-31.6% in other Tatia); and by a short snout 23.1-28.9% HL (vs. 31.2-43.6% in other Tatia). The species is also distinguished by the following combination of characteristics: narrow elliptical cranial fontanel; ribs 7 (vs. 8-11 in most other Tatia, except T. strigata with 7 ribs and T. gyrina with 5-6 ribs). Additional features useful for distinguishing T. galaxias include: nasal ossified with wide medial flanges partially sutured to lateral margin of mesethmoid; coloration variable, sides of body usually dark with light, rounded spots or dots, or sometimes uniformly pale brown; toothed prevomer in examined large adult specimens. Description. Measured adult specimens 54.2-125.6 mm SL; morphometric data presented in Table 7. Body slim, head slightly depressed dorso-ventrally. Head large, robust, outline of head in dorsal view elliptic, broader than long. Dorsal outline of trunk from dorsal-fin base to caudal peduncle gradually compressed posteriorly. Lateral profile of head from snout tip to above opercular margin slightly convex to pectoral-fin insertion. Ventral profile of head and abdomen flat. Ventral profile of body concave posterior to anal fin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended posterolaterally as well-developed fleshy rictal fold; snout margin rounded; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils larger than distance between posterior ones. Maxillary barbel reaching vertical through end of dorsal-fin; mental barbel short, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 50.0-67.0% length of outer mentals. Postcleithral process short, reaching vertical through origin of dorsal fin. Caudal peduncle deep, its depth about 14.2-18.3% SL. Rostral border of cranium with mesethmoid as long as broad; premaxilla underneath with synchondral articulation; cranial fontanel elliptical, bounded by mesethmoid and frontal (Fig. 23); nasal ossified, with medial flanges sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla small, shorter Fig. 21. Male modified anal fin of Tatia dunni, holotype, ANSP 71705, 83.3 mm SL. Left side lateral view. Abbreviations: ac, antrorsely curved denticulation; b1, branched first ray; b6, branched sixth ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 517 than autopalatine. Prevomer expanded anteriorly, with well developed arrow-shaped lateral processes, bearing small teeth attached to process in a large specimen with 85 mm SL (MCNG 25983). Jaws of equal size; premaxilla and dentary with two to three rows of conical teeth. First nuchal plate pentagonal; second nuchal plate broad, laterally concave; third nuchal plate projected laterally, with curved distal tip. Epioccipital process very small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle large. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last one largest and expanded. Seven to eight infraorbital bones in usually complete series. Rarely incompletely ossified with 5 canal bones. Infraorbital 1 thin, with short ventro-lateral process limited to anterior border of eye; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2-4 small, close to infraorbital 1. Infraorbitals 5-6 long ossified canals, bordering eye below and posteriorly. Last infraorbital much small, forming posterior orbital rim, in contact to sphenotic. Lateral line on body with ossified canal bones posteriorly to vertical through pelvic origin. Dorsal fin I,5 (n=42), dorsal-fin spine with 15-18 antrorse serrations along entire anterior margin; posterior margin smooth. Pectoral fin I,5 (n=42), pectoral-fin spine with 19-25 antrorse serrations along anterior margin; 13-17 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5 (n=42), margin rounded. Adipose fin moderate in size, origin on vertical through analfin base origin. Anal fin iii, 6-7 (n=42); anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 18-20 upper procurrent, 18-20 lower procurrent rays (n=42). Seven pleural ribs attached to consecutive vertebrae. Post-Weberian vertebrae 32-33 (n=4), rarely 30. Color in alcohol. Body usually dark brown with evenly spaced small white dots; chin with scattered pigment; underparts from chin to anus and ventrals unpigmented; pectoral fin pigmented lightly (Mees, 1974: 86). Dorsal fin with dark base and irregular spots; caudal fin usually with whitish spots irregularly distributed over lobes (Fig. 22). Color variation. Although the body usually is dark brown with whitish spots, T. galaxias may be polymorphic for color pattern, as a large array of variation regarding color is observed. Some specimens have a light brown body. Some have small roundish spots over the body and caudal fin, a common pattern in very young specimens < 40 mm SL. Some have Fig. 22. Tatia galaxias.(a) ANSP 138105, male, 64.6 mm SL. (b) ANSP 138105, female, 54.2 mm SL, El Viento rivulet, Colombia. A systematic revision of Tatia 518 caudal fin with dark tips. All distinct patterns may be found together in the same locality. Sexual dimorphism. Based on examination of gonads, T. galaxias attains sexual maturity above 54.2 mm SL. In mature females a genital papilla is not evident. A genital papilla is visible in mature male, with a long slender emergent deferent duct (Fig. 24, dd). The male anal fin is strongly modified, with the anterior rays enlarged and thickened. The first unbranched anal-fin ray have segments fused and is preceded by a tegumentary keel (Fig. 24, tk). The second unbranched ray is elongated, with an intermediate size between the neighboring first and third rays. Third unbranched plus the first branched are the longest rays, forming a pointing tip. The third unbranched ray has the distal segments antrorsely curved (Fig. 24, ac). First and second branched rays have retrorsely curved distal segments (Fig. 24, rc). The remaining branched rays are progressively shorter, with the last ray not reduced (Fig. 24, b7). Hemal spines 15-18 interdigitate with the anal-fin pterygiophores, being the hemal spines 15-17 thickened in mature males, but undifferentiated in females. The caudal-fin lobes have the same length in mature females, whereas in males the upper lobe is slightly elongated. Distribution. Endemic to the Orinoco basin in Venezuela, including Meta drainage, in Colombia (Fig. 6). Remarks. Mees (1974) described T. galaxias on the basis of its diagnostic color pattern of small white spots evenly spaced over a dark body (pattern exemplified in Fig. 22). Mees, (1974: 88) considered its coloration reminiscent of that of T. intermedia, except in T. galaxias the body is darker, the spots smaller, and the tail dark with white spots (vs. pale with dark spots and cross-bars in T. intermedia). We observed the dark body to be geographically variable in both T. galaxias and T. intermedia. In acidic black water rivers specimens of T. galaxias tend to have a darker body, when compared to those from clear water rivers. Together with the pattern of small white spots, other patterns of coloration were recognized among Orinoco specimens, such as uniformly dark and dark with white ellipsoid spots, the latter being rarest. In T. galaxias the spots are usually round, whereas in T. intermedia the spots are typically more ellipsoidal. Tatia galaxias also has a larger eye 37.0-42.9% HL (vs. 21.4-26.3% in T. intermedia) and fewer ribs, 7, and fewer vertebrae 32-33 (vs. 10 ribs and 35-36 vertebrae in T. intermedia). Tatia galaxias and T. intermedia are the only species of Fig. 23. Neurocranium of Tatia galaxias, RMNH 26493, paratype, 55.6 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n2, second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1.0 mm. Range (n=42) Mean SD N Standard length 54.2-125.6 64.7 15 Percents of standard length Body depth 16.1-22.9 19.2 1.98 15 Body width 18.8-24.8 22.3 1.35 15 Caudal peduncle depth 14.2-18.3 15.6 1.96 15 Caudal peduncle length 21.5-28.0 24.6 1.99 15 Predorsal length 28.7-38.1 32.6 1.97 15 Preanal length 64.0-69.9 66.3 1.95 15 Prepelvic length 45.6-53.2 49.5 1.87 15 Dorsal origin to pectoral origin 20.8-28.9 23.9 1.98 15 Dorsal origin to pelvic origin 25.0-29.9 27.7 1.88 15 Pectoral origin to pelvic origin 29.6-35.8 32.2 1.99 15 Prepectoral length 18.8-25.3 21.8 1.64 15 Dorsal-fin base length 7.9-12.5 10.4 1.17 15 Adipose-fin base length 5.7-14.9 11.8 1.98 15 Anal-fin base length 4.6-12.9 9.6 1.99 15 Dorsal-fin spine length 15.3-22.1 18.6 1.96 15 Pectoral-fin spine length 20.0-26.8 23.1 1.97 15 Postcleithral process length 16.1-21.3 18.4 1.48 15 First branched pelvic-fin ray 11.5-15.3 13.8 1.00 15 Longest anal fin ray 6.0-20.1 11.2 2.14 15 Maxillary barbel length 22.6-39.8 31.6 3.80 15 Outer mental barbel length 5.4-11.0 8.2 1.54 15 Mental barbel length 3.7-13.0 5.9 1.84 15 Head length 21.7-28.2 24.4 1.63 15 Percents of head length Head width 78.0-83.6 80.7 1.85 15 Snout depth 42.3-48.6 45.5 1.92 15 Interorbital distance 54.1-59.9 57.9 1.89 15 Left internarial width 18.6-28.6 22.0 1.86 15 Anterior internarial distance 40.8-48.1 44.2 1.87 15 Posterior internarial distance 39.2-45.8 42.1 1.96 15 Snout length 23.1-28.9 25.3 1.95 15 Orbital diameter 37.0-42.9 39.3 1.94 15 Mouth width 50.9-55.9 53.2 1.87 15 Table 7. Morphometric data for Tatia galaxias. SD = standard deviation. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 519 the genus bearing a toothed prevomer. Within the Auchenipteridae prevomerian teeth appear in Asterophysus batrachus, in both adults and young specimens. Ferraris (1988) considered the presence of prevomerian teeth in Tatia an aberration. In our examination of T. galaxias only a single specimen exhibited teeth. In T. intermedia, however, prevomerian teeth were found in all large specimens > 74 mm SL (n= 4). In all other large size (>100 mm SL) centromochlin species, such as Glanidium albescens,G. ribeiroi,G. melanopterum,G. leopardus,Centromochlus schultzi,C. heckelii and C. existimatus, the prevomer is edentulous. Material examined. 57 specimens (27.0-125.6 mm SL). Paratypes. CAS 6568, 4 (49.0-56.6 mm SL) and RMNH 26493, 2 (48.5-55.6 mm SL) (R), Quiribana rivulet, near Caicara, Orinoco basin (paratypes of Tatia galaxias). Non-type specimens. AMNH 58320, 2 plus 1CS, no locality, probably Venezuela. Colombia: ANSP 138104, 1 (43.4 mm SL); ANSP 138106, 1 (38.0 mm SL), Humacita farm, small stream, probably belonging to the complex of lake Mozambique, Meta river drainage; ANSP 138105, 2 (54.2-64.6 mm SL), El Viento rivulet, Finca El Viento south of Matazul. Venezuela. Amazonas: AMNH 91381, 1 (125.6 mm SL), Mavaca river; ANSP 160648, 1 (44.0 mm SL), Sipapo river above Pendare; CAS 158873, 1 (40.8 mm SL), bifurcation on Orinoco river in Tamatama beach. FMNH 103487, 2 (30.0-36.4 mm SL), Atabapo river close to Sapo island, above San Fernando de Atabapo. MCNG 25983, 1 (85.6 mm SL), Siapa river. MCNG 27966, 1 (39.3 mm SL), Orinoco river in El Tigre island. Apure: FMNH 69928, 2 (27.0-39.6 mm SL), Cinaruco river south of San Fernando de Apure; FMNH 103487, 2 (31.5-37.5 mm SL), Atabapo river upstream from San Fernando de Atabapo. INHS 60322, 2 (R), Guaritico rivulet, south of Bruzual, Apure river drainage. MCNG 7080, 1 (32.9 mm SL); MCNG 15891, 1 (43.1 mm SL), Maporal Rivulet. Bolivar: ANSP 149691, 1 (39.2 mm SL), Urbani river on road Maripas-Las Trincheras. ANSP 149973, 17 (28.8-44.4 mm SL), Quiribana rivulet near Caicara, Orinoco basin. ANSP 160571, 2 (34.1-35.5 mm SL), Los Pavones rivulet, tributary of Sipao river, near Farm Fundo Malama. CAS 158860, 2 (28.7-32.0 mm SL); CAS 158865, 3 (43.7-58.4 mm SL); CAS 158879, 1 (54.8 mm SL), Quiribana rivulet, near Caicara, Orinoco basin. MCNG 1028, 2 (33.1-34.0 mm SL), Tierra Blanca rivulet, Km 82 on road Santa Elena. MCNG 16632, 2 (43.3-64.0 mm SL), Las Claritas river Km 85 on road Santa Elena. MCNG 15595, 1 (57.0 mm SL), Sacuima river, via Caicara-Pijiguaos. MCNG 15970, 1 (39.0 mm SL), Chaviripa river. MCNG 23254, 1 (44.8 mm SL), Quebrada, close to C. Serapia del Nichare river; MZUSP 44072, 2 (68.5-72.3 mm SL), Cocniza rivulet, tributary of Orinoco river, near Caicara del Orinoco. Guarico: INHS 61870, 5 (20.5-29.5 mm SL) Guariquito river near Aguas Muertes, Parque Aguaro-Guariquito. INHS 61940, 3 (24.4-25.0 mm SL) San Bartolo river. INHS 69420, 4 (22.8-30.0 mm SL) San Bartolo river west from La Esperanza. MCNG 1914, 3 (31.4-32.5 mm SL) Aguaro river in Hato San Jose. MCNG 15001, 3 plus 1CS (25.3-29.4 mm SL) San Bartolo river, Parque Aguaro. MCNG 17137, 1 (28.3 mm SL) rivulet in Hato Batolena. MCNG 17138, 2 (25.1-32.2 mm SL) San Bartolo river, Parque Aguaro. Monagas: RMNH 30502, 1 (31.0 mm SL) Guarapiche river. USNM 265661, 1 (30.0 mm SL) Guarguapo rivulet, about 500 meters upstream from its mouth in Orinoco river, upstream from Barrancas. Tatia gyrina (Eigenmann & Allen, 1942) Figs. 2-5, 25-26 Centromochlus aulopygius. Eigenmann & Eigenmann, 1888: 157 [Cudajas (Codajás)]. Eigenmann & Eigenmann, 1890: 270 [distribution]. Eigenmann & Eigenmann, 1891: 34 [listing]. Centromochlus gyrinus Eigenmann & Allen, 1942: 118, pl.5 fig. 4 [type locality: Peru, Iquitos, brook near Itaya river]. Gosline, 1945: 10 [listing]. Fowler, 1945a: 62 [Iquitos]; Fowler, 1945b: 112 [listing]; Fowler, 1951: 462, fig. 491 [literature compilation]. Centromochlus creutzbergi Boeseman, 1953: 7, fig. 1c [type locality: Djaicreek (Djao stream)]. New synonym. -Hoedeman, 1957:151, fig. 8 [Coropina stream near Republiek].- Rössel, 1962: 30 [no locality].-Hoedeman, 1968: 148 [Suriname]. Tatia gyrina. Mees, 1974: 74-75 [notes on holotype and distribution]. Ortega & Vari, 1986:14 [reference]. Burgess, 1989:242 [reference]. Soares-Porto, 1995:205 [citation]. Soares-Porto, 1998: 333 [citation]. Ferraris, 2003:477 [checklist]. Ferraris, 2007: 77 [checklist]. Tatia creutzbergi. Mees, 1974: 77-80, fig. 18 [notes and distribution, northern Suriname lowlands and Cudajas (=Codajás), Brazil]. Sands, 1984: 40 [listing]. Mees, 1985: 241 [northern Suriname]. Mees, 1988: 410 [Para stream and Kaboeri stream, Suriname]. Burgess, 1989:242 [reference]. Soares-Porto, 1995:205 [citation].Chang & Ortega, 1995:4 [reference]. Soares-Porto, 1998: 333 [citation]. Ferraris, 2003:476 [checklist]. Ferraris, 2007: 77 [checklist]. Diagnosis. Tatia gyrina is distinguished from all other species of Tatia by its reduced mesethmoid, wider than long, (mesethmoid length 12.1-15% HL; width 17.2-19% HL); lower jaw slightly protruding beyond upper; nasal ossified, tubular, not sutured to mesethmoid; third nuchal plate reduced (Fig. 3, n3); small prevomer, with short rostro-lateral process; elongate postcleithral process, sometimes as long as head length; ribs 5-6 (vs. 7-11 in other Tatia); and vertebrae, 29-30 Fig. 24. Male modified anal fin of Tatia galaxias, MCNG 25983, 85.6 mm SL. Left side lateral view. Abbreviations: ac, antrorsely curved denticulation; b1, branched first ray; b7, branched seventh ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1.0 mm. A systematic revision of Tatia 526 nus. It occurs in the upper reaches of the Araguaia, Tocantins, Xingu, and Capim rivers, tributaries of the lower Amazon of Brazil, northwards to the Suriname coastal rivers and the Essequibo river in Guyana (Fig. 6). Remarks. Recognition of T. intermedia remained difficult for a long time. Mees (1974: Fig. 11) mistakenly associated the specimens from Suia Missu river in Mato Grosso, Brazil, as T. aulopygia. Mees’ specimens were young, bearing small spots over the body, and their coloration conforms with that observed for other T. intermedia.Tatia intermedia and T. aulopygia are compared under the redescription of T. aulopygia. The pectoral-fin spine with transverse bands was considered distinctive for T. intermedia by Soares-Porto (1998). Herein this feature is considered variable, as in some populations the spine is barred, some not. Soares-Porto (1998: 341) considered a barred spine as a derived feature shared between T. intermedia and T. brunnea, but such a condition varies intraspecifically in both species. Some large T. intermedia may be superficially similar to large T. dunni, as both species may have faint light spots on the sides of the body. In spite of this similarity, T. intermedia differs by having a short postcleithral process, not reaching the vertical through the dorsal-fin origin (vs. long, reaching vertical through dorsal-fin origin in T. dunni); a toothed prevomer in large specimens (vs. edentulous in large T. dunni); and a male modified anal fin with 3-5 elongate antrorse curved segments (vs. 1-3 short antrorse curved segments in T. dunni). Material examined. 57 specimens (13.1-91.2 mm SL). Syntype. NMW 47355, 1 (R), Brazil: Pará: Marabitanos (syntype of Centromochlus intermedius). Brazil: Amapá: MNRJ 12132, 1 (66.0 mm SL), Brazil: Amapá: Maruanum river, tributary of Matapi river, Macapá. MNRJ 12133, 1 (31.9 mm SL) and MNRJ 12134, 9 (40.265.1 mm SL), Brazil: Amapá: Aporema river in Fazenda Modelo do Aporema, tributary of Araguari river. Brazil: Goiás: MNRJ 5896, 2 (28.0-66.6 mm SL), Brazil: Goiás: Araguaia river, Aruanã (older Leopoldina). Brazil: Mato Grosso: MZUSP 44256, 2 (29.5-35.2 mm SL), Brazil: Mato Grosso: lake Ipavu, Parque Nacional do Xingu. RMNH 26491, 2 (20.3-31.6 mm SL), Brazil: Mato Grosso: Suia Missu river (=suiá miçú). Brazil: Pará: INPA 2978, 1 (45.4 mm SL), igarapé Tucuruizinho, Tocantins river. INPA 11076, 1 (84.7 mm SL), Tocantins river. INPA 21006, 2 (50.4-56.5 mm SL), Trombetas river. MZUSP 9332, 1 (37.3 mm SL), igarapé Ribeira, near Badajós. MZUSP 43250, 15 (19.0-40.0 mm SL), lake Bernardino, near Badajós, Capim river; Km 97. MZUSP 44125, 2 (24.1 mm SL); MZUSP 44255, 5 (29.6-65.3 mm SL), Vila Santana, Capim river. MZUSP 44257, 7 (33.0-48.4 mm SL) and MZUSP 47503, 1, CS, igarapé Caranandena, Capim river. MZUSP 47507, 20 (17.2-49.0 mm SL), lake Maria Preta, Capim river; MZUSP 47508, 1 (40.0 mm SL), igarapé Jari-Mirim, Capim river; MZUSP 50860, 1 (17.2 mm SL), igarapé Canteiro, near Vila Santana, Capim river. MZUSP 44254, 3 (13.1-16.4 mm SL), igarapé Oxipucu, Mocajuba, Tocantins river. MCZ 46032, 1 (20.8 mm SL), Arari river. MZUSP 50861, 1 (24.2 mm SL), Arari river, Arari waterfalls, Marajó island. MCZ 46130, 3 (37.3-40.6 mm SL); MZUSP 43139, 5 (35.2-42.0 mm SL); MZUSP 47504, 1 CS, and RMNH 26492, 1 (40.0 mm SL) igarapé Paracuri, near Icoaraci, Belém. Tocantins: INPA 20042, 1 (58.2 mm SL) Araguari river, locality of Ariranhas in Caseara district. MZUSP 41838, 1 (55.5 mm SL), córrego Jóia, Santa Rita do Araguaia. MZUSP 41422, 1 (57.7 mm SL), Córrego Jacaré, Santa Rita do Araguaia. Suriname. RMNH 26195, 2 (51.355.1 mm SL); RMNH 26199, 12 (38.5-50.0 mm SL), Sipaliwini. RMNH 26201, 1 (27.4 mm SL), stream near aerodrome Käysergebergte. ZMA 105.791, 3 (51.2-74.2 mm SL) (R), stream on left margin of Suriname river, 2,5 km north from Botopasi Village, Brokopondo district. Guyana. AMNH 12947, 1 (72 mm SL), Wismar. AMNH 17643, 1 (91.2 mm SL), Cuyuni river. CAS 24798, 1 (49.3 mm SL) Wismar river, Demerara, Demerara basin. Tatia meesi, new species Fig. 30-32 Holotype. INHS 99772 (44.3 mm SL), Guyana, Potaro-Siparuni: lower Potaro river (Essequibo river Drainage), Waratuk cataract, 05º15’31.9”N 59º24’01.0”W, 26 Oct 1998, L. M. Page, M. H. Sabaj, J. M. Armbruster, M. Hardman, J. H. Knouft & W. S. Prince. Paratypes. Guyana, Potaro-Siparuni: AUM 28140, 14 (27.3-43.1 mm SL); INHS 49549, 9, (1 CS, 43.3 mm SL) (30.3-46.6 mm SL), MBML 2046, 3 (32.2-42.6 mm SL), and MNRJ 28720, 3, (1 CS, 34.0-39.5 mm SL) all collected with the holotype. Fig. 28. Neurocranium of Tatia intermedia, MZUSP 44255, 65.5 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 527 Diagnosis. Tatia meesi is uniquely distinguished from congeners by its coloration: dorsal surface of body, back and upper sides dark-brown sometimes with depigmented area around adipose fin. Cranial fontanel with two narrow openings: anterior one between mesethmoid and frontal and posterior one limited to frontal (Fig. 31). The fontanel apertures are separated from each other through an orbitosphenoid suture beneath frontal. The new species also is distinguished from congeners by a combination of characteristics: nasal ossified as tube, with narrow lateral flange not sutured to mesethmoid; pectoral fin I,4; caudal-fin lobes are the same length in both adult females and males. An additional feature useful for distinguishing T. meesi has the smaller adult size, less than 50 mm SL. Description. Measured adult specimens 39.5-46.6 mm SL; morphometric data presented in Table 10. Body slim, head slightly depressed dorso-ventrally. Head robust, outline of head in dorsal view somewhat elliptic, broader than long. Trunk from dorsal-fin base to caudal peduncle becoming gradually compressed laterally. Lateral profile of head from snout tip to opercular margin slightly convex until pectoralfin insertion. Ventral profile of head and abdomen almost straight. Ventral profile of body gently curved, concave behind anal-fin origin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended postero-laterally as well-developed fleshy rictal fold; snout margin rounded, in dorsal view; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils proportionally same as distance between posterior ones. Maxillary barbel short, extending close to posterior tip of postcleithral process; mental barbel short, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 51.0-64.0% length of outer mentals. Postcleithral process long almost reaching vertical through middle or end of dorsal fin. Caudal peduncle moderately deep, depth about 10.4-12.3 SL. Rostral border of cranium with mesethmoid approximately as long as broad; premaxilla underneath with synchondral articulation; elliptical cranial fontanel, with two narrow openings: anterior one between mesethmoid and frontal and posterior one limited to frontal. Fontanel apertures separated to each other by suture beneath frontal, along orbitosphenoid (Fig. 31). Nasal ossified, tubular, with narrow medial flanges, not sutured to mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla about same size of autopalatine; prevomer expanded anteriorly , with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary narrow with two or three rows of conical teeth. First nuchal plate very short, pentagonal; second nuchal plate slightly concave along lateral margins; third nuchal plate curved, projected laterally, with broad tip. Epioccipital process very small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as short canal bone. Five slender branchiostegal rays articulated with hyoid arch: three or four with anterior ceratohyal and two with posterior ceratohyal; last two flattened. Basibranchial 2 forming osseous rod with a broad cartilaginous anterior tip, separated from shorter basibranchial 3. Five infraorbital bones in incomplete series. Infraorbital 1 thin with short ventro-lateral process; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and two posterior ossicles much close to sphenotic, forming posterior orbital rim. Lateral line on body with ossified canal bones only close to head. Dorsal fin I,5, dorsal-fin spine with 9-11 antrorse serrations along entire anterior margin, posterior margin smooth. Pectoral fin I,4, pectoral-fin spine with 15-18 antrorse serrations along anterior margin; 10-11 retrorse serrations along posterior margin; serrations along both margins progressively larger toward spine tip. Pelvic-fin i,5, margin rounded. Adipose fin small, origin on vertical through end of anal-fin base. Anal fin iii,7; anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin deeply forked, lobes with pointed tips, 8+9 principal rays, 5-8 upper procurrent, 5-6 lower procurrent rays. Pleural ribs 9 attached to consecutive vertebrae. Post-Weberian vertebrae 34 (n=2). Color in alcohol. Dorsal surface of body, back and upper sides dark-brown sometimes with depigmented area around adipose fin. Lips and anterior nostril whitish. Head pigmentation pale, with posterior nuchal plates lighter. Lower sides and ventral surfaces whitish. Dorsal spine dark, subsequent rays darker only on its bases. Paired, anal and adipose fins unpigmented. Caudal-fin base with chromatophores becoming progressively more widely spaced, with hyaline lobes and tips. Fig. 29. Male modified anal fin of Tatia intermedia, MZUSP 44255, 65.5 mm SL. Left side lateral view. Abbreviations: ac, antrorsely curved denticulation; b1, branched first ray; b6, branched sixth ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1.0 mm. A systematic revision of Tatia 528 Sexual dimorphism. Based on examination of gonads, T. meesi attains sexual maturity above 39.5 mm SL. A genital papilla is not evident in females. The genital papilla of mature male is visible, with a short deferent duct. Adult male anal fin (Fig. 32) is strongly modified with a pointed tip. First unbranched anal-fin ray thickened. Second unbranched ray with a sharp tip curved towards the third unbranched ray, but not prolonged until the fin tip (Fig. 32, uii). Third unbranched ray is the longest one, forming a narrow fin tip, with distal segments gently curved (Fig. 32, uiii). First, second and third branched anal-fin rays are progressively shorter and curved towards the fin tip. Posterior branched rays normally developed; last ray not reduced (Fig. 32, b7). The caudal fin lobes have about same length in both adult males and females. Distribution. Known only from type locality in the Essequibo basin, Guyana (Fig. 6). Etymology. The specific name honors Dr. Gerloff F. Mees, for his significant contributions to our knowledge of the genus Tatia, especially with regards to the species of the Guyana shield. Remarks. The Waratuk cataract, the type locality of T. meesi, consists of rapidly flowing water over huge boulders. At the base of the cataract is a large pool and backwater area with a substrate of sand, gravel and rubble over bedrock give shelter to some catfish species, including the tiny T. meesi (L. Page, pers. comm.). Among Tatia, subdivided fontanel apertures, with two openings separated to each other by orbitosphenoid suture is observed only in T. meesi. Dissection of alcoholic specimens confirmed the presence of an anterior and posterior fontanel. The orbitosphenoid is the place for origin of the facial mandibular muscle adductor arcus palatini.Tatia meesi has some features that are uncommon within the genus such as a tubular nasal bone and caudal-fin lobes of equal size in both males and females. It shares with T. gyrina a low number of canalicular infraorbitals and a low number of branchiostegal rays. It is distinct from T. intermedia, the only congener inFig. 30. Tatia meesi.(a) holotype, INHS 99772, male, 44.3 mm SL. (b) paratype, INHS 49549 , female, 46.6 mm SL, Essequibo river, Guyana. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 529 habiting the Essequibo basin, due to a cranial fontanel with two openings (vs. single opening in T. intermedia); nasal tubular, rod-like, not sutured to mesethmoid (vs. with lateral bony flanges, sutured to mesethmoid in T. intermedia); adult specimens small sized, less than 50 mm SL (vs. large adult size, more than 50 mm SL). The color pattern, consisting of small chromatophores concentrated mainly on dorsolateral part of body in T. meesi, resembles superficially the pattern in T. boemia. In T. meesi, however, the caudal fin is hyaline vs. with small spots in T. boemia. Tatia neivai (Ihering, 1930) Fig. 33-35 Tatia intermedia. Miranda Ribeiro, 1918: 734 [Piquete & Piracicaba, São Paulo]. Fowler, 1951: 470 [literature compilation]. Miranda Ribeiro, 1962: 10 [reference]. Glanidium neivai Ihering, 1930: 99, pl. 13, fig. 1 [type locality: Piracicaba river, Piracicaba, São Paulo]. Gosline, 1945: 11 [listing]. Miranda Ribeiro, 1962: 3 [reference]. Tatia neivai. Mees, 1974: 71-74, fig. 16 [notes and distribution]. Sands, 1984: 42 [listing]. Burgess, 1989: 242, pl. 108 [reference]. Soares-Porto, 1998: 333 [citation]. Britski et al., 1999: 113 [Pantanal Mato-Grossense]. Casatti et al., 2001:5 [upper Paraná river]. Nakatani et al., 2001: 248 [larval development]. Ferraris, 2003:477 [check list]. Veríssimo et al., 2005: 7 [Manso river]. Ferraris, 2007: 77 [check list]. Tatia cf. aulopygia. Mees, 1988: 409 fig. 1 [Paraguay]. Burgess, 1989:242 [reference]. Diagnosis. Tatia neivai is distinguished from other species of Tatia by its unique color pattern with scattered small white spots over the sides of the body and the caudal fin with dark vertical bars. The species is also distinguished by the following combination of characters: third nuchal plate broad, with short lateral projection, and post-Weberian vertebrae alternatingly ribbed and unribbed. Additional features useful for distinguishing the species include: caudal-fin lobes of equal length in mature females, upper lobe more elongated in mature males; 31-33 post-Weberian vertebrae. Description. Measured adult specimens 48.1-82.1 mm SL; morphometric data presented in Table 11. Body slim, head slightly depressed dorso-ventrally. Head large, robust, dorsal profile of head elliptic, broader than long. Dorsal outline of trunk from dorsal-fin base to caudal peduncle gradually Holotype Range Mean SD N INHS 99772 (n=10) Standard length 44.3 39.5-46.6 43.6 10 Percents of standard length Body depth 19.4 19.4-22.5 20.7 1.01 10 Body width 19.2 18.3-20.2 19.2 0.58 10 Caudal peduncle depth 12.0 10.4-12.3 11.4 0.66 10 Caudal peduncle length 28.0 24.5-28.1 27.0 1.41 10 Predorsal length 30.5 28.8-34.9 31.7 1.87 10 Preanal length 71.3 62.2-71.3 65.1 3.08 10 Prepelvic length 49.9 48.1-51.5 49.7 1.12 10 Dorsal origin to pectoral origin 24.4 22.3-25.5 23.9 1.25 10 Dorsal origin to pelvic origin 28.2 28.1-32.6 30.4 1.69 10 Pectoral origin to pelvic origin 30.0 30.0-35.4 32.8 1.37 10 Prepectoral length 19.9 18.4-22.1 19.8 1.04 10 Dorsal-fin base length 10.6 8.4-10.9 9.8 0.87 10 Adipose-fin base length 8.1 8.1-10.4 9.1 0.84 10 Anal-fin base length 4.7 4.7-10.5 8.4 1.88 10 Dorsal-fin spine length 19.0 14.0-19.0 16.4 1.52 10 Pectoral-fin spine length 25.3 20.2-25.3 21.9 1.50 10 Postcleithral process lenght 19.2 18.7-22.0 20.0 1.01 10 First branched pelvic-fin ray 13.8 11.4-14.5 13.0 1.13 10 Longest anal fin ray 8.4 7.4-12.6 9.5 1.71 10 Maxillary barbel length 36.1 32.2-39.6 35.8 2.36 10 Outer mental barbel length 9.3 7.1-10.5 9.3 1.07 10 Mental barbel length 4.5 4.3-5.8 5.0 0.54 10 Head length 24.6 23.0-27.4 24.6 1.14 10 Percents of head length Head width 70.6 67.3-74.7 71.0 2.44 10 Snout depth 40.4 40.4-44.8 42.7 1.81 10 Interorbital distance 55.0 51.8-56.6 54.7 1.51 10 Left internarial width 23.9 21.7-26.1 23.7 1.57 10 Anterior internarial distance 40.4 36.9-40.4 38.7 1.20 10 Posterior internarial distance 38.5 36.9-40.6 38.7 1.18 10 Snout length 36.7 34.6-39.6 37.4 1.96 10 Orbital diameter 23.9 19.7-27.4 23.9 1.87 10 Mouth width 51.4 47.2-53.3 49.5 1.54 10 Table 10. Morphometric data for Tatia meesi. SD = standard deviation. Fig. 31. Neurocranium of Tatia meesi, new species, INHS 49549, paratype, 43.3 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. A systematic revision of Tatia 530 compressed posteriorly. Lateral profile of head from snout tip to above opercular margin slightly convex until pectoral-fin insertion. Ventral profile of head and abdomen flat. Ventral profile of body concave posterior to anal fin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended posterolaterally as well-developed fleshy rictal fold; snout margin rounded; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils slightly larger than distance between posterior ones. Maxillary barbel moderate in size, extending to posterior tip of postcleithral process, sometimes longer; mental barbel arranged in arc along ventral surface of jaw, tips not reaching pectoral-fin base; inner mental barbel about 60.0-70.0% length of outer mentals. Postcleithral process well developed, almost reaching vertical through middle of dorsal fin. Caudal peduncle moderately deep, its depth about 13.6-14.8% SL. Rostral border of cranium with mesethmoid as broad as long; premaxilla underneath with synchondral articulation; cranial fontanel narrow, elliptical, bounded by mesethmoid and frontal (Fig. 33); nasal ossified, with short medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla small, shorter than autopalatine; prevomer expanded anteriorly, with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with three to four rows of conical teeth. First nuchal plate short, somewhat elliptical; second nuchal plate laterally concave, partially in contact with supraoccipital in some specimens; third nuchal plate relatively straight, projected laterally. Epioccipital process small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as a very short canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last one largest and expanded. Five infraorbital bones in incomplete series. Infraorbital 1 broad, with short developed ventro-lateral process around anterior border of eye; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and by three posterior canal bones forming posterior orbital rim. Lateral line on body with ossified canal bones limited to head. Dorsal fin I,4-5, rarely I,4 (n=25); dorsal-fin spine with 1215 antrorse serrations along entire margin; posterior margin smooth. Pectoral fin I,4-5, rarely I,5 (n=25); pectoral-fin spine with 19-24 antrorse serrations along anterior margin, small serrations close to spine base; 13-17 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5 (n=25), margin rounded. Adipose fin short, origin on vertical through end of anal-fin base. Anal fin iii, 6-7, rarely iii,6 (n=25); anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 19-21 upper procurrent, 19-20 lower procurrent rays (n=25). Seven or nine pleural ribs attached to consecutive vertebrae plus one attached to 9th or 11th vertebrae. The 8th or 10th vertebrae correspond to gap, with no ribs attached. Ribs progressively small anteroposterioly. Post-Weberian vertebrae 31-33 (n=4). Color in alcohol. Color pattern usually with scattered small white spots over lateral sides of body mainly distributed over ventrolateral parts. Dorsal spine usually with transverse bands; pectoral-fin spine not pigmented. Caudal fin with irregular dark vertical bars. Posterior nuchal plates somewhat pale. Lips and nostrils whitish. Ventral portion of head around chin light brown. Color variation. Regional variation in coloration was observed regarding specimens from the upper Paraná river immediately above the Sete Quedas waterfalls (MHNG 2355.92). These specimens have a dark body coloration, with only a few white spots ventrally, and a caudal fin with vertical bars. Some specimens from the upper Paraguay river in the Pantanal of Mato Grosso are light brown over dorsal parts of the body, with scatteredspots along ventrolateral parts of body, and with a vertically barred caudal fin. Sexual dimorphism. Based on examination of gonads, T. neivai attains sexual maturity above 48.1 mm SL. A genital papilla is not evident in females. The genital papilla of mature male is visible, with a short deferent duct. Male anal fin (Fig. 35) is modified with the three unbranched and first branched rays enlarged and thickened. First unbranched ray is nonsegmented, and immediately preceded by a tegumentary keel (Fig. 35, tk). The second unbranched ray is elongated, coalescing towards fin tip. The third unbranched and first branched rays are the longest, forming a short fin tip. The third unbranched ray has two antrorsely curved distal segments (Fig. 35, al). The first branched ray has four or five Fig. 32. Male modified anal fin of Tatia meesi, INHS 49549, paratype, 43.3 mm SL. Left side lateral view. Abbreviations: b7, branched seventh ray; dd, deferent duct; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 531 retrorsely curved distal segments (Fig. 35, rl).The posterior branched rays become progressively shorter, with the last ray not reduced (Fig. 35, b7). Hemal spines 14-17 are interdigitating with the anal-fin pterygiophores. The hemal spines 15-17 are thick in mature males, but undifferentiated in females. The male upper caudal-fin lobe is slightly elongate, about 15.0% longer than the lower lobe, whereas in mature females there are equal lobes. Distribution. Tatia neivai occurs in the upper Paraguay river, in the Pantanal of Mato Grosso, Brazil, upper Paraná river, and upper Paraíba do Sul river (Fig. 6). It is recorded from several tributaries of the upper Paraná river, Brazil, such as the Grande river in Minas Gerais, the Tietê and Paranapanema rivers in São Paulo, and the Tibagi river in Paraná. In the upper Paraíba do Sul river the species was recorded from Piquete, São Paulo State. The single record from the São Francisco river is uncertain (MZUSP 3801) because the locality data are dubious. Remarks. Tatia neivai was observed in semi-lotic environments. Some of these catfishes were found hidden within marginal vegetation or were captured inside crevices of submersed trunks (O. Shibatta pers. comm.). Tatia neivai was described based on a single specimen from the Piracicaba river. The holotype is lost, but Ihering (1930: pl. 13) illustrated the specimen as having irregularly scratched color pattern on the sides of the body and the caudal fin with dark vertical bars. This color pattern distinguishes T. neivai from most Tatia species, except some T. aulopygia. Variation in coloration may occur among populations, but the caudal fin is always barred, and sometimes resembles that of T. aulopygia. In spite of this similarity, T. neivai and T. aulopygia can be distinguished on the basis of proportional measurements, the size of cranial fontanel (bounded by mesethmoid and frontal in T. neivai vs. restricted to frontal in T. aulopygia); the modified anal fin of adult males (distal margin continuous, without notch in T. neivai vs. notched in T. aulopygia) and the post-Weberian vertebrae (31-33 in T. neivai vs. 38-39 in T. aulopygia). Material examined. 60 specimens (23.1-82.1mm SL). Brazil: Goiás: NUPELIA unnumbered, 1, (58.4 mm SL), Corumbá river, near Ipameri, Pires do Rio District. Mato Grosso do Sul: MZUSP 35882, 1 (26.6 mm SL), Piquiri river, Santo Antônio do Paraíso farm, Itiquira; MZUSP 36364, 2 (27.7-46.8 mm SL), Corixão, Capão Grande, Nhecolândia, Corumbá; MZUSP 42145, 2 (23.6-33.9 mm SL), lake about 25 Km from Poconé, on road to Porto Cercado. Paraná: MZUEL 206, 1 (56.0 mm SL); MZUEL 207, 1 (53.7 mm SL); MZUEL 1098, 1 (63.5 mm SL), Tibagi river, município de Sertanópolis. Minas Gerais: MNRJ 28722, 2 (61.1-76.4 mm SL), Grande river, upstream from Porto Colombia dam. São Paulo: MZUSP 1993, 1 (62.1 mm SL), Piquete; MZUSP 2000, 1 (54.4 mm SL), Piracicaba river; MZUSP 35360, 1 (62.3 mm SL), Araguá river, Botucatu; MZUSP 42569, 2 (58.2 mm SL), Piracicaba river, Piracicaba; MZUSP 42570, 1 CS Fig. 33. Tatia neivai.(a) MHNG 2355.92, male, 51.6 mm SL. (b) MHNG 2355.92, female, 53.3 mm SL, Yuguyry stream, Paraguay. A systematic revision of Tatia 532 (60.5 mm SL), lake on Atibaia river, near Jaguariuna; MZUSP 45099, 1 (48.9 mm SL), Tietê river, Itápolis; MZUSP 46009, 1 (56.0 mm SL), Corumbataí river, Corumbataí; MZUSP 46855, 2 (23.1-41.0 mm SL), Pardo river, near Guaíra; MZUSP 47505, 7 (53.1-62.1 mm SL), ilha Solteira, Paraná river, Ilha Solteira dam. Paraguay: MHNG 2159.45, 1 (56.7 mm SL), Itapua: Tembey river. MHNG 2353.30, 1 (48.0 mm SL), salto Pirareta, La Cordillera. MHNG 2355.92, 12 (50.7-63.7 mm SL), Caaguazu: Yuguyry stream, about 17 Km south of Yhu. MHNG 2430.19, 1 (R) (76.1 mm SL), lake on Iguazu river, upper Paraná. MHNG 2480.48, 1 (82.1 mm SL). MHNG 2480.49, 1 (43.6 mm SL), Canindeyú: Salto Guaira, Itaipu lake. MHNG 2537.73, 8, 1 CS, (37.2-46.6 mm SL), Tagatija-mi river, about 30 Km east from Puerto Max; UMMZ 206602, 3 (29.6-30.4 mm SL), Aguaray river, San Pedro; USNM 249826, 1 (54.5 mm SL), Canindeyú: Carapa river, above waterfalls, old road from Stroessner to Guaira; ZMA 116.801, 1 (R) (66.2 mm SL), Itapua: Tembey river, 4 Km above cataracts. Tatia nigra, new species Fig. 36-39 Holotype. INPA 12291 (116.8 mm SL), Brazil, Amazonas: Uatumã river, approximate coordenates 02o14’35”S 58 o49’58”W, Oct 1983, Ichthyology INPA team. Paratypes. Brazil, Amazonas: INPA 25501, 1 (107.3 mm SL), collected with the holotype; INPA 11073, 1 (93.7 mm SL); INPA 11075, 1 (113.5 mm SL); INPA 11081, 6 (86.6-107.8 mm SL); MNRJ 32024, 1 plus1 CS (97.0-98.2 mm SL), Uatumã river, Samaúma lake, Presidente Figueiredo; INPA 12296, 1 (72.0 mm SL) Uatumã river, igarapé Miriti. Pará: MNRJ 12358, 3 (70.0-82.3 mm SL) Trombetas river, Porto Trombetas. Diagnosis. Tatia nigra is uniquely distinguished from congeners by having dark brown body color (Fig. 36) and short postcleithral process about 60.0% HL (vs. more than 80.0% HL in other Tatia). Additional features useful for distinguishing T. nigra include: postcleithral spine not reaching vertical through origin of dorsal fin; nasal with well developed medial flanges; 32 vertebrae. Description. Measured specimens 70.0-116.8 mm SL; morphometric data presented in Table 12. Body deep, head depressed dorso-ventrally. Outline of head in dorsal view almost rectangular, slightly broader than long. Trunk from dorsal-fin base to caudal peduncle becoming gradually compressed laterally. Lateral profile of head from snout tip to opercular margin convex until pectoral-fin insertion. Ventral profile of head and abdomen slightly convex. Ventral profile of body concave behind anal-fin origin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended posterolaterally as a well-developed fleshy rictal fold; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils larger than distance between posterior ones. Maxillary barbel of moderate size, extending well beyond posterior tip of postcleithral process, reaching vertical line tangent to origin of dorsal fin; mental barbel short, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 54.0-65.0% length of outer mentals. Postcleithral process short, almost reaching vertical through middle nuchal plates. Caudal peduncle deep, depth about 14.4-17.0% SL. Fig. 34. Neurocranium of Tatia neivai, MZUSP 42570, 60.5 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. Fig. 35. Male modified anal fin of Tatia neivai, MZUEL 206, 56.0 mm SL. Left side lateral view. Abbreviations: ac, antrorsely curved denticulation; b7, branched seventh ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1.0 mm. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 533 Cranium with mesethmoid as long as broad; premaxilla underneath with synchondral articulation; elliptical narrow concavity for cranial fontanel, opening bounded by mesethmoid and frontal (Fig. 37); nasal ossified, with wide medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla about same size of autopalatine; prevomer expanded anteriorly with well developed arrowshaped lateral processes; jaws of equal size; premaxilla and dentary with three to four rows of conical teeth. First nuchal plate somewhat pentagonal; second nuchal plate concave along lateral margins; third nuchal plate curved, projected laterally, with small tip. Epioccipital process very small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as short canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last two flattened and expanded. Basibranchial 2 forming osseous rod with a broad cartilaginous anterior tip, separated from shorter basibranchial 3. Five infraorbital bones in incomplete series. Infraorbital 1 broad, with short ventro-lateral process; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1; infraorbital 3 elongate, followed by short non-ossified portion of canal. Posterior three canal bones forming posterior orbital rim. Lateral line on body with ossified canal bones only close to head. Dorsal fin I,5 (n=12); dorsal-fin spine with 19-22 antrorse serrations along entire anterior margin; posterior margin smooth. Pectoral fin I,5 (n=12); pectoral-fin spine with 28-31 antrorse serrations along anterior margin; 19-21 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5 (n=12), margin rounded. Adipose fin small, origin on vertical through end of anal-fin base. Anal fin iii,7 (n=12); anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, upper lobe slightly elongated in comparison to lower lobe, 8+9 principal rays, 17-19 upper procurrent, 17-20 lower procurrent rays (n=12). Pleural ribs 10 attached to consecutive vertebrae. Post-Weberian vertebrae 32 (n=1). Color in alcohol. Tatia nigra dark colored in large adult specimens. Dorsal mid-line and dorsolateral parts of body dark brown, as well as dorsal surface of head, nuchal shield, dorsal fin and adipose fin (Fig. 36). Body progressively paler towards ventral parts. Ventral portion of head around chin, lips and anterior nostrils light brown. Belly whitish to origin of pelvic fin. Pectoral, pelvic and anal fins light brown. Caudal fin dark brown. Sexual dimorphism. Tatia nigra attains sexual maturity above 80.0 mm SL. The mature females have a small intumescent genital papilla. Male genital papilla is formed by a thick skin flap around a slender emergent deferent duct. Male modified anal fin (Fig. 38) has three unbranched and first branched rays enlarged and thickened. The first unbranched anal-fin ray is immediately preceded by a tegumentary keel (Fig. 38, tk). The second unbranched ray has an intermediate size between the neighboring first and third rays. Third unbranched is the longest ray, slightly curved towards fin tip; bearing smaller antrorsely curved distal segments (Fig. 38, ac). First branched ray is slightly curved towards the fin tip. First and second branched rays have retrorsely curved distal segments (Fig. 38, rc). Posterior branched rays are progressively shorter; with the last ray not reduced (Fig. 38, b7). Caudal-fin lobes of both analyzed mature females and males have the upper lobe elongated. Six mature males of T. nigra with a modified anal fin were examined. In two of these males the modified anal fin is laterally curved and spoon shaped (Fig. 39), suggesting reproductive modification for internal inseminating. Distribution. Known from the central Amazon, in the Uatumã and Trombetas river drainages, northern tributaries of the Amazon river (Fig. 6). Etymology. The specific name nigra, is a Latin reference to the dark color pattern of this species. Range Mean SD N Standard length 48.8-82.1 58.4 9 Percents of standard length Body depth 18.1-24.6 20.3 1.98 9 Body width 17.5-21.8 19.8 1.00 9 Caudal peduncle depth 13.6-14.8 14.1 1.10 9 Caudal peduncle length 20.9-28.1 24.7 1.83 6 Predorsal length 26.8-36.4 32.1 1.68 9 Preanal length 64.9-74.8 69.3 2.84 9 Prepelvic length 50.0-56.5 52.5 1.80 9 Dorsal origin to pectoral origin 19.7-26.6 23.0 1.45 9 Dorsal origin to pelvic origin 27.3-34.3 31.1 1.97 9 Pectoral origin to pelvic origin 30.6-38.2 35.0 1.97 9 Prepectoral length 16.1-23.7 20.3 1.73 9 Dorsal-fin base length 8.0-11.8 10.2 0.93 9 Adipose-fin base length 7.4-13.8 11.0 1.80 9 Anal-fin base length 2.9-12.3 7.0 2.73 9 Dorsal-fin spine length 13.4-21.2 17.8 1.99 8 Pectoral-fin spine length 22.0-27.1 23.6 1.66 9 Postcleithral process lenght 13.2-22.1 19.7 1.99 9 First branched pelvic-fin ray 8.6-15.1 12.8 1.30 9 Longest anal fin ray 5.7-10.3 8.3 1.31 9 Maxillary barbel length 30.0-34.9 32.1 1.94 9 Outer mental barbel length 6.9-11.1 8.9 1.26 9 Mental barbel length 4.8-11.4 6.3 1.42 9 Head length 21.3-26.7 23.4 1.42 9 Percents of head length Head width 70.8-76.9 74.5 1.99 9 Snout depth 52.1-57.7 54.8 1.96 6 Interorbital distance 53.0-58.7 55.7 1.88 9 Left internarial width 20.8-28.5 24.3 1.94 6 Anterior internarial distance 34.1-39.6 37.4 1.78 6 Posterior internarial distance 33.5-39.7 36.7 1.98 9 Snout length 33.0-38.8 37.4 1.98 9 Orbital diameter 20.0-24.2 22.0 1.84 9 Mouth width 47.9-52.9 50.2 1.80 9 Table 11. Morphometric data for Tatia neivai. SD = standard deviation. A systematic revision of Tatia 534 Remarks. Tatia nigra has well-developed lateral ornamented medial flanges of bone on the nasal, but not as large as the flanges observed in T. aulopygia. The expanded nasal with medial flanges partially sutured to mesethmoid was recognized as a derived feature for the genus (Soares-Porto, 1998), and was also observed in T. aulopygia, T. boemia, T. dunni, T. neivai, T. strigata, and adult specimens of T. intermedia. Female genital papilla in T. nigra is not a common condition within the genus. The only other Tatia with female genital papilla is T. gyrina. The intumescent female genital papilla may represent a transitory condition in species of Tatia, and perhaps is observed in specimens only close to reproductive phase. The elongated upper caudal-fin lobe in both mature females and males is rare within the genus and may be also associated to the reproductive phase. Tatia nigra occurs in sympatry with T. brunnea in the Trombetas river, at lago do Batata, but not syntopically. The specimens of T. nigra were captured in the lake, while the T. brunnea was recorded from the igarapé Saracazinho, a tributary of the Batata lake. Tatia strigata Soares-Porto, 1995 Figs. 40-42 Tatia cf. brunnea. Burgess, 1989: 242, pl. 113. [tropical South America]. Tatia strigata Soares-Porto, 1995: 202, fig. 1. [type locality: igarapé Limãozinho, Maués, Amazonas, Brazil]. Burgess & Finley, 1996:166 [reference]. Soares-Porto, 1998: 333 [citation]. Ferraris, 2003:477 [checklist]. Lasso et al., 2005: 139 [Alto Orinoco, Orinoco]. Ferraris, 2007: 78 [checklist]. Diagnosis. Tatia strigata is the only species of the genus with a completely striped color pattern, bearing whitish elongate longitudinal irregular stripes along lateral sides of body. A unique arrangement of adult male modified anal fin is present, with the second unbranched anal-fin ray with anterior enlarged segments and a notch formed by the reduction of the second and third branched rays (Soares-Porto, 1995). Tatia strigata is also distinguished from all congeners by a combination of characteristics: four branched pectoral-fin rays; 7 ribs; 29-30 vertebrae; and mature males with upper caudal-fin lobe slightly elongated, same length in females. Fig. 36. Tatia nigra. (a) holotype, INPA 12291, male, 116.8 mm SL. (b) paratype, INPA 25501, female, 107.3 mm SL, Uatumã river, Amazonas State, Brazil. L. M. Sarmento-Soares & R. F. Martins-Pinheiro 535 Description. Measured specimens 36.5-55.0 mm SL; morphometric data presented in Table 13. Body slim, head slightly depressed dorso-ventrally. Head large, robust, outline of head in dorsal view somewhat elliptic, broader than long. Trunk from dorsal-fin base to caudal peduncle gradually compressed. Lateral profile of head from snout tip to opercular margin slightly convex until pectoral-fin insertion. Ventral profile of head and abdomen flat. Ventral profile of body gently curved, concave behind anal-fin origin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended postero-laterally as well-developed fleshy rictal fold; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils larger than distance between posterior ones. Maxillary barbel short, extending close to posterior tip of postcleithral process, sometimes shorter; mental barbel short, tips not reaching pectoralfin base, arranged in arc along ventral surface of jaw; inner mental barbel about 50.0-60.0% length of outer mentals. Postcleithral process almost reaching vertical through origin of dorsal fin. Caudal peduncle deep, depth about 13.6-14.5% SL. Rostral border of cranium with mesethmoid as large as long; premaxilla underneath with synchondral articulation; large elliptical cranial fontanel bounded by mesethmoid and frontal (Fig. 41); nasal ossified with medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla about the same size as autopalatine; prevomer expanded anteriorly with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with three rows of conical teeth. First nuchal plate somewhat pentagonal; second nuchal plate concave along lateral margins; third nuchal plate curved, projected laterally. Epioccipital process very small. Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as short canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last one flattened. Four infraorbital bones in incomplete series. Infraorbital 1 broad, with short ventro-lateral process; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and by two posterior canal bones much close to sphenotic, forming posterior orbital rim. Lateral line on body with ossified canal bones limited to head. Dorsal fin I,4-5 (n=10); dorsal-fin spine with 15-20 antrorse Table 12. Morphometric data for Tatia nigra. SD = standard deviation. Holotype Range Mean SD N INPA 12291 Standard length 116.8 70.0-116.8 101.6 12 Percents of standard length Body depth 19.9 17.0-21.9 19.5 1.47 12 Body width 18.7 18.7-21.6 19.6 0.81 12 Caudal peduncle depth 15.4 14.4-17.0 15.8 0.77 12 Caudal peduncle length 28.6 22.2-28.6 26.4 1.99 12 Predorsal length 30.1 27.4-31.0 29.9 0.94 12 Preanal length 68.6 64.0-75.4 68.1 3.30 12 Prepelvic length 47.5 47.3-51.9 49.5 1.47 12 Dorsal origin to pectoral origin 21.0 18.5-23.3 21.0 1.36 12 Dorsal origin to pelvic origin 27.4 27.2-32.4 29.9 1.83 12 Pectoral origin to pelvic origin 33.1 30.7-37.3 32.7 1.75 12 Prepectoral length 17.8 17.8-22.1 19.4 1.26 12 Dorsal-fin base length 11.1 8.6-11.4 9.9 0.80 12 Adipose-fin base length 10.4 10.3-12.5 11.0 0.68 12 Anal-fin base length 4.2 3.0-11.9 7.9 3.50 12 Dorsal-fin spine length 19.7 16.3-22.0 19.7 1.54 9 Pectoral-fin spine length 20.5 20.3-24.6 22.7 1.42 9 Postcleithral process lenght 12.3 12.0-14.4 13.1 0.81 12 First branched pelvic-fin ray 13.8 11.8-15.1 13.6 1.19 12 Longest anal fin ray 8.3 4.7-10.7 8.8 1.83 12 Maxillary barbel length 27.9 25.6-30.9 27.8 1.91 12 Outer mental barbel length 8.4 6.5-10.1 8.1 1.09 12 Mental barbel length 4.3 3.6-5.8 4.8 0.65 12 Head length 19.2 19.2-22.9 21.3 1.08 12 Percents of head length Head width 82.1 77.5-82.2 80.0 1.97 12 Snout depth 49.1 47.0-53.7 48.8 1.99 12 Interorbital distance 66.5 61.3-66.7 63.5 1.99 12 Left internarial width 26.3 22.4-26.5 24.7 1.53 12 Anterior internarial distance 44.6 39.8-44.6 42.7 1.98 12 Posterior internarial distance 42.4 34.6-42.4 39.0 1.91 12 Snout length 40.6 38.5-43.1 40.6 1.95 12 Orbital diameter 24.1 23.0-27.8 25.8 1.92 12 Mouth width 53.6 48.5-53.6 51.2 1.96 12 Fig. 37. Neurocranium of Tatia nigra, MNRJ 32024, 97.0 mm SL. Dorsal view. Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm. A systematic revision of Tatia 542 system in two species of internally inseminating south american catfishes, Trachelyopterus lucenai and T. galeatus (Teleostei: Auchenipteridae). Journal of Morphology, 246: 131-141. Ministério do Meio Ambiente. 2004. Lista Nacional das Espécies de Invertebrados Aquáticos e Peixes Ameaçadas de Extinção. Instrução Norminativa 5, Anexo I. Pp. 136-141. In: Diário Oficial da União, seção 1, no. 102, sexta-feira, 28 de maio de 2004. Imprensa Nacional. Miranda Ribeiro, A. 1911. Fauna brasiliense. Peixes. Tomo IV (A) [Eleutherobranchios Aspirophoros]. Arquivos do Museu Nacional do Rio de Janeiro, 16: 1-504. Miranda Ribeiro, A. 1918. Três gêneros e dezessete espécies novas de peixes Brasileiros. Revista do Museu Paulista, 10: 631-646. Miranda Ribeiro, P. 1962. Catálogo dos peixes do Museu Nacional, IX. Publicações Avulsas do Museu Nacional, Rio de Janeiro, 45: 1-12. Miranda Ribeiro, P. 1968. Apontamentos ictiológicos IV. Boletim do Museu Nacional, Rio de Janeiro, Nova Série, Zoologia, 262: 1-7. Nakatani, K., A. A. Agostinho, G. Baumgartner, A. Bialetzki, P. V. Sanches, M. C. Makrakis & C. S. Pavanelli. 2001. Ovos e larvas de peixes de água doce: desenvolvimento e manual de identificação. Maringá: EDUEM, 378p. Ortega, H. & R. P. Vari. 1986. Annotated checklist of the freshwater fishes of Peru. Smithsonian Contributions to Zoology, 437: 125. Pearson, N. E. 1937. The fishes of the Atlantic and Pacific slopes near Cajamarca, Peru. Proceedings of the California Academy of Sciences, 23: 87-98. Pellegrin, J. 1899. Notes les poissons recueillis par M.F. Geay dans l´Apuré et sés affluents. Bulletin Musée de Histoire Naturelle de Paris 5: 156-159. Puyo, J. 1949. Poissons de la Guyane française. Faune de l’empire Français. ORSOM, Paris, 12, 280 p. Rössel, F. 1962. Centromochlus schultzi, ein neues wels aus Brasilien (Pisces, Teleostei, Auchenipteridae). Senckenbergiana Biologica, 43: 27-30. Royero, R. 1992. Tatia musaica, una nueva especie de bagre auquenipterido (Siluriformes -Auchenipteridae) de la cuenca del Rio Orinoco, Territorio Federal Amazonas, Venezuela. Acta Cientifica Venezuelica, 43: 300-306. Sands, D. 1984. Catfishes of the World. Catfishes of the world, 3, Suppl (first set): 58:1-8. Sarmento-Soares, L. M. & M. Porto. 2006. Comparative anatomy of the cheek muscles within the Centromochlinae subfamily (Ostariophysi, Siluriformes, Auchenipteridae). Journal of Morphology, 267: 187-197. Schultz, L. P. 1944. The catfishes of Venezuela, with descriptions of thirty-eight new forms. Proceedings of the United States National Museum, 94: 173-338. Soares-Porto, L. M. 1995. A new species of Tatia from the Amazon basin (Siluriformes: Auchenipteridae). Ichthyological Exploration of Freshwaters, 6: 201-206. Soares-Porto, L. M. 1996. Análise filogenética dos Centromochlidae. Redefinição e revisão taxonômica de Tatia A. de Miranda Ribeiro, 1911 (Osteichthyes, Siluriformes, Doradoidea). Unpublished Doctoral Dissertation. Universidade de São Paulo, São paulo. 278 p. Soares-Porto, L. M. 1998. Monophyly and interrelationships of the Centromochlinae (Siluriformes, Auchenipteridae), p. 331350, In: L. R. Malabarba, R. E. Reis, R. P. Vari, Z. M. S. Lucena & C. A. S. Lucena (eds.). Phylogeny and Classification of Neotropical fishes.Edipucrs, Porto Alegre, 603p. Steindachner, F. 1876. Die süsswasserfische des südöstlichen Brasilien. Sitzungsberichte der Akademie der Wissenschaften in Wien, Mathematisch-Naturwissenschaftlichen, 74: 559-694. Steindachner, F. 1882. Beiträge zur kenntnis der flussfische Südamerika´s, III. Denkschriften der Kaiserlinchen Akademie der Wissenschaften in Wien, MathematischNaturwissenschaftliche, 44: 1-18. Taylor, W. R. & G. C. Van Dyke. 1985. Revised procedures for staining and clearing small fishes and other vertebrates for bone and cartilage study. Cybium, 9: 107-119. Vaillant, L. L. 1899. Note préliminaire sur les collections ichthyologiques recueillies par M. Geay en 1897 et 1898 dans la Guyane française et le Contesté franco-brésilien. Bulletin du Muséum d’Histoire Naturelle, Paris, 5: 154-156. Vaillant, L. L. 1900. Contribution a l´étude de la faune ichthyologique de la Guyane Française et du Contesté franco-brésilien. Nouvelle Archives Musée de Histoire Naturelle de Paris, 2: 123-126. Verissimo, S., C. S. Pavanelli, H. A. Britski & M. M. Moreira. 2005. Fish Manso Reservoir region of influence, Rio Paraguay basin, Mato Grosso State, Brazil. Check List 1: 1-9. Wallace, A. R. 2002. Peixes do Rio Negro [Fishes of the Rio Negro]. Organization, introductory text and translation by Mônica de Toledo-Piza Ragazzo. Editora da Universidade de São Paulo, São Paulo, Brazil. 517p. ZFIN Project - The Zebrafish Information Network (ZFIN), University of Oregon, Eugene, OR 97403-5274; World Wide Web URL: http://zfin.org/zf_info/anatomy/dict/sum.html; [april, 3rd. 2008]. Accepted August, 2008 Published September 30, 2008