Taxonomic review of Hisonotus Eigenmann & Eigenmann (Siluriformes: Loricariidae: Hypoptopomatinae) from the laguna dos Patos system, southern Brazil

1 Neotropical Ichthyology, 9(1):1-48, 2011 Copyright © 2011 Sociedade Brasileira de Ictiologia Taxonomic review of Hisonotus Eigenmann & Eigenmann (Siluriformes: Loricariidae: Hypoptopomatinae) from the laguna dos Patos system, southern Brazil Tiago Pinto Carvalho1 and Roberto E. Reis2 The species of Hisonotus from the laguna dos Patos system are reviewed. Two species with wide distributions are redescribed: Hisonotus laevior and H. nigricauda. Six new species are described from that system: H. notopagos from the rio Camaquã drainage; H. carreiro and H. prata, endemic from the headwaters of rio Taquari drainage; H. vireo, widely distributed in the rio Jacuí basin; and H. brunneus and H. heterogaster restricted to tributaries of the rio Jacuí drainage. Hisonotus leptochilus is here considered a junior synonym of H. laevior. Hisonotus armatus, H. charrua, H. leucofrenatus, and H. taimensis are also present in the region and in total there are twelve species of Hisonotus in the laguna dos Patos system. Their distributions are discussed, species are illustrated and a taxonomic key is provided. As espécies de Hisonotus do sistema da laguna dos Patos são revisadas. Duas espécies com amplas distribuições são redescritas: Hisonotus laevior e H. nigricauda. Seis espécies novas são descritas deste sistema: Hisonotus notopagos, da drenagem do rio Camaquã; H. prata e H. carreiro, endêmicas das cabeceiras do rio Taquari; H. vireo, amplamente distribuída na bacia do rio Jacuí; H. brunneus e H. heterogaster dos tributários da bacia do rio Jacuí. Hisonotus leptochilus é considerado sinônimo júnior de H. laevior. Hisonotus armatus, H. charrua, H. leucofrenatus e H. taimensis também são encontradas na região, e ao total doze espécies de Hisonotus estão presentes no sistema da laguna dos Patos sendo suas distribuições discutidas aqui. As espécies são ilustradas e uma chave taxonômica é fornecida. Key words: Cascudinhos, Endemism, Geographic variation, Neotropical. 1University of Louisiana at Lafayette, Department of Biology, P. O. Box 42451, Lafayette, LA 70504, USA. [email protected].br 2Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul. P. O. Box 1429, 90619-900 Porto Alegre, RS, Brazil. [email protected] Introduction Hisonotus is part of the Hypoptopomatinae, a group of small loricariids including more than 100 species grouped in 19 genera (Schaefer, 2003; Reis & Carvalho, 2007; Carvalho et al., 2008), distributed in the cis-Andean drainages from Venezuela to northern Argentina. Hisonotus was described by Eigenmann & Eigenmann (1889) based on the following diagnostic characters: belly with large plates, eyes superior, and humeral plate imperforate. The type species, Hisonotus notatus, was collected at Santa Cruz, within urban area of Rio de Janeiro. Regan (1904) conducted the first revision of loricariids, and placed Hisonotus, Parotocinclus Eigenmann & Eigenmann, 1889 and Microlepidogaster Eigenmann & Eigenmann, 1889 under the synonymy of Otocinclus Cope, 1871. Hisonotus was resurrected by Schaefer (1998), being diagnosed by reduced or absent snout plates anterior to the nostril, rostrum with enlarged odontodes, and plates forming the lateral rostral margin thickened (Schaefer, 1998: 387). Those diagnostic features were discussed by Britski & Garavello (2007: 6), being considered variable among species of Hisonotus. The position of Hisonotus within Hypoptopomatinae diverges to some degree in the phylogenetic analyses of the subfamily using morphological data (Schaefer, 1998; Gauger & Buckup, 2005). In the first analysis (Schaefer, 1998), Hisonotus appears relatively basal within the Otothyrini, more derived than Parotocinclus and “New Taxon 3”. In the hypothesis proposed by Gauger & Buckup (2005), the monophyletic status of Otothyrini is not corroborated, and Hisonotus is the sister group to Parotocinclus. More recently, molecular hypothesis supported the polyphyly of Hisonotus (Cramer et al., 2007; Taxonomic review of Hisonotus from the laguna dos Patos system 2 Chiachio et al., 2008), species of the genus appearing in at least three different clades. Unfortunately none of these molecular hypotheses included the type species (Hisonotus notatus), which is mandatory for future taxonomic changes and new rearrangements. The first Hypoptopomatinae described for the laguna dos Patos system was Otocinclus nigricauda. It was described by Boulenger (1891) based on the material collected by Dr. Hermann von Ihering and Herr Sebastian Wolff in the Province (presently State) of Rio Grande do Sul, which had been sent to the British Museum of Natural History. This species was transferred to Hisonotus by Cope (1894) based on the examination of a fish collection from the Rio Jacuhy (rio Jacuí) made by Mr. Herbert Smith. In that work, Cope described several new species including Hisonotus laevior and H. leptochilus, and presented diagnostic comparisons between the four species pertaining to the genus, at that time. After a long period, another species of Hisonotus was described from the laguna dos Patos system, Microlepidogaster taimensis Buckup, 1981 from the marshes of the Taim region. In the last published list of species of laguna dos Patos system (Malabarba, 1989), four species of Hisonotus (that time still Microlepidogaster) were considered valid in this region (H. nigricauda, H. laevior, H. leptochilus, and H. taimensis). Nowadays, Hisonotus consists of 22 nominal species (Schaefer, 2003; Azpelicueta et al., 2007; Britski & Garavello, 2007; Carvalho & Reis, 2009), occurring in the Atlantic coastal drainages of southern and southeastern Brazil, río de La Plata system, laguna dos Patos system, and recently extended to the Amazon basin in the rio Tapajós drainage (Britski & Garavello, 2007). Buckup (1981: 19) had already mentioned that the difficulties in the study of hypoptopomatines from southern Brazil were in part due to the limitation of the species description and the lack of recent reviews. The objective of this paper is to describe the diversity of Hisonotus in the laguna dos Patos system, in southern Brazil. In this work we are redescribing Hisonotus nigricauda and H. laevior (senior synonym of H. leptochilus), and describing six new species, with an identification key for Hisonotus in this hydrographic system. Although some species in this study do not have some of the features used by Schaefer (1998: 387) to diagnose Hisonotus, they do share apomorphic features with species that can be unambiguously diagnosed as belonging to Hisonotus. Material and Methods The studied area is the laguna dos Patos system, an area located in the southeast portion of the Brazilian State of Rio Grande do Sul and a minor portion in northeastern Uruguay. It is one of the Freshwater Ecoregions of the World (FEOW; Abell et al., 2008). The main water bodies that compose the system are the laguna dos Patos (9,280 km2), the laguna Mirim (3,520 km2), and its main tributaries rio Jaguarão, rio Camaquã, and rio Jacuí (Schwarzbold & Schäfer, 1984) (Fig. 1). The entire hydrographical system is connected to the Atlantic Ocean by the channel of Rio Grande. The system is limited by the tributaries of rio Uruguay and rio Pelotas in the north; tributaries of rio Ijuí in the northwest; tributaries of rio Ibicuí in the west; and the rio Negro watershed in the southwest, all part of the rio Uruguay basin. In the eastern portion, the system is limited by the coastal plain, a narrow sandy band (5 to 30 km wide) parallel to the coast line, which has a great number of shallow lakes and lagoons, bordering the rio Tramandaí system in its northeastern limit (Malabarba, 1989). The major tributary river to the laguna dos Patos system is the rio Jacuí, which flows into the lago Guaíba in the northern portion of the laguna dos Patos. The Jacuí basin is formed by several tributaries, including the drainages of rio dos Sinos, rio Caí, and rio Taquari (Fig. 1). Measurements were made to the nearest 0.1 mm with digital calipers under a stereomicroscope on the left side of specimens. The measurements and their abbreviations follow Carvalho & Reis (2009: 3, fig. 1). Morphometric data are expressed as percents of standard length (SL), except for subunits of the cephalic region that are expressed as percents of head length (HL). Plate counts and nomenclature follow the schemes of serial homology proposed by Schaefer (1997). Vertebral counts include all vertebrae (including the first five vertebrae incorporated into the Weberian apparatus), with the compound caudal centrum (PU1+U1) counted as one element. Accessory patch of teeth is that described by Reis & Schaefer (1992). Cleared and stained specimens (c&s) were prepared according to the method of Taylor & van Dyke (1985). Whenever available, juvenile specimens were also cleared and stained. The term juvenile was used for specimens not totally covered by plates, with an anterior paired crest of odontodes on the parieto-supraoccipital, and also for males without a fleshy flap on the first thickened pelvic-fin ray. Scanning electron microscope pictures were taken from dissected alcohol preserved specimens. Drawings were prepared from c&s specimens using a Zeiss SV8 stereomicroscope with camera lucida attachment. Institutional abbreviations are as follows: Asociación Ictiológica, La Plata (AI); Academy of Natural Sciences of Philadelphia (ANSP); Natural History Museum, London (BMNH); Instituto de Limnología “Dr. Raúl A. Ringuelet”, La Plata (ILPLA); Instituto Nacional de Pesquisas da Amazônia, Manaus (INPA), Museo Argentino de Ciências Naturales Bernadino Rivadavia, Buenos Aires, (MACN); Museu Anchieta, Porto Alegre (MAPA); Fundação Zoobotânica do Rio Grande do Sul/ Museu de Ciências Naturais, Porto Alegre (MCN); Museu de Ciências da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre (MCP); Museo de La Plata, La Plata (MLP); Museu Nacional, Rio de Janeiro (MNRJ); Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Maringá (NUP); Universidade Federal do Rio Grande do Sul, Porto Alegre (UFRGS); Faculdade de Ciências Universidad de La República, Montevideo (ZVC-P). In this paper we are redescribing all the species of Hisonotus originally described from this system, with the T. P. Carvalho & R. E. Reis 3 exception of Hisonotus armatus and Hisonotus taimensis, which have modern and complete descriptions. Hisonotus charrua and Hisonotus leucofrenatus were not redescribed in this paper because were not originally described from the laguna dos Patos system. The first has a recent and complete description (Almirón et al., 2006), and the second needs a complete review thoroughout it distribution and a neotype designation, which is beyond the scope of this paper. Principal Component Analysis (PCA) was used to check overall variation among samples including differences in morphometrics among species, being an input to multiple regressions. Analyses were made using all measurements listed above except for the pelvic-fin unbranched ray length (VL), which is strongly correlated with sexual dimorphism. Fin-spine measurements were removed whenever presenting missing entries. PCA on covariances of base 10 logarithmically transformed measurements were obtained using Past version 1.28 2004 (Ryan et al., 1995). The first principal component was partioned out, considering that it mostly accounts for size variation (Strauss, 1985). Factor scores were plotted with Sigma Plot version 6.10 2000 (Brannan et al., 2000). Multiple linear regressions were applied to describe morphometric differences among species or individuals of the same species. Results Hisonotus nigricauda (Boulenger, 1891) Figs. 2, 3, 4a, 5, 6a, 7a, and 8a Otocinclus nigricauda Boulenger, 1891: 234 [original description, type locality: Rio Grande do Sul, Brazil]. -Regan, 1904: 268-269 [redescription, senior synonym of Hisonotus laevior and Hisonotus leptochilus]. Fowler, 1940: 83 [listed]. -Isbrücker, 1980: 84 [listed]. -Schaefer, 1991: 23 [phylogenetic relationships of Hypoptopomatinae]. Hisonotus nigricauda Cope, 1894: 97 [compared with Hisonotus laevior and H. leptochilus and new generic combination]. -Schaefer, 1998: 383 [transferred to Hisonotus]. -Schaefer, 2003: 232 [listed]. -Reis & Carvalho, 2007: 84 [listed]. -Ferraris, 2007: 248 [listed]. Fig. 1. Drainage map of laguna dos Patos system (dashed area) and the neighboring rio Uruguay basin and coastal drainages of south Brazil. Rectangle represents the rio Jacuí basin (detailed in Fig. 32). 1 - mouth of rio Vacacaí drainage; 2 - mouth of rio Caí drainage; 3 - mouth of rio dos Sinos drainage; 4 - lago Guaíba; 5 - rio São Gonçalo drainage. Taxonomic review of Hisonotus from the laguna dos Patos system 4 Microlepidogaster nigricauda. -Eigenmann, 1910: 413 [listed]. Miranda Ribeiro, 1911: 88 [listed]. Fowler, 1915: 237 [examined specimen]. -Gosline, 1945: 101 [listed]. -Fowler, 1954: 166-167 [listed and illustrated]. -Malabarba, 1989: 150 [type locality restricted to laguna dos Patos system, probably rio Camaquã]. -Schaefer, 1997: 8 [listed]. Diagnosis. Hisonotus nigricauda differs from its congeners, except from H. maculipinnis and H. prata, by lacking the posterior portion of the lateral line (Fig. 4a), vs. posterior portion of lateral line present. It differs from H. maculipinnis and H. prata by having an almost completely dark caudal fin, without hyaline areas in the middle portion (Figs. 2-3), vs. caudal fin presenting hyaline areas in the middle portion (see remarks for H. maculipinnis diagnosis). Description. Morphometrics and meristics in Table 1. Adult size small to medium for members of this genus (less than 40 mm in SL). Body robust, not elongated. Head and body without conspicuous keels. Caudal peduncle round in cross section. Dorsal profile slightly convex from snout tip to dorsalfin origin except slightly concave profile anterior to nares. Straight and posteroventrally sloped at dorsal-fin base, and almost straight from that point to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at posterior end of caudal peduncle. Posterior profile of caudal-fin margin slightly concave. Head and snout broad, snout rounded to somewhat square in dorsal view, body progressively narrowing posterior to pectoral-fin insertion. Snout region anterior to nares concave, interorbital region slightly convex. Upper margin of orbit somewhat elevate. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6. Pectoral-fin posterior margin almost straight; when depressed tip extending to middle of pelvic fin. Posterior margin of pectoral-fin spine smooth in adults and juveniles. Pectoral-fin axillary slit present, located below Fig. 2. Hisonotus nigricauda, BMNH 91.3.16.53-62, syntype of Otocinclus nigricauda, female, 29.9 mm SL. Laguna dos Patos system, Rio Grande do Sul, Brazil. T. P. Carvalho & R. E. Reis 5 posterior bony margin of cleithral process. Pelvic fin i,5. Tip of depressed pelvic fin not reaching anal-fin origin in females, but extending beyond that point in males. Dorsal fin II,7. Dorsal-fin origin located just posterior of vertical through pelvic-fin origin. Dorsal-fin spinelet somewhat round in shape. Anal fin i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Body almost entirely covered by plates except for region overlying opening of swim bladder capsule, area between pectoral girdle and lower lip, region around anus, and area around base of paired fins. Rostral plate with posterior notch articulation for mesethmoid. Rostral plate thickened, with narrow odontode free band between dorsad and ventrad series of odontodes (Fig. 5), odontode-free area sometimes absent in smaller specimens. Snout plates anterior to nares reduced, small unplated area between rostrum and nares (Fig. 6a). Two or three rows of predorsal plates (modally three; Fig. 7a). Lateral line incomplete, anterior portion short, formed by one to three pored plates. Posterior portion of lateral line absent. Median plate series usually truncated (Fig. 4a). Plates of median abdominal plate series very small, numerous, irregularly arranged. Lateral abdominal plates larger, forming regular series of about four to seven plates on each side (Fig. 8a). Coracoid and cleithrum exposed and covered by odontodes, except for median region of cleithrum between arrector fossae openings and medial region of coracoids. Fig. 3. Hisonotus nigricauda, MCP 40761, female, 37.2 mm SL. Arroio Banhado Grande on road between Bagé and Caçapava do Sul, Bagé, Brazil. Taxonomic review of Hisonotus from the laguna dos Patos system 6 Head, fin-spines, and body plates covered with odontodes, these larger on anterior surface of all fin spines, medially directed on pelvic fin. Odontodes on head uniform in size and distribution, except for enlarged odontodes on ventral and dorsal margins of rostrum (Fig. 5). Odontodes on posterior parieto-supraoccipital tip not enlarged, about same size as surrounding areas. Anteroventral margin of compound pterotic with median-to-large size perforations. Infraorbital canal entering infraorbital series via sphenotic. Lips roundish and papillose. Maxillary barbel present. Premaxillary and dentary teeth slender proximally and flattened distally; bifid, major (medial) cusp large and rounded, minor (lateral) cusp pointed. Accessory patch of teeth absent on dentary and premaxilla. Compound ventral hypural plate (hypurals 1-2) and compound dorsal hypural plate (hypurals 3-5) not completely fused to each other, median notch on posterior margin of caudal-fin skeleton extending anteriorly. Total vertebrae 2728 (4 c&s), one c&s presenting 25 (apparently anomalous). Color in alcohol. Ground color of dorsal and lateral surfaces gray to almost black. Dorsal and dorsolateral body surfaces slightly lighter than lateral surface, except for head, which is Fig. 4. Lateral view of left side lateral plate series. a. Hisonotus nigricauda, MCP 40761, 37.4 mm SL. b. Hisonotus laevior, MCP 23854, 41.8 mm SL. c. Hisonotus notopagos, MCP 25924, 44.4 mm SL. d. Hisonotus carreiro, MCP 40945, 31.2 mm SL. e. Hisonotus prata, MCP 22204, 28.9 mm SL. f. Hisonotus vireo, MCP 14619, 41.3 mm SL. g. Hisonotus brunneus, MCP 22701, 40.1 mm SL. h. Hisonotus heterogaster, MCP 41073, 39.8 mm SL. Anterior portion toward left. Scale bars = 4 mm. Fig. 5. Scanning electron micrograph of anterior rostral margin of Hisonotus nigricauda, MCP 17416, 36.7 mm SL. a. Anterior view of rostrum; b. Magnification of medial portion. T. P. Carvalho & R. E. Reis 7 Fig. 6 (left column). Snout in dorsal view showing arrangement of snout plates. a. Hisonotus nigricauda, MCP 19548, 35.4 mm SL. b. Hisonotus taimensis, MCP 17417, 35.3 mm SL. c. Hisonotus notopagos, MCP 22294, 35.4 mm SL. RP - Rostral Plate, pr1 - first postrostral plate, io1 - first infraorbital, PN - prenasal plates, NA - Nasal, PSB - palatine seasamoidal bone, PF - prefrontal, F - frontal, LEE - exposed lateral ethmoid. Anterior portion toward left. Scale bar = 2 mm. Fig. 7. Predorsal region in dorsal view showing arrangement of predorsal plates. a. Hisonotus nigricauda, MCP 40761, 32.4 mm SL. b. Hisonotus laevior, MCP 23854, 38.7 mm SL. 1-3 - paired predorsal plates, 4 - nuchal plate, SOC - parietosupraoccipital. Anterior portion toward left. Scale bars = 2 mm. darker. Ventral surface of body heavily pigmented. Area anterior to nares lighter but not forming conspicuous longitudinal light stripes. Paired, dorsal and anal fins mostly hyaline, except for several transverse dark bands. Caudal fin almost completely dark, except for hyaline area on posterior portion of three uppermost branched rays. Caudal-fin hyaline portion, and the unbranched rays with transverse dark bands. Taxonomic review of Hisonotus from the laguna dos Patos system 8 Sexual dimorphism. Urogenital papilla positioned just behind the anal opening in males. Adult males also possess a developed fleshy flap along the dorsal margin of first thickened pelvic-fin ray, that is absent in females. Flap slightly wider basally and progressively narrowing distally. In adult males, the first and second branched rays of pelvic fin present a fleshy flap at its anteromedial portion. In juvenile males all flaps are smaller or absent. Males have a longer pelvic-fin unbranched ray that extends beyond the anal-fin origin, with the ray never reaching that point in females. Distribution and habitat. Hisonotus nigricauda is widely distributed in the laguna dos Patos system and in the rio Uruguay basin. In the laguna dos Patos system that species is found mostly in the lower portions of the tributaries near the laguna do Patos, being absent in the upper portions of rio Jacuí basin. In the same manner, H. nigricauda is most commonly collected in the lower portions of the rio Uruguay basin, but being found in the headwaters of rio Negro, rio Quaraí, and rio Ibicuí drainages (Fig. 9). Hisonotus nigricauda is apparently absent in the rio Uruguay basin above the mouth of rio Ibicuí. This species inhabits slow flowing watercourses, Fig. 8. Arrangement of abdominal plates. a. Hisonotus nigricauda, MCP 40761, 37.4 mm SL. b. Hisonotus laevior, MAPA 1755, 35.3 mm SL. c. Hisonotus notopagos, MCP 25924, 44.4 mm SL. d. Hisonotus carreiro, MCP 40954, 31.2 mm SL. e. Hisonotus prata, MCP 22204, 28.9 mm SL. f . Hisonotus vireo, MCP 14619, 41.3 mm SL. g. Hisonotus brunneus, MCP 22701, 40.1 mm SL. h. Hisonotus heterogaster, MCP 41073, 39.8 mm SL. Anterior portion toward top. Scale bars = 2 mm. Fig. 9. Drainage map of laguna dos Patos system and rio Uruguay basin showing distribution of Hisonotus nigricauda. Open symbol designate the probable type locality; some symbols represent more than one collecting locality. T. P. Carvalho & R. E. Reis 9 of brown waters running over dark organic matter and sandy bottom (Fig. 10c). The individuals were found in between marginal and aquatic vegetation. Remarks. Hisonotus nigricauda is morphologically very similar to Hisonotus maculipinnis (Regan, 1912) from río de La Plata in Argentina; both nominal species being morphometrically identical (Fig. 11). However, the following features can distinguish them: H. nigricauda has an almost completely dark caudal fin contrasting with a caudal fin with hyaline areas in most specimens of H. maculipinnis (including the type series), especially in juvenile specimens (Fig. 12). Specimens of H. nigricauda usually posses a narrow odontode-free area between dorsal and ventral series of odontodes on the anterior margin of snout, which is absent in H. maculipinnis specimens. These features putatively distinguish the forms, and both seem to be part of a species complex inhabiting the lower portions of the Paraná-Paraguay and laguna dos Patos systems. Further Fig. 10. a. Type locality of Hisonotus carreiro: rio Carreiro downstream of Carreiro bathing pool, Serafina Corrêa, Brazil. b. Type locality of Hisonotus prata: rio da Prata at Passo do Despraiado, Nova Prata, Brazil. c. Arroio Banhado Grande, slow flowing stream collecting site of Hisonotus nigricauda. d. Type locality of Hisonotus notopagos: small creek tributary to arroio das Lavras, Lavras do Sul, Brazil. study, however, is necessary to unambiguously demonstrate that these species are not conspecific, which is beyond the purposes of this work. Material examined. Brazil, Rio Grande do Sul, laguna dos Patos system: BMNH 91.3.16.53-62, syntypes of Otocinclus nigricauda, 9, 24.8-31.8 mm SL. Rio Jacuí drainage: ANSP 21565, 2, 21.322.4 mm SL, rio Jacuí. MCN 16246, 10, 23.7-34.1 mm SL, Porto Alegre, Parque Estadual Delta do Jacuí, Saco da Pólvora, 30º01’S 51º14’W. MCP 19834, 12, 25.6-40.2 mm SL, Amarópolis, creek tributary of rio Jacuí in the sylviculture Santo Amaro, 29º55’S 51º55’W. MCP 20543, 1, 31.1 mm SL, Porto Alegre, rio Jacuí on Saco da Alemoa, 30º00’00”S 51º14’51”W. Rio Caí drainage: MCN 15989, 3, 27.3-31.7 mm SL, Triunfo, mouth of rio Caí, left margin, 29º55’54”S 51º16’29”W. Rio Vacacaí drainage: MCP 19584, 33 + 3 c&s, 22.739.1 mm SL, São Gabriel, bridge on road between São Gabriel and Tiaraju, 30º17’29”S 54º20’18”W. MCP 26756, 5, 24.2-29.5 mm SL, São Gabriel, marsh of arroio Piraí, 30º17’07”S 54º20’33”W. Rio Gravataí drainage: MAPA 1737, 1, 26.7 mm SL, Gravataí, arroio Passo dos Ferreiros, tributary of rio Gravataí, 29º56’S 50º58’W. MAPA 1759, 3, 23.5-27.5 mm SL, Canoas, canal south of rio Gravataí. MCP Taxonomic review of Hisonotus from the laguna dos Patos system 16 Material examined. All from laguna dos Patos system, Rio Grande do Sul, Brazil. Rio Jacuí drainage: ANSP 21253, holotype of Hisonotus laevior, 39.2 mm SL, rio Jacuí. ANSP 21564, holotype of Hisonotus leptochilus, 40.9 mm SL, rio Jacuí. MCN 5823, 5, 14.8-30.7 mm SL, São Jerônimo, arroio da Porteira at fazenda Capão. MCP 9302, 2, 28.7-30.2 mm SL, Pantano Grande, arroio Dom Marcos, 30º13’32”S 52º37’09”W. MCP 9533, 3, 23.2-27.6 mm SL, Rio Pardo, arroio Francisquinho on highway BR-290 between Butiá and Rio Pardo, 30º09’S 52º08’W. MCP 19835, 12, 25.6-40.2 mm SL, Amarópolis, creek tributary of rio Jacuí in the sylviculture Santo Amaro, 29º55’S 51º55’W. MCP 27329, 2, 26.0-30.2 mm SL, Butiá, arroio Martins upstream of mine Recreio, 30º09’S 51º59’W. MCP 17359, 11, 18.931.4 mm SL, Arroio dos Ratos, arroio da Porteira, 29º24’S 51º57’W. UFRGS 2577, 2, 29.7-39.9 mm SL, Triunfo, arroio Gil on road between Barreto and Montenegro, 29º48’S 51º37’W. UFRGS 9153, 4, 33.843.2 mm SL, Candelária, riceculture canal near sanga das Oveiras, 29º48’00”S 52º36’58”W. Rio Vacacaí drainage: MCP 23131, 1, 33.5 mm SL, São Sepé, rio São Sepé at bridge lateral to highway BR-153, about 3 km south from São Sepé, 30º11’08”S 53º33’35”W. Rio Caí drainage: MAPA 1741, 17, 17.8-35.9 mm SL, São Sebastião do Caí, creek in Vila Conceição. MAPA 1744, 2, 26.836.0 mm SL, São Sebastião do Caí, arroio Três Mares. MAPA 1755, 24 + 3 c&s, 19.7-43.4 mm SL, São Sebastião do Caí, creek in rio Branco, 29º35’S 51º22’W. MCP 23005, 2, 14.6-39.6 mm SL, Triunfo, arroio Bom Fig. 18. Hisonotus laevior, ANSP 21564, holotype of Hisonotus leptochilus, female, 40.9 mm SL. Rio Jacuí, Brazil. T. P. Carvalho & R. E. Reis 17 Jardim, III Polo Petroquímico near SITEL, 29º50’19”S 51º23’25”W. MCP 26053, 1, 40.3 mm SL, Lindolfo Collor, arroio Feitoria tributary of rio Cadeia, 29º34’54”S 51º14’03”W. UFRGS 8661, 23, 31.6-43.0 mm SL, Butiá, creek on property Cerro Vermelho, 30º08’S 51º59’W. UFRGS 8720, 38, 30.4-46.1 mm SL, Rio Pardo, creek at fazenda Limoeiro, 29º59’S 52º22’W. UFRGS 8771, 8, 35.5-43.8 mm SL, Pantano Grande, creek on the border of fazenda Sanga Funda, 30º08’S 52º23’W. UFRGS 8777, 2, 36.4-48.1 mm SL, Rio Pardo, creek tributary of arroio Iruí at fazenda Limoeiro, 30º02’S 52º22’W. UFRGS 8786, 16, 28.8-43.6 mm SL, Pantano Grande, creek on the border of fazendas Tarumã I and Tarumã II, 30º08’S 52º23’W. Rio dos Sinos dranaige: MCN 18633, 1, 47.2 mm SL, Sapucaia do Sul, pesqueiro at Parque Zoológico of Sapucaia do Sul. Rio Gravataí drainage: MCN 6003, 1, 29.8 mm SL, Santo Antônio da Patrulha, arroio Chicoloma. MAPA 2626, 4, 32.9-38.0 mm SL, Gravataí, arroio Passo dos Ferreiros, 29º56’S 50º58’W. MAPA 2354, 1, 33.4 mm SL, Santo Antônio da Patrulha, arroio Ramos between Santo Antônio da Patrulha and highway BR-290. MAPA 2628, 2, 35.5-36.5 mm SL, Canoas, canal at south of rio Gravataí. MCN 6062, 1, 39.7 mm SL, Gravataí, Banhado Grande at fazenda Quatro Irmãos. MCP 14652, 5, 33.7-41.3 mm SL, Morungava, rio Morungava, 29º50’S 50º54’W. MCP 41574, 2, 36.2-40.8 mm SL, Gravataí, marsh at highway RS-118, BR-290, 29º58’S 50º56’W. Lago Guaíba drainage: MAPA 1734, 2, 28.5-27.5 mm SL, Guaíba, creek at fazenda Juncal km 39 of BR-290. MAPA 1848, 5, 32.5-43.8 mm SL, Porto Alegre, arroio Dilúvio between PUCRS and UFRGS câmpus. MCN 14795, 1, 39.1 mm SL, Mariana Pimentel, arroio Ribeiro Pequeno on road RS-711, 29º23’53”S 50º44’37”W. MCN 17567, 2, 32.3-33.8 mm SL, Porto Alegre, arroio Lami on road of Quirinas. MCP 16034, 12, 20.6-31.4 mm SL, Viamão, lago Guaíba at praia de Itapuã near to mouth of riacho Itapuã, 30º15’00”S 51º02’20”W. MCP 23466, 1, 40.9 mm SL, Viamão, arroio at praia da Pedreira, Parque Estadual de Itapuã, 30º21’30”S 51º02’48”W. MCP 28116 27.1-42.8 mm SL, Viamão, arroio Sandu, 30º14’S 51º00’W. MNRJ 25597, 1, 31.5 mm SL, Barra do Ribeiro, creek on road between Barra do Ribeiro and Guaíba about 8 km from Barra do Ribeiro. UFRGS 1239, 1, 38.1 mm SL, Viamão, arroio Alexandrina. UFRGS 2346, 7, 19.2-37.8 mm SL, Eldorado do Sul, lago Guaíba at Vila Sans Soucy. Laguna dos Patos drainage: MAPA 1753, 7, 24.1-42.3 mm SL, Tapes, arroio Teixeira on BR-116. MAPA 1757, 2, 28.5-33.3 mm SL, Palmares do Sul, canal 16 km north of sanga Pangaré on road between Capivari and Mostardas. MCN 2622, 1, 44.4 mm SL, Rio Grande, arroio Vieira, 32º06’S 52º09’W. MCN 12682, 7, 32.0-46.7 mm SL, São Lourenço do Sul, arroio Inhuquipá (Turuçu) near Formosa, 31º28’S 52º05’W. MCN 17632, 3, 18.5-40.0 mm SL, Palmares do Sul, channel of lagoa dos Gateados at fazenda São Sebastião do Fundo, 30º27’S 50º39’W. MCN 17549, 1, 38.7 mm SL, Palmares do Sul, channel of lagoa dos Gateados at fazenda São Sebastião do Fundo, 30º27’S 50º39’W. MCN 18138, 2, 32.5-32.6 mm SL, Palmares do Sul, south margin of lagoa do Casamento, 30º29’S 50º36’W. MCP 16016, 6, 14.7-34.8 mm SL, Viamão, creek on Varzinha at Itapuã, 30º19’S 50º56’W. MCP 19068, 1, 34.2 mm SL, Rio Grande, arroio Bolacha, 32º09’S 52º11’W. MCP 21375, 6, 25.6-40.5 mm SL, São José do Norte, laguna dos Patos at Barra Falsa upstream dam, 31º34’19”S 51º27’35”W. MCP 23856, 10, 31.6-43.8 mm SL, Sentinela do Sul, arroio Faxinal tributary of arroio Velhaco on road from Cerro Grande do Sul to Camaquã, 30º43’48”S 51º45’24”W. MCP 23859, 2, 27.1-41.8 mm SL, Sentinela do Sul, arroio Capivaras on road between Sentinela do Sul and Vila Aurora. 30º39’27”S 51º36’12”W. MCP 23860, 23, 27.6-46.2 mm SL, Tapes, arroio Texeira on highway BR-116, 30º37’26”S 51º32’45”W. MCP 31157, 4, 31.7-33.2 mm SL, Rio Grande, Saco da Mangueira, 32º05’S 52º09’W. MCP 41575, 23, 25.1-42.7 mm SL, Sentinela do Sul, arroio do Tigre tributary of arroio Velhaco on road from Cerro Grande do Sul to Camaquã, 30º44’30”S 51º46’26”W. MCP 41576, 2, 31.4-31.9 mm SL, Sentinela do Sul, arroio Velhaco on road from Cerro Grande do Sul to Camaquã, 30º41’22”S 51º41’51”W. UFRGS 4220, 3, 22.2-35.9 mm SL, Tapes, arroio Velhaco between Tapes and Camaquã, about 24 km from mouth in laguna dos Patos, 30º45’S 51º38’W. UFRGS 6698, 10, 13.8-38.3 mm SL, Viamão, lagoa Negra, 30º21’35”S 50º58’34”W. Rio Camaquã drainage: MCP 23854, 12, Fig. 19. Interorbital width as a function of head length of Hisonotus laevior. Open circle is holotype of H. laevior and triangle is holotype of H. leptochilus (R2 = 0.9291, P< 0.001). Table 3. Morphometrics and meristics of Hisonotus laevior. SD = Standard deviation, H = holotype of H. laevior, and h = holotype of H. leptochilus. Types Non-types H h n Low High Mean SD Standard length (mm) 39.2 40.9 65 29.3 47.2 38.0 - Percents of Standard length Head length 34.1 34.6 65 30.6 36.9 33.6 1.39 Predorsal length 45.1 48.2 65 43.2 49.8 46.4 1.34 Dorsal-fin spine length - 19.6 65 20.6 26.6 23.4 1.33 Anal-fin unbranched ray length 14.3 - 64 14.1 20.0 17.2 1.27 Pectoral-fin spine length 23.5 22.4 65 20.5 26.2 23.5 1.34 Pelvic-fin unbranched ray length 15.2 0.0 65 13.1 20.1 16.5 1.84 Cleithral width 22.2 22.2 65 20.6 24.6 22.9 0.85 Thoracic length 15.2 15.7 65 15.1 20.3 17.3 0.95 Abdominal length 19.9 19.4 65 18.0 21.9 19.9 0.79 Body depth at dorsal-fin origin 16.6 18.0 65 16.2 20.8 18.1 1.03 Caudal-peduncle length 33.2 33.8 65 31.0 37.0 33.7 1.31 Caudal-peduncle depth 11.1 11.1 65 9.2 12.5 10.8 0.68 Percents of Head length Snout Length 50.0 47.8 65 44.7 52.5 48.6 1.32 Orbital diameter 14.2 16.2 65 14.8 19.0 16.6 0.89 Interorbital width 41.6 39.5 65 36.9 46.2 41.9 1.95 Head depth 44.9 48.1 65 42.8 53.4 48.1 2.20 Suborbital depth 18.3 17.7 65 15.9 21.8 18.6 1.05 Mandibular ramus 7.6 8.2 65 7.0 11.1 8.8 0.86 Meristics Left premaxillary teeth 19 - 63 14 23 18.1 2.27 Right premaxillary teeth 17 17 62 14 23 18.1 2.12 Left dentary teeth - - 64 12 21 16.0 1.80 Right dentary teeth 15 15 64 11 20 16.1 2.07 Left lateral plates 26 26 65 25 27 25.6 0.65 Right lateral plates 26 26 65 25 27 25.6 0.62 Taxonomic review of Hisonotus from the laguna dos Patos system 18 34.8-44.7 mm SL, Cristal, creek tributary to arroio Santa Isabel on highway BR-116, about 17 km south from Cristal, 30º08’55”S 52º01’50”W. MCP 23857, 21, 27.8-38.9 mm SL, Camaquã, arroio Duro on road between Vila Aurora and Dom Feliciano, 30º45’34”S 51º51’57”W. MCP 25754, 4, 25.0-37.2 mm SL, Camaquã, arroio Maria Ulghim on road between Camaquã and Vila Aurora, 30º49’S 50º49’W. MCP 26042, 1, 42.3 mm SL, Caçapava do Sul, arroio do Banhado highway BR-153 about 8 km northwest from Minas do Camaquã, 30º51’48”S 53º29’50”W. MCP 41607, 1, 36.7 mm SL, Caçapava do Sul, small creek tributary to arroio Hilário on road between Caçapava do Sul and Lavras do Sul, 30º44’24”S 53º44’51”W. UFRGS 8239, 4, 32.5-41.3 mm SL, Canguçu, creek tributary to rio Camaquã on highway RS-471, 31º23’S 52º40’W. UFRGS 8758, 13, 23.9-40.5 mm SL, Amaral Ferrador, creek at fazenda Ferraria, 30º52’S 52º15’W. MCP 44501, 2, 26.0-32.1, Pinheiro Machado, creek tributary to arroio Boici at fazenda Chimarrão, 31º13’44”S 53º22’18”W. Rio São Gonçalo drainage: MCP 20821, 6, 37.8-39.4 mm SL, Pedro Osório, arroio Reduzino, 31º54’S 52º55’W. MCP 21424, 13, 33.4-48.9 mm SL, Herval, small creek tributary to arroio Arambaré, between Pedro Osório and Airosa Galvão, 31º58’19”S 53º05’39”W. MCP 21144, 4, 31.5-37.3 mm SL, Piratini, arroio Piratinizinho on vicinal road to highway BR-293, 31º43’02”S 52º59’34”W. MCP 25153, 19, 33.1-46.3 mm SL, Pedro Osório, arroio Arambaré on road between Pedro Osório and Basílio, tributary of rio Piratini, 31º54’35”S 53º01’40”W. MCP 34778, 1, 37.6 mm SL, Herval, arroio Arambaré on road between Pedro Osório and Herval, 31º58’37”S 53º06’15”W. MCP 34779, 8, 33.3-48.8 mm SL, Pedro Osório, arroio Mata Olho on road between Pedro Osório and Basílio, 31º54’56”S 53º00’16”W. MCP 37683, 4, 31.7-41.7 mm SL, Pedro Osório, creek tributary to arroio Arambaré near Carvalho de Freitas, about 35 km from Pedro Osório on the railroad bridge, 31º57’52”S 53º06’17”W. Laguna Mirim drainage. MCP 26074, 2, 38.9-41.22 mm SL, Rio Grande, canal do arroio Taim, Estação Ecológica do Taim, 32º37’S 52º34’W. Hisonotus leucofrenatus (Miranda Ribeiro, 1908) Figs. 20a and 21a Otocinclus leucofrenatus Miranda Ribeiro, 1908: 2 [original description, type locality: Rio das Pedras, Ribeira de Iguape River basin, Brazil]. Microlepidogaster laevior non (Cope, 1884). -Gomes, 1947: 30-32 [misidentified redescription]. Hisonotus leucofrenatus. -Schaefer, 2003: 323 [listed] -Andreata et al., 2006 [karyological description]. -Oyakawa et al., 2007: 94 [comments on ecology and illustration]. -Reis & Carvalho, 2007: 84 [listed]. -Ferraris, 2007: 248 [listed]. -Menezes et al., 2007: 214 [illustrated]. Diagnosis. Hisonotus leucofrenatus differs from all congeners except H. armatus, H. leucophrys, and H. notatus by having the combination of anterior margin of the snout completely covered by odontodes, vs. anterior margin of the snout with a narrow or wide odontode-free band; and large plates in the abdominal median series, usually comprising one series of plates between the lateral abdominal plates, vs. abdominal median series of plates small, with several plate series irregularly arranged between the lateral abdominal plates. Hisonotus leucofrenatus differs from H. armatus, H. leucophrys, and H. notatus by an almost completely dark caudal fin (Fig. 21a) or presence of a faint series of light hyaline spots, forming a vertical bar in the midventral portion (Fig. 20a), vs. a rounded hyaline blotch in the midventral portion in H. notatus (Fig. 21b), and one or more series of conspicuous light vertical bars in the ventral portion in H. armatus (Fig. 21c-d) and H. leucophrys. Hisonotus leucofrenatus further differs from H. armatus and H. leucophyrs by the color pattern of dorsal surface of the head, which is plain dark to light brown, vs. dorsal surface of the head covered by vermiculate and ovoid white and dark spots. Hisonotus leucofrenatus can be also distinguished from H. leucophyrs by the absence of a conspicuous tuft of odontodes on parieto-supraoccipital tip, vs. presence of a conspicuous tuft of odontodes on parietosupraoccipital tip and by the presence of comparatively narrower light horizontal stripes on posterodorsal portion of head, vs. broader light horizontal stripes on the posterodorsal surface of the head. Description. A redescription of Hisonotus leucofrenatus is beyond the scope of this paper. Distribution. Hisonotus leucofrenatus is distributed along the eastern coastal plain of laguna dos Patos in Rio Grande do Sul (Fig. 22) and is sympatric with H. laevior in this region. Outside the boundaries of the laguna dos Patos system, H. leucofrenatus is distributed in the Brazilian Atlantic coastal drainages of São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul States; from the rio Ribeira de Iguape basin (type locality) to the rio Tramandaí system. Remarks. Hisonotus leucofrenatus is found in the rio Tramandaí system, where it has been misidentified by Gomes (1947) as Hisonotus laevior in the resurrection and redescription of the latter. Although the three specimens used in the redescription of Gomes (1947) were not examined, extensive material from the same river (rio Maquiné) and other localities in the rio Tramandaí system were examined. Hisonotus laevior is absent in that system, being H. leucofrenatus the only species of Hisonotus in that region. Also noteworthy is the presence of H. leucofrenatus in the laguna dos Patos system. That species has a patchy distribution in that region contrasted with its wider distributions in neighboring basins. Hisonotus leucofrenatus was described from the rio Ribeira de Iguape basin, a Brazilian Atlantic coastal drainage in southern São Paulo State. No difference was found between examined populations from rio Ribeira de Iguape and rio Tramandaí and all can be diagnosed as above. Recently, a karyologycal characterization of H. leucofrenatus by Andreata et al. (2006), revealed no differences between H. leucofrenatus populations along the Atlantic coastal drainages from rio Ribeira de Iguape to rio Itapocú drainage at northeast Santa Catarina, indicating not only the morphological similarity mentioned here, but karyotype homogeneity. Considering the wide range of this species, an accurate review of H. leucofrenatus populations from Brazilian southeastern coastal drainages should be done to determine with certainty whether these populations are a single species. T. P. Carvalho & R. E. Reis 19 4, Rio Grande do Sul, arroio Água Parada tributary to rio Maquiné. UFRGS 11526, 19, 22.2-30 mm SL, Rio Grande do Sul, Mostardas, lagoa do Bacupari, 30º31’S 50º25’W. Hisonotus taimensis (Buckup, 1981) Figs. 6b and 20b Microlepidogaster taimensis Buckup, 1981: 22 (original description, type locality: novo canal do arroio Taim, Estação Ecológica do Taim, Rio Grande, Rio Grande do Sul, Brasil). -Buckup & Malabarba, 1983 [listed]. -Malabarba, 1989: 150 [listed]. -Grosser et al., 1994 [listed]. Hisonotus taimensis. -Schaefer, 2003: 323 [listed, new combination]. -Bemvenuti & Moresco, 2005: 55 [listed and illustrated]. -Reis & Carvalho, 2007: 84 [listed]. -Ferraris, 2007: 248 [listed]. Diagnosis. Hisonotus taimensis differs from its congeners, except from H. notopagos and H. laevior by the higher number of lateral plates 26-29 (Table 2), vs. 20-25, by the number of predorsal plates 3-4 (usually 4), vs. 2-3, and by vertebral count 31-32, vs. 25-29 vertebrae. Hisonotus taimensis differs from H. notopagos by the presence of a posterior notch articulation Fig. 20. Species of Hisonotus from laguna dos Patos system. a. Hisonotus leucofrenatus, MCP 41630, female, 38.5 mm SL. b. Paratype of Hisonotus taimensis, MAPA 1068, female, 46.5 mm SL. c. Hisonotus charrua, MCP 44500, female, 44.7 mm SL. Material examined. All from Brazil. Laguna dos Patos system: MCN 4640, 1, 29.1 mm SL, Viamão, lagoa Negra at Parque Estadual de Itapuã. MCN 17790, 1, 33.2 mm SL, lagoa do Casamento at southeast coast of Ilha Grande, Palmares do Sul, 30º24’11”S 50º36’56”W. MCN 18137, 5, 25.4-28.9 mm SL, Palmares do Sul, lagoa do Casamento at southern margin, 30º29’S 50º35’W. MCP 21373, 1, 36.4 mm SL, São José do Norte, laguna dos Patos at Barra Falsa, downstream dam, 31º34’19”S 51º27’35”W. MCP 41630, 7, 26.3-39.0 mm SL, São José do Norte, laguna dos Patos at Barra Falsa, upstream dam, 31º34’19”S 51º27’35”W. Outside of laguna dos Patos system. INPA 28608, 10, 33.6-44.0 mm SL, São Paulo, rio Tejuco on road to Itapirapuã Paulista. MCP 11540, 60 + 3 c&s, Santa Catarina, rio Cubatão (norte). MCP 13645, 12, Rio Grande do Sul, Capão da Canoa, Canal at Vila Cornélios between lagoa Itapeva and lagoa dos Quadros. MCP 14834, 8, Santa Catarina, Praia Grande, rio Canoas 8 km from Praia Grande on the road to Mãe dos Homens. MCP 20722, 3, Rio Grande do Sul, creek tributary to rio Maquiné near Maquiné. MCP 21342, 7, Rio Grande do Sul, canal between lagoa Emboaba and lagoa Emboabinha. MCP 29298, 2, Rio Grande do Sul, rio Três Forquilhas on Vila Itati. MCP 32217, 31, Santa Catarina, Jaraguá do Sul, rio Alma tributary of rio Jaraguá. MCP 39094, 4, 38.3-47.6 mm SL, Paraná, Morretes, rio Marumbi tributary of rio Nhundiaquara, 25º29’S 48º49’W. MZUSP 36565, 20, São Paulo, small creek on road from Eldorado to Sete Barras. MZUSP 60220, 11, São Paulo, córrego Fria. UFRGS 4986, Taxonomic review of Hisonotus from the laguna dos Patos system 20 in the rostral plate, vs. absence of a notch articulation in the rostral plate, by having a round caudal peduncle in cross section, vs. a slightly square caudal peduncle in cross section, and by having the area anterior to nares unplated, vs. area anterior to nares covered by dermal plates. Hisonotus taimensis can be distinguished from H. laevior by the narrow cleithral width 18.5-21.3% SL, mean 20.0%, vs. 20.6-24.6% SL, mean 22.9% (Fig. 15), and by the lower body depth at dorsalfin origin 13.3-16.3% SL, mean 15.1%, vs. 16.2-20.8% SL, mean 18.1% (Fig. 16). Description. Morphometrics and meristics in Table 4. This species was described by Buckup (1981) and will not be redescribed here. Distribution and habitat. Hisonotus taimensis is known from localities nearby the laguna Mirim (Fig. 22). This species inhabits, at type locality, slow flowing watercourses with brown waters of muddy and sandy bottom. The individuals are found in between aquatic vegetation of the genus Eichhornia, in grasses or similar kind of submersed vegetation. According to Buckup (1981) the enlarged rostral and pelvic-fin odontodes contribute to them cling the stems and roots of Eichhornia. See Grosser et al. (1994) for detailed description of the species habitat and distribution in the Taim region. Material examined. All from laguna dos Patos system, Rio Grande do Sul, Brazil. Paratypes of M. taimensis: MAPA 1054, 1, 36.3 mm SL, Santa Vitória do Palmar, channel at km 114 on highway BR-471, Estação Ecológica do Taim. MAPA 1055, 10591061, 4, 37.5-51.1 mm SL, Rio Grande, channel at east of lagoa do Jacaré, Estação Ecológica do Taim. MAPA 1070, 1, 26.1 mm SL, Santa Vitória do Palmar, old course of arroio Taim, Estação Ecológica do Taim. MAPA 1013, 1014, 1016, 1018, 1019, 1024, 1026-1028, 1063-1065, 1067-1069, 15, 30.1-47.4 mm SL, Rio Grande, new channel of arroio Taim, Estação Ecológica do Taim. MCN 4835-4844, 10, 34.7-45.9 mm SL, Rio Grande, new channel of arroio Taim, Estação Ecológica do Taim. MCN 7660, 2, 23.950.0 mm SL, Rio Grande, north channel of lagoa do Jacaré, Estação Ecológica do Taim. UFRGS 352-353, 2, 40.4-43.5 mm SL, Rio Grande, new channel of arroio Taim, Estação Ecológica do Taim. UFRGS 396, 1, 37.3 mm SL. Rio Grande, new channel of arroio Taim near the highway BR-471. Non-types: MCP 14467, 2 + 3 c&s, 21.8-42.5 mm SL, Rio Grande, new channel of arroio Taim, Estação Ecológica do Taim. MCP 17417, 27 + 3 c&s, 24.6-41.8 mm SL, Rio Grande, new channel of arroio Taim. UFRGS 697, 2, 32.8-37.4 mm SL, Rio Grande, Estação Ecológica do Taim. UFRGS 2462, 5, 21.1-42.3 mm SL, Rio Grande, Estação Ecológica do Taim, curve in the new channel of arroio Taim on highway BR471. UFRGS 2583, 1, 36.2 mm SL, Rio Grande, Estação Ecológica do Taim, southeast margin of lagoa das Flores. MCN 6474, 1, 46.2 mm SL, Chuí, Barra do Chuí, 33º44’S 53º22’W. CIMC 2341, 2, 28.0-30.7 mm SL, Rio Grande, canal near Estação Ecológica do Taim. CIMC 2405, 67, 20.6-37.3 mm SL, Capão do Leão, canal São Gonçalo near sanga das Traíras. INPA 791, 1, 47.5 mm SL, Rio Grande, arroio Bolacha. INPA 790, 2, 25.1-44.1 mm SL, Rio Grande, arroio Senandes. Fig. 21. Caudal-fin color pattern of some Hisonotus species. a. Hisonotus leucofrenatus, MCP 11540, 42.3 mm SL. b. Hisonotus notatus, MCP 18098, 38.4 mm SL. c. Hisonotus armatus, MCP 34780 40.5 mm SL. d. Hisonotus armatus, MCP 26225, 32.6 mm SL. T. P. Carvalho & R. E. Reis 21 Hisonotus charrua Almirón, Azpelicueta, Casciotta & Litz, 2006 Fig. 20c Hisonotus charrua Almirón et al., 2006: 88 [original description, type locality: Uruguay, Departamento Tacuarembó, río Uruguay basin, Canãda de Los Penã]. -Reis & Carvalho, 2007: 83 [listed]. Reis & Carvalho, 2009: 35 [included in key]. Hisonotus sp. 2. Cramer et al., 2007: 54 [included in molecular phylogeny of Loricariidae]. Diagnosis. Hisonotus charrua differs from its congeners, except from H. armatus, H. leucophrys, H. leucofrenatus, H. laevior, H. notopagos, and H. taimensis by the color pattern of the caudal fin, which has a conspicuous hyaline transversal band composed by clear spots (a second posterior band in larger individuals) in a dark background, vs. hyaline areas not forming a clearly defined transversal bands in the middle portion of caudal fin. Hisonotus charrua is distinguished from H. armatus, H. leucophrys, and H. leucofrenatus by having a narrow naked band without odontodes on the anterior margin of snout, vs. snout completely covered by odontodes; and from H. laevior, H. notopagos, and H. taimensis by the number of lateral plates 23-25 (Table 2), vs. 25-28 plates; by the number of predorsal plates, 3, vs. 3-4 (modally 4) predorsal plates; and by the number of vertebrae 28-29, vs. 30-32 vertebrae. Description. This species was recently described by Almirón et al. (2006) and will not be redescribed here. Distribution and habitat. Hisonotus charrua is widely distributed in the middle and lower portions of the rio Uruguay basin from the northern rio Ijuí drainage in the Rio Grande do Sul State, Brazil, to the southern río Negro drainage in Uruguay. Besides the limits of the rio Uruguay basin, this species is known from the coastal streams of Uruguay, and from the headwaters of Jaguarão and São Gonçalo drainages in the laguna dos Patos system (Fig. 22). The species is sympatric with H. ringueleti Aquino, Miquelarena & Schaefer along its distribution in the middle rio Uruguay basin (Carvalho & Reis, 2009). Hisonotus charrua is collected together with H. nigricauda in several streams tributaries to rio Ibicuí and río Negro drainages. This species inhabits a variety of habitats, usually small to medium size creeks with loose stones, and gravel bottom, with median to rapid-flowing water. Collected associated to marginal vegetation composed by grasses or Echinodorus uruguayensis (Almirón et al., 2006) Remarks. No morphological differences were found between populations of Hisonotus charrua from rio Uruguay basin and the headwaters of rio Jaguarão and rio São Gonçalo drainages in the laguna dos Patos system (Table 5). Cramer et al. (2007) in a molecular phylogeny of Hypoptopomatinae + Neoplecostominae, using a mitochondrial gene (cytochrome Table 4. Morphometrics and meristics of Hisonotus taimensis, including 23 types and 10 non-type specimens. SD = Standard deviation. Types + Non-types n Low High Mean SD Standard length (mm) 33 29.4 51.1 40.2 - Percents of Standard length Head length 33 29.2 35.3 31.6 1.54 Predorsal length 33 40.8 46.4 43.4 1.42 Dorsal-fin spine length 30 19.9 24.5 22.0 1.26 Anal-fin unbranched ray length 32 13.0 17.8 15.8 1.13 Pectoral-fin spine length 33 19.7 24.1 21.9 1.10 Pelvic-fin unbranched ray length 33 13.1 19.8 15.3 1.48 Cleithral width 33 18.5 21.3 20.0 0.67 Thoracic length 33 15.0 18.3 16.1 0.79 Abdominal length 33 17.4 20.5 18.7 0.69 Body depth at dorsal fin origin 33 13.3 16.3 15.1 0.83 Caudal-peduncle length 33 33.4 38.7 35.8 1.34 Caudal-peduncle length 33 8.8 11.0 9.8 0.50 Percents of Head length Snout length 33 42.8 51.6 49.3 1.69 Orbital diameter 33 14.6 18.1 16.2 0.87 Interorbital width 33 35.9 45.1 40.0 2.04 Head depth 33 38.1 47.7 43.2 2.16 Suborbital depth 33 13.5 18.6 16.7 1.05 Mandibular ramus 33 6.6 9.8 8.1 0.63 Meristics Left premaxillary teeth 33 14 20 16.7 1.26 Right premaxillary teeth 33 13 20 16.5 1.73 Left dentary teeth 33 11 19 14.1 1.62 Rigth dentary teeth 32 11 17 14.4 1.46 Left lateral plates 33 26 29 27.4 0.75 Rigth lateral plates 33 26 29 27.2 0.88 Fig. 22. Drainage map of laguna dos Patos system and rio Uruguay basin showing distribution of Hisonotus species. Some symbols represent more than one collecting locality. Open symbols represent type localities. Hisonotus taimensis (triangles); Hisonotus notopagos (circles); Hisonotus leucofrenatus (star); and Hisonotus charrua (square). Taxonomic review of Hisonotus from the laguna dos Patos system 22 c oxidase I), included a sample from the laguna dos Patos system population of H. charrua (Hisonotus sp. 2 - MCP 25139). According to these authors, the H. charrua haplotype from the laguna dos Patos system is sister to H. laevior, while the H. charrua haplotype from rio Uruguay has a more basal position in a clade composed also of H. taimensis and H. armatus. However, there is low resolution in this clade and it seems necessary the inclusion of more samples/genes to unambiguously determine the phyletic status of the H. charrua morphospecies. Material examined. From laguna dos Patos system: Rio São Gonçalo drainage: MCP 25139, 15 + 2 c&s, 32.4-46.4 mm SL, Brazil, Pinheiro Machado, arroio dos Pires on bridge of railroad at Passo dos Pires, 31º38’S 53º27’W. Rio Jaguarão drainage: MCP 44500, 10, 16.9-45.4 mm SL, Brazil, Pedras Altas, creek tributary to arroio Jaguarão at Fazenda Sao Francisco II, 31º53’09”S 53º36’45”W. From rio Uruguay basin: Río Negro drainage: ZVCP 5639, holotype, 49.2 mm SL, Uruguay, Tacuarembó, Cañada de Los Peña, 31º39’05”S 56º12’19”W. AI 165, paratypes, 5, 37.148.7 mm SL, collected with the holotype. MCP 9648, 1, 34.2 mm SL, Brazil, Bagé, rio Negro on bridge of highway BR-293 between Bagé and Aceguá, 31º21’S 54º03’W. MCP 16177, 3, 27.1-36.1 mm SL, Brazil, Bagé, rio Piraizinho on road from Bagé to Dom Pedrito, 31º17’S 54º09’W. MCP 40256, 4 + 1 c&s, 32.8-50.3 mm SL, same locality of holotype. UFRGS 9242, 15, 26.6-38.3 mm SL, Uruguay, Durazno, arroyo Maestre de Campo on road to Polanco de Yí, tributary of río Yí, 33º24’55”S 56º12’06”W. UFRGS 7184, 9 + 2 c&s, 18.0-46.2 mm SL, Uruguay, Rivera, lateral pools and arroyo Corrales on ruta 27, tributary of río Tacuarembó, 31º23’26”S 55º15’14”W. UFRGS 7185, 12, 15.9-39.8 mm SL, Uruguay, Rivera, arroyo Batovi at km 24 of ruta 27, tributary of río Tacuarembó drainage. UFRGS 7186, 3, 15.8-20.6 mm SL, Uruguay, Tacuarembó, arroyo Batovi on km 365 of ruta 5, about 20 km from Tacuarembó, 31º43’S 55º46’W. UFRGS 7187, 3, 16.128.3 mm SL, Uruguay, Rivera, arroyo Cunãpiru on km 12 of ruta 27, río Tacuarembó drainage, 31º02’21”S 55º29’31”W. Other drainages of rio Uruguay: MACN 7593, 1, 40.5 mm SL, Argentina, Entre Ríos, Parque Nacional El Palmar. UFRGS 7977, 2, 32.7-38.5 mm SL, Artigas, Uruguay, arroyo Guaviyú on ruta 3, 30º38’00”S 57º41’16”W. UFRGS 9195, 8, 25.1-40.9 mm SL, Uruguay, Artigas, arroyo Mandiyú on ruta 3, 30º51’55”S 57º39’57”W. AI 176, paratype, 1, 35.9 mm SL, Uruguay, Salto, arroyo Aspinillar at Constitución. Uruguay coastal drainages: MAPA 1969, 15, 14.7-47.2 mm SL, Uruguay, Maldonado, San Carlos, arroyo Maldonado. MCP 40257, 3, 37.3-40.3 mm SL, Uruguay, Canelones, arroyo Tropa Vieja, 34º44’59”S 55º50’46”W. MCP 40255, 38.8 mm SL, Uruguay, Canelones, arroyo Sauce on km 38 of ruta 7, 34º38’48”S 55º58’27”W. Rio Quaraí drainage: AI 186, paratype, 1, 40.5 mm SL, Uruguay, Artigas, arroyo Catalán Grande, 30º50’40”S 56º12’19”W. MCP 11351, 3, 12.8-18.4 mm SL, Brazil, Quaraí, small creek affluent of arroio Garupá, 30º09’S 56º13’W. MCP 35303, 3, 33.8-41.5 mm SL, Brazil, Quaraí, arroio Garupá on road from Quaraí to Harmonia, about 33 km northeast of Quaraí, 30º09’45”S 56º14’08”W. MCP 40904, 23 + 4 c&s, 17.6-45.6 mm SL, Brazil, Quaraí, arroio Quaraí-Mirim on road between Uruguaiana and Quaraí, 30º18’S 56º19’W. UFRGS 7926, 1, 21.1 mm SL, Uruguay, Artigas, arroyo Yucutujá on ruta 3. Rio Ibicuí drainage: MCP 9630, 2, 23.4-33.4 mm SL, Brazil, Dom Pedrito, rio Santa Maria at km 246 of highway BR-293, between Dom Pedrito and Santana do Livramento, 30º59’S 54º42’W. MCP 23090, 1, 44.4 mm SL, Brazil, São Francisco de Assis, arroio Sanga Funda about 15 km southeast from São Francisco de Assis, 29º39’02”S 55º00’06”W. MCP 27539, 4 + 2 c&s, 28.8-46.6 mm SL, Brazil, Jaguari, arroio do Tigre on highway BR-453/ H. charrua types rio Uruguay laguna dos Patos H n Low High Mean SD n Low High Mean SD n Low High Mean SD Standard length (mm) 49.2 6 37.1 49.2 42.8 - 103 22.49 50.53 35.48 - 10 33.8 45.6 37.5 - Percents of Standard length Head length 33.0 6 33.0 36.4 34.6 1.33 103 32.3 39.4 35.4 1.44 10 32.0 34.8 33.8 1.04 Predorsal length 45.9 6 44.8 48.5 46.7 1.28 103 44.2 49.6 47.3 1.20 10 43.6 47.1 46.1 1.22 Dorsal-fin spine length 23.7 6 21.3 25.7 23.5 1.59 103 20.0 29.1 24.1 1.87 10 22.7 26.3 24.8 0.99 Anal-fin unbranched ray length 16.4 6 14.7 18.7 16.7 1.49 102 13.5 19.6 16.8 1.23 10 16.2 19.3 17.6 0.88 Pectoral-fin spine length 25.5 6 23.9 27.5 25.7 1.35 103 21.4 31.0 25.5 1.75 10 24.2 27.9 25.7 1.29 Pelvic-fin unbranched ray length 14.9 6 14.4 20.1 17.3 2.57 103 12.2 23.9 16.5 2.07 10 15.7 21.0 18.9 1.57 Cleithral width 22.8 6 22.8 24.8 24.0 0.78 103 21.8 25.7 23.9 0.88 10 23.0 25.2 24.1 0.68 Thoracic length 16.0 6 15.8 17.3 16.5 0.58 103 14.8 20.0 16.6 0.89 10 15.8 17.9 17.0 0.76 Abdominal length 19.7 6 19.0 20.9 19.8 0.65 103 16.1 22.1 20.0 1.01 10 18.8 20.6 19.8 0.63 Body depth at dorsal-fin origin 19.2 6 19.2 20.9 20.3 0.59 103 16.0 21.6 19.2 1.13 10 19.6 22.0 20.6 0.77 Caudal-peduncle length 33.3 6 31.9 33.8 33.0 0.79 103 28.7 36.4 32.7 1.40 10 32.1 34.9 33.4 0.89 Caudal-peduncle depth 11.5 6 11.5 12.2 12.0 0.26 103 9.6 13.4 11.8 0.82 10 11.6 13.0 12.2 0.50 Percents of Head length Snout Length 48.2 6 47.4 49.8 48.3 0.83 103 43.4 52.4 49.2 1.34 10 45.7 51.4 48.5 1.76 Orbital diameter 15.5 6 14.8 18.0 16.1 1.12 103 13.4 18.7 16.3 1.09 10 14.9 17.8 16.6 0.75 Interorbital width 44.8 6 42.6 45.2 44.0 1.19 103 35.7 47.6 40.7 2.41 10 40.8 47.1 43.9 1.94 Head depth 53.6 6 53.0 55.0 53.9 0.70 103 42.2 54.6 49.2 3.12 10 51.0 58.9 53.3 2.48 Suborbital depth 17.8 6 16.8 19.4 18.1 0.98 103 14.9 21.9 18.2 1.65 10 17.5 22.1 20.4 1.42 Mandibular ramus 7.8 6 7.2 8.7 8.0 0.53 103 6.5 9.8 8.0 0.71 10 7.5 9.7 8.6 0.75 Meristics Left premaxillary teeth 18 5 13 19 17.0 2.35 101 12 20 15.7 1.95 10 14 18 16.5 1.43 Right premaxillary teeth 19 6 14 19 17.3 1.86 101 12 21 15.9 1.87 10 16 20 17.4 1.51 Left dentary teeth 12 6 12 18 15.0 2.19 102 11 19 14.3 1.72 10 14 19 15.7 1.70 Right dentary teeth 15 6 14 17 15.3 1.03 100 11 19 14.4 1.92 10 14 19 16.0 1.56 Left lateral plates 25 6 24 25 24.2 0.41 103 23 25 24.1 0.76 10 23 25 24.0 0.67 Right lateral plates 25 6 23 25 24.0 0.63 103 23 25 24.1 0.76 10 23 25 24.0 0.82 Table 5. Morphometrics and meristics of Hisonotus charrua. SD = Standard deviation and H = holotype. T. P. Carvalho & R. E. Reis 23 Ijucapirama, about 2,5 km northeast from BR-453, 29º28’18”S 54º40’19”W. MCP 27567, 1, 28.6 mm SL, Brazil, Jaguari, creek affluent of rio Tunas on highway BR-453/Ijucapirama, tributary to rio Jaguari, 29º26’27”S 54º35’35”W. MCP 27604, 7, 15.2-35.3 mm SL, Brazil, Jaguari, arroio Capivari on highway BR-453/Jari, tributary to rio Jaguari, 29º21’10”S 54º28’32”W. MCP 27611, 15, 16.5-40.7 mm SL, Brazil, São Francisco de Assis, arroio CaraíPasso on road from São Francisco de Assis to Manuel Viana, 29º31’03”S 55º10’49”W. MCP 27625, 3, 29.8-37.0 mm SL, Brazil, Tupanciretã, rio Santana near Jari, tributary to rio Jaguari, 29º14’33”S 54º16’47”W. MCP 41631, 5, 34.4-39.74 mm SL, Brazil, São Francisco de Assis, rio Inhacunda at São Francisco de Assis going to Manuel Viana, 29º32’51”S 55º08’11”W. MCP 41634, 6, 19.1-37.2 mm SL, Brazil, São Francisco de Assis, creek affluent to rio Inhacunda at São Francisco de Assis about 300 m from potery. UFRGS 2576, 1, 34.5 mm SL, Brazil, Santa Maria, arroio Taquara at km 10 on highway RS-453 between Santa Maria and Santiago. UFRGS 8332, 3, 36.8-39.7 mm SL, Brazil, Bagé, rio Santa Maria on highway BR-293 between Bagé and Dom Pedrito, 31º08’S 54º22’W. UFRGS 8333, 1, 40.4 mm SL, Brazil, Bagé, arroio Santa Maria Chico affluent of rio Santa Maria on highway BR-293, 31º04’S 54º29’W. Rio Ijuí drainage: MCP 9616, 1, 32.5 mm SL, Brazil, Panambi, riacho Raiz Mana at Condor on road from Palmeira das Missões to Panambi, 28º13’S 53º29’W. MCP 16751, 1, 34.5 mm SL, Brazil, Jóia, creek affluent of rio Ijuizinho near Jóia, on road from Eugênio de Castro to Jóia, 28º39’S 54º07’W. MCP 34968, 2 c&s, 19.3-34.9 mm SL, Brazil, Roque Gonzales, arroio Portão, 28º06’21”S 54º58’33”W. MCP 37232, 2 + 2 c&s, 36.1-38.4 mm SL, Brazil, São Pedro do Butiá, arroio Albino, 28º08’10”S 54º55’28”W. MCP 37270, 4, 23.1-33.6 mm SL, Brazil, Dezesseis de Novembro, lageado Araçá, 28º12’23”S 54º56’58”W. UFRGS 4329, 3, 37.8-45.6 mm SL, Brazil, Panambi, rio Caxambu, at km 275 of highway BR-285, 28º19’S 53º39’W. Hisonotus armatus Carvalho, Lehmann, Pereira & Reis, 2008 Figs. 21c-d, 23, and 27d Hisonotus armatus Carvalho et al., 2008: 510 [original description, type locality: Brazil, Rio Grande do Sul, Pedro Osório, arroio Arambaré, about 5 km south of Vila Basílio on the road to Pedro Osório]. Hisonotus nigricauda non (Boulenger, 1981). -Lucena et al., 1994 [listed]. Hisonotus sp. 3. -Cramer et al., 2007: 54 [molecular phylogeny of Loricariidae]. Hisonotus sp. 5. -Reis & Carvalho, 2007: 84 [listed]. -Cramer et al., 2007: 54 [molecular phylogeny of Loricariidae]. Diagnosis. Hisonotus armatus differs from all congeners except H. leucofrenatus, H. leucophrys, and Hisonotus notatus by the combination of having the anterior margin of the snout completely covered by odontodes, vs. anterior margin of the snout with a narrow or wide odontode-free band; and having large plates in the abdominal median series, usually comprising of one series of plates between the lateral abdominal plates, vs. abdominal median series of plates small, with several plate series irregularly arranged between the lateral abdominal plates. Hisonotus armatus differs from H. leucofrenatus and H. notatus by the presence on caudal fin of a series of light hyaline spots, forming one or more vertical light bands (Fig. 21c-d), vs. a rounded hyaline blotch or no hyaline area in the midventral portion of caudal fin (Fig. 21ab). Further differs from H. leucofrenatus and H. notatus by the color pattern of dorsal surface of the head, which is covered by vermiculate and ovoid white and dark spots, vs. dorsal surface of the head plain dark to light brown. Hisonotus armatus differs from H. leucophyrs by the absence of a conspicuous tuft of odontodes on parieto-supraoccipital tip, vs. presence of a conspicuous tuft of odontodes on parietosupraoccipital tip, and by the presence of comparatively narrower light stripes on posterodorsal portion of head, vs. broader light stripes on the posterodorsal surface of the head. Description. Morphometrics and meristics in Table 6. This species was recently described by Carvalho et al. (2008) and will not be redescribed here. Distribution and habitat. Hisonotus armatus is widely distributed in the laguna dos Patos system (Fig. 24). This species inhabits slow to median flowing watercourses, with clear to brown waters over sandy bottom and is found in marginal or submerged aquatic vegetation. Hisonotus armatus is sympatric through its distribution with H. laevior. It was also collected together with H. nigricauda in some localities of the lago Guaíba drainage, with H. vireo in the rio Jacuí drainage, and with H. notopagos in the upper rio Camaquã drainage. Material examined. In addition to the material listed in Carvalho et al. (2008) the following specimens were examined: All from laguna dos Patos system, Rio Grande do Sul, Brazil. MAPA 2624, 10, 21.9-38.0 mm SL, Gravataí, arroio Passo dos Ferreiros. MNRJ 25583, 22, 11.2-37.8 mm SL, Barra do Ribeiro, rio Guaíba at mouth of arroio Ribeiro. MNRJ 25611, 16, 20.8-28.5 mm SL, Porto Alegre, rio Guaíba north of Ponta dos Quatis. MCN 6456, 1, 39.4 mm SL, Três Coroas, arroio José Velho between Canastra Baixa and linha Café Alta. MCN 14236, 8, 14.6-21.8 mm SL, Canela, rio Paranhana at Larangeiro Dam, 29º23’54”S 50º45’26”W. MCN 14795, 1, 33.5, Canela, arroio Casca northeast of UHE Canastra, 29º23’53”S 50º44’37”W. MAPA 1752, 6, 15.0-42.0 mm SL, São Sebastião do Caí, left margin of rio Caí. MCP 41549, 4, 12.8-19.0 mm SL, Cotiporã, rio Carreiro on road between Dois Lageados and Cotiporã, 28º59’43”S 51º45’16”W. MCP 43107, 3, 28.3-30 mm SL, Nova Roma do Sul, rio das Antas downstream to hydroeletric plant UHE Fig. 23. Hisonotus armatus, live specimen, not preserved. Rio Piratini, Rio Grande do Sul, Brazil. Photo: J. F. Pezzi da Silva. Taxonomic review of Hisonotus from the laguna dos Patos system 24 Castro Alves. MCP 43549, 1, 29.2 mm SL, Faria Lemos, córrego Pedrinho near Alcântara, 29º05’31”S 51º37’23”W. MCP 44023, 1, 35.2 mm SL, Bento Gonçalves, rio das Antas near to hydroeletric plant UHE 14 de Julho, 29º04’S 51º40’W. UFRGS 9974, 4, 28.640.3 mm SL, Veranópolis, rio da Prata downstream to hydroeletric plant PCH Jararaca, 28º56’S 51º26’W. MCN 8071, 1, 19.0 mm SL, Triunfo, rio Jacuí at south margin of Ilha das Cabras. Hisonotus notopagos, new species Figs. 4c, 6c, 8c, 25, 26, and 27c Hisonotus sp. 6. -Reis & Carvalho, 2007: 84 [listed]. Holotype. MCP 44517, 45.0 mm SL, female, Brazil, Rio Grande do Sul, Lavras do Sul, small creek tributary of arroio das Lavras on road from Lavras do Sul to Bagé, rio Camaquã drainage, 30º50’18”S 53º55’43”W, 31 Jul 2006, T. P. Carvalho, A. R. Cardoso & J. M. Wingert. Paratypes. All from laguna dos Patos system, Rio Grande do Sul, Brazil. Rio Camaquã drainage: MCP 40757, 4, 35.4-41.6 mm SL, collected with the holotype. ANSP 188701, 3, 39.0-44.7 mm SL, Pinheiro Machado, creek tributary to arroio Boici, at fazenda Chimarrão, 31º13’54”S 53º21’45”W, 25 Jan 2006. L. E. Lanés, M. V. Volcan, A. C. Gonçalves & M. Burns. MCP 25803, 5, 31.8-34.9 mm SL, Bagé, arroio do Tigre, on secondary road between Bagé and Lavras do Sul, 27 Apr 2000, C. A. S. Lucena, J. F. P. Silva & V. A. Bertaco, 31º04’47”S 53º54’03”W. MCP 25924, 1 + 2 c&s, 34.8-44.4 mm SL, Lavras do Sul, arroio da Mantiqueira on secondary road between Bagé and Lavras do Sul, 30º54’24”S 53º58’06”W, 26 Apr 2000, C. A. S. Lucena, J. F. P. Silva & V. A. Bertaco. MCP 40762, 3, 31.6-41.8 mm SL, Lavras do Sul, arroio da Mantiqueira on secondary road between Bagé and Lavras do Sul, 30º54’24”S 53º58’06”W, 31 Jul 2006, T. P. Carvalho, A. R. Cardoso & J. M. Wingert. MCP 40749, 2, 35.5-39.0 mm SL, Bagé, arroio das Traíras on highway BR-153, 31º05’29”S 53º43’33”W, 1 Aug 2006, T. P. Carvalho, A. R. Cardoso & J. M. Wingert. MCP 40763, 1, 51.7 mm SL, Lavras do Sul, small creek tributary to arroio das Lavras, about 2 km from Lavras on road to Bagé, 30º50’02”S 53º53’52”W, 31 Jul 2006, T. P. Carvalho, A. R. Cardoso & J. M. Wingert. MCP 44504, 9, 24.9-39.7 mm SL, Encruzilhada do Sul, arroio Maria Santa, 30º40’36”S 52º32’57”W, 16 Jun 2007, L. E. Lanés & A. C. Gonçalves. MCP 44507, 7, 37.2-45.3 mm SL, Pinheiro Machado, creek tributary to arroio Boici, at fazenda Chimarrão, 31º14’09”S 53º21’39”W. MZUSP 104943, 4, 34.6-36.9 mm SL, Pinheiro Machado, creek tributary to arroio Boici, at fazenda Chimarrão, 31º13’44”S 53º22’18”W, 25 Jan 2006. L. E. Lanés, M. V. Volcan, A. C. Gonçalves & M. Burns. UFRGS 8966, 43 + 3 c&s 17.439.2 mm SL, Brazil, Rio Grande do Sul, Encruzilhada do Sul, small creek in Encruzilhada do Sul tributary to rio Camaquã drainage, 30º35’17”S 52º33’54”W, 14 Dec 2006, J. Anza & R. Hirano. Diagnosis. Hisonotus notopagos differs from its congeners by the absence of a rostral plate posterior notch articulation for the mesethmoid, rostral plate reduced and thin, with an unplated area, medially between the dorsad and ventrad series of odontodes, vs. presence of a rostral plate with the posterior notch articulation with the mesethmoid, rostral plates thick. The new species is also distinguished from other species of Hisonotus, except H. laevior and H. taimensis, by its great number of median plate series 25-27 (Table 2), vs. low number of median plate series 20-25; by having four predorsal plates, Types + Non-types H n Low High Mean SD Standard length (mm) - 63 27 45.9 38.2 - Percent of Standard length Head length 34.4 63 31.7 38.2 34.3 1.22 Predorsal Length 47.4 63 44.0 51.3 46.7 1.27 Dorsal-fin spine length 26.8 63 22.5 27.7 25.2 1.36 Anal-fin unbranched ray length 16.9 63 13.7 17.9 16.2 0.98 Pectoral-fin spine length 27.2 63 20.9 28.1 25.8 1.46 Pelvic-fin spine length 17.0 63 15.1 21.4 18.1 1.68 Cleithral width 25.0 63 21.9 25.4 23.7 0.81 Thoracic length 16.9 63 14.8 18.5 16.6 0.79 Abdominal length 21.9 63 16.4 22.4 20.6 1.13 Body depth at dorsal-fin origin 19.8 63 16.2 20.9 18.5 1.01 Caudal-peduncle length 31.9 63 30.3 35.0 32.8 1.16 Caudal-peduncle length 12.0 63 9.9 12.7 11.2 0.56 Percent of Head length Snout Length 50.2 63 47.1 53.3 50.2 1.32 Orbital diameter 16.7 63 14.8 18.5 16.7 0.86 Interorbital width 40.5 63 37.8 46.5 42.5 1.90 Head depth 49.9 63 43.4 53.8 49.1 2.30 Suborbital depth 18.6 63 15.7 21.6 19.1 1.10 Mandibular ramus 8.6 63 6.9 10.5 8.5 0.75 Meristics Left premaxillary teeth 15 61 14 21 17.7 1.69 Right premaxillary teeth 17 62 15 23 17.7 1.66 Left dentary teeth 16 63 11 19 15.0 1.39 Rigth dentary teeth 15 63 12 20 15.0 1.65 Left lateral plates 24 63 24 25 24.3 0.48 Rigth lateral plates 24 63 23 25 24.3 0.54 Fig. 24. Drainage map of laguna dos Patos system and rio Uruguay basin showing distribution of Hisonotus armatus. Open symbol designates the type locality; some symbols represent more than one collecting locality. Table 6. Morphometrics and meristics of Hisonotus armatus including 40 types plus 20 non-types specimens. SD = Standard deviation and H = holotype. T. P. Carvalho & R. E. Reis 25 vs. three predorsal plates, and by having 30-31 vertebrae, vs. 25-29. Hisonotus notopagos further differs from H. laevior and H. taimensis by having caudal peduncle slightly square in cross section, vs. round peduncle in cross section, and by having the area anterior to the nostrils covered by prenasal plates (Fig. 6c), vs. area anterior to nostrils naked (Fig. 6b). Description. Morphometrics and meristics in Table 7. Adult size large for members of this genus (a female reaching 51.7 mm SL). Body elongate, without conspicuous keels. Caudal peduncle slightly square in cross section. Dorsal profile convex from snout to parieto-supraoccipital tip, slightly convex from that point to dorsal-fin origin; straight and posteroventrally sloped from dorsal-fin origin to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at posterior end of caudal peduncle. Posterior profile of caudal-fin margin concave. Head and snout broad, snout rounded anteriorly in dorsal view, body progressively narrowing posterior to pelvicfin insertion. Snout region anterior to nares not depressed, interorbital region convex. Upper margin of orbit slightly elevated. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6. Pectoral-fin posterior margin almost straight; when depressed tip extending beyond middle of pelvic fin (tip of pectoral-fin reaching just anterior third of pelvic fin in some specimens). Posterior margin of pectoral-fin spine serrate. In juveniles entire length of spine serrate, reduced to distal portion of spine in adults. Pectoral-fin axillary slit present, located below posterior bony margin of cleithral process. Pelvic fin i,5. Tip of depressed fin not reaching anal-fin origin in females, but extending beyond that point in males. Dorsal fin II,7. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Dorsal-fin spinelet present, laterally extended. Anal fin i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Fig. 25. Hisonotus notopagos, MCP 40757, holotype, female, 45.0 mm SL. Small creek tributary of arroio das Lavras on road from Lavras do Sul to Bagé, Lavras do Sul, Brazil, Taxonomic review of Hisonotus from the laguna dos Patos system 32 convex bump at parieto-supraoccipital tip, almost straight and posterodorsally inclined from that point to dorsal-fin origin. Dorsal-fin base straight and posteroventrally sloped, almost straight from posterior end of dorsal-fin base to caudal-fin origin. Ventral profile almost straight from snout tip to anal-fin origin, concave from that point to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at middle of caudal peduncle. Posterior profile of caudal fin slightly concave. Head and snout broad, snout rounded in dorsal view, body progressively narrowing posterior to pelvic-fin insertion. Snout region anterior to nares concave, interorbital region convex. Upper margin of orbit not elevated. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6. Pectoral-fin posterior margin slightly rounded; when depressed tip extending anterior to middle of pelvic fin. Posterior margin of pectoral-fin spine smooth in adults, juveniles with serrae along distal third of pectoral-fin spine. Pectoral-fin axillary slit present, located below posterior bony margin of cleithral process. Pelvic fin i,5. Tip of depressed fin just reaching anal-fin origin in females, but extending beyond that point in males. Dorsal II,7. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Dorsal-fin spinelet present, laterally extended. Anal fin i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Body almost entirely covered by plates except for region overlying opening of swim bladder capsule, area between pectoral girdle and lower lip, region around anus, and area around base of paired fins. Rostral plate with posterior notch articulation with mesethmoid. Rostral plate thickened, with an odontode-free band between dorsad and ventrad series of odontodes (Fig. 35). Snout plates anterior to nares reduced, small unplated area between rostral plate and nostril. Two or three rows of predorsal plates (rarely two). Lateral line incomplete, with gap without pores along middle length of body, posterior portion of lateral line sometimes absent. Median plate series truncated, not reaching posterior end of caudal peduncle (Fig. 4e). Abdominal plates arranged in three rows anteriorly and irregularly arranged between pelvic-fin insertions. Lateral abdominal plates slightly larger and forming regular series. Median abdominal series usually formed by one plate row. Naked area between lateral and median Fig. 34. Scanning electron micrograph of predorsal region of Hisonotus prata, showing the raised tuft of odontodes in the posterior tip of parieto-supraoccipital. MCP 22204, 29.2 mm SL. a. Dorsal view of predorsal region. b. Magnification of raised odontodes. SOC - parieto-supraoccipital; PD - paired predorsal plates; NP - nuchal plate. Fig. 35. Scanning electron micrograph of snout anterior rostral margin of Hisonotus prata, MCP 22204, 29.2 mm SL. a . Anterior view of rostrum; b. Magnification of medial portion. T. P. Carvalho & R. E. Reis 33 abdominal plate series in most specimens (Fig. 8e). Coracoid and cleithrum exposed and covered by odontodes, except for median region of cleithrum between arrector fossae openings and medial region of coracoids. Odontodes on parieto-supraoccipital tip greatly enlarged, raised odontodes arranged in rounded patch, approximately five times larger than those of surrounding areas (Fig. 34). Head, fin-spines, and body plates covered with odontodes, larger on anterior surface of all fin spines, and on ventral and dorsal margin of rostrum. Odontodes medially directed on pelvic-fin thickened unbranched ray. Anteroventral margin of compound pterotic with median-to-large size perforations. Infraorbital canal entering infraorbital series via sphenotic. Lips roundish and papillose, posterior margin of lower lip fimbriate. Maxillary barbel present. Premaxillary and dentary teeth slender proximally and flattened distally; bifid, major (medial) cusp large and rounded, minor (lateral) minute pointed (Fig. 27b). Accessory patch of teeth absent on dentary and premaxilla. Compound ventral hypural plate (hypurals 1-2) and compound dorsal hypural plate (hypurals 3-5) completely fused to each other. Total vertebrae 28 (2 c&s). Color in alcohol. Ground color of dorsal and lateral surfaces dark gray. Dorsal and lateral body surfaces with round dark gray spots. Dorsal and lateral portions of head darker than body, except for lighter cheek region. Ventral surface of body pale yellow, except for scattered chromatophores, these forming spots on ventral surface of caudal peduncle. Region anterior to nares lighter than surrounding areas, but not forming longitudinal light stripes beyond this point. Parietosupraoccipital tip lighter than remaining dorsal surface. Paired, anal, and dorsal fins mostly gray pigmented, with light transverse bands, forming striped pattern. Caudal fin almost completely, except for pair of round to somewhat triangular hyaline areas in middle portion of upper and lower lobes. Unbranched rays of caudal fin with striped pattern of transverse light bands. Ground color in life dark green. Sexual dimorphism. Urogenital papilla, positioned just behind the anal opening in males. Adult males also possess a developed fleshy flap along the dorsal margin of first thickened pelvic-fin ray, that is absent in females. Flap slightly wider basally and progressively narrowing distally. In juvenile males, flap smaller or absent. Males have a longer thickened pelvic-fin unbranched ray that extends beyond anal-fin origin, with pelvic-fin ray reaching just to anal-fin origin in females. Distribution and habitat. Hisonotus prata is endemic to the rio da Prata, tributary of rio das Antas, in the rio Taquari drainage, which is a tributary of the rio Jacuí basin in the laguna dos Patos system (Fig. 32). The rio da Prata, at the type locality, is a rapid flow watercourse, wide and shallow, with an average depth of 0.5 m, shallower in most of its extension, with clear water, rocky bottom and great amounts of submersed vegetation (Fig. 10b). The specimens were caught between aquatic vegetation, individuals being associated with plants of the genus Echinodorus, which form green islands in the faults of the rocky substrate. Hisonotus prata is collected in the vegetation with the undescribed Hypoptopomatinae Eurycheilichthys sp. 2. Etymology. The specific epithet, prata, refers to rio da Prata, the river basin where this species is known. It is treated as a noun in apposition. Hisonotus vireo, new species Figs. 4f, 8f, 27a, 36, 37, and 38 Hisonotus sp. 4. -Reis & Carvalho, 2007: 84 [listed]. Hisonotus sp. 1. -Cramer et al., 2007: 54 [included in molecular phylogeny]. Holotype. MCP 44518, 38.2 mm SL, female, Brazil, Rio Grande do Sul, Caraá, rio dos Sinos, brigde 7 km north of Caraá, road to Fundo Quente, 29º47’S 50º19’W, 12 Jan 1995, L. R. Malabarba, P. A. Buckup, A. R. Cardoso & G. M. Guazelli. Paratypes. All from Brazil, Rio Grande do Sul, rio Jacuí basin, rio dos Sinos drainage: MCP 17643, 6, 11.3-39.2 mm SL; MZUSP 104946, 4, 30.5-39.3 mm SL; collected with the holotype. ANSP 188704, 4, 31.0-34.3 mm SL; MCP 14619, 4 + 3 c&s, 28.3-42.0 mm SL; Caraá, rio do Sinos, about 5 km north of Caraá, 29º46’S 50º20’W, 17 Jan 1991, N. A. Menezes, R. E. Reis & E. H. L. Pereira. MCP 17620, 9, 30.0-40.3 mm SL, Caraá, rio dos Sinos, at Table 9. Morphometrics and meristics of Hisonotus prata. SD = Standard deviation and H = holotype. Types H n Low High Mean SD Standard length (mm) 31.8 16 24.6 33.2 29.3 - Percents of Standard length Head length 37.2 16 36.4 38.6 37.3 0.72 Predorsal length 48.2 16 45.1 49.1 46.9 1.21 Dorsal-fin spine length 22.6 15 22.6 25.5 24.5 0.87 Anal-fin unbranched ray length 18.0 16 17.1 19.4 18.3 0.65 Pectoral-fin spine length 24.3 16 22.0 25.6 24.0 1.01 Pelvic-fin unbranched ray length 16.3 16 15.7 21.3 18.5 1.78 Cleithral width 25.9 16 24.3 27.9 25.9 0.91 Thoracic length 19.2 16 16.2 19.4 17.9 0.91 Abdominal length 20.3 16 18.5 23.8 20.1 1.36 Body depth at dorsal-fin origin 22.7 16 20.4 23.0 21.5 0.81 Caudal-peduncle length 32.3 16 30.2 34.5 32.4 1.33 Caudal-peduncle depth 12.5 16 11.8 13.4 12.4 0.39 Percents of Head length Snout length 46.6 16 45.1 49.5 47.4 1.37 Orbital diameter 15.1 16 15.1 17.9 16.6 0.88 Interorbital width 36.8 16 36.8 40.6 38.7 1.28 Head depth 56.4 16 51.5 57.7 54.5 1.74 Suborbital depth 23.4 16 20.3 23.6 22.2 1.11 Mandibular ramus 8.9 16 8.2 10.3 9.2 0.72 Meristics Left premaxillary teeth 13 16 12 16 14.0 1.03 Right premaxillary teeth 12 16 12 15 13.6 0.89 Left dentary teeth 13 16 11 14 12.9 0.81 Rigth dentary teeth 13 16 12 15 13.1 0.89 Left lateral plates 23 16 22 24 22.9 0.57 Rigth lateral plates 23 16 22 24 22.9 0.68 Taxonomic review of Hisonotus from the laguna dos Patos system 34 praia João Fernandes, about 4 km of Caraá and 5 km of Vila Rodolfo Tetour, 29º45’53”S 50º25’41”W, 12 Jan 1995, L. R. Malabarba, P. A. Buckup, A. R. Cardoso & G. M. Guazelli. Non-type material. All from Brazil, Rio Grande do Sul, laguna dos Patos system. Rio Jacuí drainage: MCP 25459 15, 16.338.7 mm SL and MCP 25719, 15 + 3 c&s, 24.1-39.1 mm SL, Ibarama, lageado do Gringo about 2 km from hidroeletrical power plant Dona Francisca, 29º26’49”S 53º15’36”W. MCP 26568, 6, 26.5-36.8 mm SL, Nova Palma, arroio Caemborá near Caemborá, 29º28’50”S 53º 17’50”W. Rio Taquari drainage: MCP 38766, 15 + 3 c&s, 16.9-38.2 mm SL, Lageado, arroio Saraquá, near Botanic Garden of Lageado, 29º27’42”S 52º00’14”W. UFRGS 8812, 14, 32.5-39.9 mm SL, Lageado, confluence of arroio Pinheirinho with rio Forqueta. 29º19’21”S 52º14’03”W. MCP 41550, 4, 14.6-20.0 mm SL, Cotiporã, rio Carreiro at bridge on road between Dois Lageados and Cotiporã, 29º59’43”S 51º45’16”W. Rio Caí drainage: MAPA 1750, 1, 40,6 mm SL, Nova Petrópolis, rio Cadeia, between Joaneta and Pinhal Alto. MAPA 1751, 2, 33.0-40.0 mm SL, Nova Petrópolis, affluent of rio Cadeia at Picada Café. MAPA 2625, 1, 40.4 mm SL, Nova Petrópolis, arroio Macaquinhos tributary of rio Cadeia. Rio dos Sinos drainage: MAPA 724, 1, 22.9 mm SL, Taquara, rio Rolante between Taquara and Rolante. MAPA 1868, 3, 32.9-41.2 mm Fig. 36. Hisonotus vireo, MCP 44518, holotype, female, 38.2 mm SL. Rio dos Sinos, bridge 7 km north from Caraá, road to Fundo Quente, Caraá, Brazil. T. P. Carvalho & R. E. Reis 35 SL, Santo Antônio da Patrulha, rio dos Sinos, bridge at Santo Antônio da Patrulha. MAPA 2422, 2, 17.3-23.4 mm SL, Taquara, rio da Ilha entre Padilha e rio da Ilha. MAPA 2627, 4, 29.7-41.2 mm SL, Santo Antônio da Patrulha, rio dos Sinos, bridge at Nossa Senhora de Monte Serrat. MCN 6455, 1, 38.7 mm SL, Três Coroas, arroio José Velho between Canastra Alta and Linha Café. MCN 6920, 1, 36.0 mm SL, Três Coroas, arroio Moreira at confluence of arroio Quilombo. MCN 6863, 1, 39,3 mm SL, Três Coroas, arroio Quilombo at Sander. Rio Gravataí drainage: MCP 23875, 3, 29.7-35.2 mm SL, arroio Itajacu, Glorinha, 29º47’34”S 50º42’07”W. Hisonotus cf. vireo: All from Brazil, Rio Grande do Sul, laguna dos Patos system. Rio Jacuí drainage: MCP 26855, 3, 36.0-41.7 mm SL, Júlio de Castilhos, arroio Tipiáia, about 13 km north of Júlio de Castilhos on road to Cruz Alta, 29º06’14”S 53º34’24”W. MCP 41074, 4, 39.044.2 mm SL, arroio Tipiáia (or arroio Passo dos Buracos), on road from Júlio de Castilhos to Cruz Alta, 29º06’48”S 53º39’01”W. Diagnosis. Hisonotus vireo differs from its congeners, except from H. aky, H. brunneus, H. carreiro, H. charrua, H. heterogaster, H. laevior, H. megaloplax, H. montanus, H. nigricauda, H. notopagos, H. prata, H. ringueleti, and H. taimensis by having the anterior margin of the snout with an odontode-free band (Fig. 38); vs. anterior margin of the snout complete covered by odontodes. Differs from those above, except H. carreiro, H. prata, and H. ringueleti by the caudalfin pigmentation, when well defined, composed of a dark background with a pair of hyaline areas, in the middle portion of upper and lower lobes, vs. a dark background without hyaline areas or a transverse hyaline band at the middle of caudal-fin length. Hisonotus vireo differs from H. ringueleti by having the posterior margin of the pectoral-fin spine smooth in specimens between 25 and 35 mm SL, vs. posterior portion of spine serrate in specimens between 25 and 35 mm SL, and by having the abdomen completely covered by abdominal plates (Fig. 8f), vs. abdomen having a large naked area medially on the anterior portion. Differs from H. carreiro and H. prata by the absence of a raised tuft of odontodes on the posterior parieto-supraoccipital tip on adults, juvenile specimens presenting slightly enlarged odontodes, vs. a conspicuous tuft of enlarged odontodes at posterior parietosupraoccipital tip, and median lateral plate series complete, not truncated (Fig. 4f), vs. median lateral plate series truncated (Fig. 4d-e). Description. Morphometrics and meristics in Table 10. Adult size moderate for members of this genus (larger than 40.0 mm in SL). Body stocky, robust, without conspicuous keels. Caudal peduncle round in cross section. Dorsal profile convex from tip of snout to dorsal-fin origin, except for almost straight portion anterior to parieto-supraoccipital. Dorsal-fin base straight and posteroventrally sloped, straight to slightly concave from posterior end of dorsal-fin base to caudal-fin origin. Ventral profile almost straight from snout tip to analfin origin, concave from this point to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at middle of caudal peduncle. Posterior profile of caudal-fin margin pronounced concave. Head and snout broad, snout rounded to slightly pointed in dorsal view, body progressively narrowing posterior of pelvic-fin insertion. Snout region anterior to nares slightly concave, interorbital region convex. Upper margin of orbit slightly elevate. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6, posterior-fin margin almost straight, when depressed tip extending beyond middle of pelvic fin. Posterior margin of pectoral-fin spine smooth in adults, juveniles with serrae along distal half of pectoral-fin spine. Pectoral-fin axillary slit present, located below ventral margin of cleithral process. Pelvic fin i,5. Tip of depressed fin almost reaching anal-fin origin in females, but extending far beyond anal-fin origin in males. Dorsal II,7. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Dorsal-fin spinelet somewhat rounded. Anal fin i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Body almost entirely covered by plates except for region overlying opening of swim bladder capsule, area between pectoral girdle and lower lip, region around anus, and areas around base of paired fins. Rostral plate with posterior notch articulation with mesethmoid. Rostral plate thickened, with odontode-free band between dorsad and ventrad series of odontodes (Fig. 38). Snout plates anterior to nares reduced, small unplated area at lateral portion between rostral plate and prenasal plates. Three rows of predorsal plates. Lateral line incomplete, with gap without pores along middle length of body. Median plate series complete, not truncated (Fig. 4f). Abdominal plates arranged in three rows anteriorly and irregularly arranged between pelvic-fin insertions. Lateral abdominal plates slightly larger and forming regular series. Median abdominal series usually formed by one row, pre-anal shield region formed by small to median size plates (Fig. 8f). Coracoid and cleithrum exposed and covered by odontodes, except for median region of cleithrum between arrector fossae openings and medial region of coracoids. Odontodes on parieto-supraoccipital tip slightly larger than those of surrounding areas, mostly in smaller specimens. Head, fin-spines, and body plates covered with odontodes, larger on anterior surface of all fin spines, and on ventral margin of rostrum, slightly enlarged on dorsal margin. Odontodes medially directed on pelvic-fin unbranched ray. Anterior margin of compound pterotic with median-to-large size perforations. Infraorbital canal entering infraorbital series via sphenotic. Lips roundish and papillose, posterior margin of lower lip fimbriate. Maxillary barbel present. Premaxillary and dentary teeth slender proximally and flattened distally; bifid, major (medial) cusp rounded to spatulate, minor (lateral) minute pointed (Fig. 27a). Accessory patch of teeth absent on dentary and premaxilla. Compound ventral hypural plate (hypurals 1-2) and compound dorsal hypural plate (hypurals 3-5) completely fused to each other, with slight median notch on the posterior margin of caudal-fin skeleton. Total vertebrae 27-29 (3 c&s). Taxonomic review of Hisonotus from the laguna dos Patos system 36 Color in alcohol. Ground color of dorsal and lateral surfaces of body light to dark brown. Dorsal and lateral surfaces of head darker than body, except for light area in ventrolateral region contrasting with dark blotches. Region anterior to nares lighter than surrounding areas, forming paired longitudinal light stripes from snout tip to posterior end of parieto-supraoccipital, bifurcating and inconspicuous posterior to that point. Midlateral surface of body darkish, forming darker brown wide longitudinal stripe above lateral line. Ventral surface of body pale yellow, sometimes with scattered round blotches, mostly on cheeks and belly. Unbranched rays of pectoral, pelvic, dorsal, and anal fins mostly brown pigmented, except for narrow lighter spots, forming striped pattern. Branched rays of these fins mostly hyaline except for darker transverse bands. Caudal fin mostly dark brown, except for pair of hyaline areas, somewhat triangular, on anterior portion of upper and lower lobes. Hyaline areas sometimes contacting each other at middle of caudal fin, forming hour-glass-like mark. Posterior portion of branched rays of caudal-fin hyaline. Unbranched rays of caudal fin with striped pattern of transverse light bands. In life, ground color of dorsum and flanks bright green (Fig. 37). Sexual dimorphism. Urogenital papilla positioned just behind the anal opening in males. Adult males also possess a developed fleshy flap along the dorsal margin of first thickened pelvic-fin ray, that is absent in females. Flap slightly Types Non-types H n Low High Mean SD n Low High Mean SD Standard length (mm) 38.2 28 29.0 42.0 34.5 - 39 27.1 44.3 37.0 - Percents of Standard length Head length 33.8 28 32.2 35.7 33.9 0.91 39 32.1 38.4 34.5 1.49 Predorsal Length 45.8 28 42.7 47.7 45.0 1.18 39 43.0 48.9 45.9 1.25 Dorsal-fin spine length 28.3 27 23.6 29.8 27.5 1.35 39 21.8 28.4 25.3 1.63 Anal-fin unbranched ray length 18.4 28 15.5 20.9 18.7 1.19 39 16.4 20.4 18.1 0.87 Pectoral-fin spine length 28.5 28 25.4 29.3 27.2 1.06 39 23.4 29.3 26.4 1.42 Pelvic-fin unbranched ray length 16.6 28 13.8 21.3 17.7 1.97 39 13.9 22.3 17.0 1.85 Cleithral width 23.8 28 21.8 25.4 23.5 0.73 39 22.2 25.8 24.0 0.95 Thoracic length 17.4 28 15.8 18.7 17.4 0.63 39 15.6 19.8 17.6 0.74 Abdominal length 18.8 28 17.7 20.6 19.1 0.64 39 17.1 20.8 19.2 0.86 Body depth at dorsal-fin origin 21.9 28 18.0 22.0 20.6 0.82 39 18.9 22.9 20.6 0.82 Caudal-peduncle length 32.5 28 30.5 35.2 33.5 1.22 39 30.6 37.6 33.7 1.51 Caudal-peduncle depth 14.0 28 12.8 14.5 13.7 0.48 39 11.8 15.2 13.1 0.81 Percents of Head length Snout Length 49.6 28 47.7 52.3 49.4 1.18 39 45.9 50.2 48.3 1.16 Orbital diameter 17.0 28 15.8 19.7 17.6 0.96 39 15.7 20.0 17.3 0.99 Interorbital width 42.5 28 38.8 45.7 42.6 1.51 39 38.3 47.1 42.0 2.27 Head depth 57.2 28 51.8 58.9 54.9 2.16 39 49.4 59.0 54.0 2.12 Suborbital depth 20.9 28 17.6 21.3 19.7 0.99 39 17.4 22.7 20.0 1.30 Mandibular ramus 8.6 28 7.0 10.5 8.8 0.87 39 7.3 10.1 8.8 0.67 Meristics Left premaxillary teeth 18 28 13 20 16.0 1.88 38 11 20 15.7 2.20 Right premaxillary teeth 18 28 13 19 15.9 1.81 37 11 20 15.5 2.29 Left dentary teeth 18 28 13 19 15.1 1.82 38 11 18 14.1 2.12 Rigth dentary teeth 16 28 12 19 14.8 1.85 37 10 18 14.2 2.07 Left lateral plates 23 28 23 24 23.4 0.50 39 22 24 23.4 0.68 Rigth lateral plates 23 28 22 24 23.3 0.66 39 22 24 23.4 0.54 Table 10. Morphometrics and meristics of Hisonotus vireo. SD = Standard deviation and H = holotype. Fig. 37. Hisonotus vireo, UFRGS 8812, live specimen, female, from confluence of arroio Pinheirinho with rio Forqueta, Lageado, Brazil (note isopod parasite Braga fluviatilis, Cymothoidae, on dorsal fin). Photo: L. R. Malabarba. T. P. Carvalho & R. E. Reis 37 wider basally and progressively narrowing distally. Presence of a fleshy flap on medial portion of the first and second branched rays of pelvic fin. In juvenile males, flaps are smaller or absent. Males have a longer pelvic fin that extends far beyond the anal-fin origin, with the pelvic fin never reaching the anal-fin origin in females. Distribution and habitat. Hisonotus vireo is widely distributed in the rio Jacuí basin from the eastern rio Gravataí and rio dos Sinos drainages to the lower portions of the western rio Jacuí drainage (Fig. 32). In the rio Jacuí basin, the new species was not found in the southern tributaries or in the headwaters of rio Jacuí and rio Taquari drainages. This species inhabits medium to fast flow watercourses, with clear waters running over sandy or rocky bottoms, being collected in marginal or aquatic submersed vegetation. Hisonotus vireo is sympatric along almost its entire distribution with H. armatus. Geographic variation. The specimens from arroio Tipiáia (MCP 26855 and MCP 41074) differ to a certain degree in pigmentation from other populations in the rio Jacuí basin. These specimens of arroio Tipiáia differ from other conspecifics by the darker pigmentation of caudal fin, which present reduced hyaline areas to complete dark brown in some specimens, contrasting with a pair of hyaline triangular areas on upper and lower lobes and no pigments at posterior portion of caudal fin rays. The condition observed in the caudal-fin pigmentation of specimens from arroio Tipiáia, resemble that of Hisonotus brunneus and H. heterogaster. However, when well defined, the hyaline areas in the specimens from arroio Tipiáia clearly are alike the triangular hyaline areas presented by other populations of H. vireo. A PCA was performed to compare morphometric data of that population to others of H. vireo, in rio Jacuí, rio Taquari, and rio dos Sinos (type locality). No discriminant differences were found between the populations of H. vireo, except when compared with the species H. brunneus (Fig. 39). For these reasons, we tentatively identified these specimens from arroio Tipiáia as belonging to the species H. vireo, and restricted the type series to specimens collected close to the type locality. Etymology. The specific epithet, vireo, from the Latin meaning “greenish”, in allusion to the greenish coloration of live specimens of this species. Fig. 38. Scanning electron micrograph of snout anterior rostral margin of Hisonotus vireo, MCP 17643, 38.5 mm SL. a. Anterior view of rostrum; b. Magnification of medial portion. Fig. 39. Scatter plot of Principal Component Analysis of 17 morphometric data of Hisonotus species from rio Jacuí basin. Red crosses = Hisonotus brunneus; brown dots = Hisonotus heterogaster; dark green exes = Hisonotus vireo (type specimens/ rio dos Sinos); light green diamonds = Hisonotus vireo (non types rio Taquari/rio Jacuí); blue squares = Hisonotus cf. vireo. Taxonomic review of Hisonotus from the laguna dos Patos system 38 Hisonotus brunneus, new species Figs. 4g, 8g, 40, and 41 Hisonotus sp. 3. -Reis & Carvalho, 2007: 84 [listed]. Holotype. MCP 44516, 41.5 mm SL, female, Brazil, Rio Grande do Sul, Cruz Alta, rio Passo Novo, on road from Cruz Alta to Ibirubá, rio Jacuí drainage, 28º38’43”S 53º33’35”W, 2 Apr 1999, R. E. Reis, E. H. L. Pereira & V. A. Bertaco. Paratypes. All from Brazil, Rio Grande do Sul, rio Jacuí drainage: MCP 22701, 27 + 3 c&s, 26.3-41.1 mm SL, collected with the holotype. ANSP 188705, 4, 34.6-39.0 mm SL; MCP 41072, 13, 29.0-41.0 mm SL; MZUSP 104947, 4, 37.2-40.9 mm SL; collected at the type locality, 13 Dec 2006, T. P. Carvalho & A. R. Cardoso. Diagnosis. Hisonotus brunneus differs from its congeners, except from H. aky, H. brunneus, H. carreiro, H. charrua, H. heterogaster, H. laevior, H. megaloplax, H. montanus, H. nigricauda, H. notopagos, H. prata, H. ringueleti, and H. taimensis by having Fig. 40. Hisonotus brunneus, MCP 44516, holotype, female, 41.5 mm SL. Rio Passo Novo on road from Cruz Alta to Ibirubá, Cruz Alta, Brazil. T. P. Carvalho & R. E. Reis 39 the anterior portion of snout with an odontode-free band (Fig. 41), vs. snout completely covered with odontodes. It differs from those above, except from H. laevior, H. taimensis, H. megaloplax, and H. heterogaster by a darkly pigmented caudal fin, without a hyaline area in the middle portion, vs. caudal fin with hyaline areas in the middle portion. Hisonotus brunneus differs from H. heterogaster, H. laevior, H. megaloplax, and H. taimensis by having the abdominal median plate series large, one or two series of plates regularly arranged between the lateral abdominal series (Fig. 8g), vs. abdominal median plate series with several small plates irregularly arranged between the lateral abdominal plates in H. laevior and H. taimensis, or abdominal medium series absent, midline portion of the belly naked in H. heterogaster (Fig. 8h) or covered by the enlarged lateral series in H. megaloplax, respectively. Also, it differs from H. heterogaster, H. laevior, H. megaloplax, and H. taimensis by having median lateral plate series incomplete, truncated (Fig. 4g), vs. median lateral plate series complete, not truncated. Description. Morphometrics and meristics in Table 11. Adult size small to median for members of this genus (usually less than 40.0 mm SL). Body relatively stocky, robust, without conspicuous keels. Caudal peduncle round in cross section. Dorsal profile convex from tip of snout to parietosupraoccipital tip, slightly convex from that point to dorsalfin origin. Dorsal-fin base straight and posteroventrally sloped, straight from posterior end of dorsal-fin base to caudal-fin origin. Ventral profile almost straight from snout tip to anal-fin origin, concave from this point to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at posterior end of caudal peduncle. Posterior profile of caudal fin concave to slightly forked. Head and snout broad, snout rounded to slightly square in dorsal view, body progressively narrowing posterior of pelvic-fin insertion. Snout region anterior of nares concave, interorbital region convex. Upper margin of orbit slightly elevated. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6. Pectoral-fin posterior margin slightly rounded to straight, when depressed tip extending just anterior to middle of pelvic fin. Posterior margin of pectoral-fin spine smooth in adults, juveniles with feeble serrae along distal third of pectoralfin spine. Pectoral-fin axillary slit present, located below posterior bony margin of cleithral process. Pelvic fin i,5. Tip of depressed fin just reaching anal-fin origin in females, but extending far beyond that point in males. Dorsal-fin II, 7. Dorsalfin origin located slightly posterior to vertical through pelvicfin origin. Dorsal-fin spinelet slight-laterally extended. Anal i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Body almost entirely covered by plates except for region overlying opening of swim bladder capsule, area between pectoral girdle and lower lip, region around anus, and area around base of paired fins. Rostral plate with posterior notch articulation of mesethmoid. Rostral plate thickened, with odontode-free area between dorsad and ventrad series of odontodes (Fig. 41). Snout plates anterior to nares reduced, small unplated area at lateral portion between rostral plate and nostril. Three rows of predorsal plates. Lateral line incomplete, with gap without pores along middle length of body. Median plate series truncated, not reaching posterior end of caudal peduncle (Fig. 4g). Abdominal plates arranged in three rows anteriorly and irregularly arranged between pelvic-fin insertions. Lateral abdominal plates slightly larger and forming regular series. Median abdominal series formed by one or two plate series, pre-anal shield region formed by median to large plates (Fig. 8g). Coracoid and cleithrum exposed and covered by odontodes, except for median region of cleithrum between arrector fossae openings and medial region of coracoids. Odontodes on parieto-supraoccipital tip slightly larger than those of surrounding areas, most in smaller specimens. Head, fin-spines, and body plates covered with odontodes, larger on anterior surface of all fin spines, and on ventral margin of rostrum slightly enlarged in dorsal margin. Odontodes medially directed on pelvic-fin unbranched ray. Anterior margin of compound pterotic with median-to-large size perforations. Infraorbital canal entering infraorbital series via compound pterotic. Lips roundish and papillose, posterior margin of lower lip fimbriate. Maxillary barbel present. Premaxillary and dentary teeth slender proximally and flattened distally; bifid, major (medial) cusp large and rounded, minor (lateral) minute pointed. Accessory patch of teeth absent on dentary and premaxilla. Fig. 41. Scanning electron micrograph of snout anterior rostral margin of Hisonotus brunneus, MCP 22701, 41.1 mm SL. a. Anterior view of rostrum; b. Magnification of medial portion. Taxonomic review of Hisonotus from the laguna dos Patos system 40 extends far beyond anal-fin origin, with pelvic-fin reaching just to anal-fin origin in females. Distribution and habitat. Hisonotus brunneus is endemic to the upper rio Jacuí basin, in the laguna dos Patos system. The new species is only known from the rio Passo Novo, an affluent of the rio Ingaí, tributary to the upper portion of rio Jacuí basin (Fig. 32). This species inhabits a median to fast flowing watercourse, with clear to brown waters running over sand or stones. Being found in marginal submersed grasses, H. brunneus is collected in the vegetation together with Eurycheilichthys limulus Reis & Schaefer. The rio Passo Novo at the type locality is a small creek, about 3 m wide and shallow with a maximum depth of 0.5 m, at 400 m above sea level. The stream is somewhat polluted, crossing the urban area of Cruz Alta, and has deforested riparian vegetation and amounts of rubbish along the margins. Etymology. The specific epithet brunneus, from the Latin, means tawny and refers to overall brownish pigmentation of the species. It is treated as an adjective. Hisonotus heterogaster, new species Figs. 4h, 8h, 42, and 43 Holotype. MCP 44514, 43.0 mm SL, female, Brazil, Rio Grande do Sul, Júlio de Castilhos, arroio Felício on road from Nova Palma to Júlio de Castilhos, 29º19’04”S 53º37’54”W, 12 Dec 2006, T. P. Carvalho & A. R. Cardoso. Paratypes. All from Brazil, Rio Grande do Sul, rio Jacuí drainage: ANSP 188706, 3, 37.1-40.7 mm SL; MCP 41073, 5 + 2 c&s, 37.444.3 mm SL; MZUSP 104948, 3, 40.8-41.3 mm SL; collected with the holotype. MCP 26802, 1, 43.0 mm SL, collected at type locality, 28 Nov 2000, L. R. Malabarba, V. A. Bertaco, M. A. Azevedo, J. R. H. Bastos & C. Ricken. Diagnosis. Hisonotus heterogaster differs from its congeners, except from H. aky, H. brunneus, H. carreiro, H. charrua, H. heterogaster, H. laevior, H. megaloplax, H. montanus, H. nigricauda, H. notopagos, H. prata, H. ringueleti, and H. taimensis by having the anterior margin of the snout with an odontode-free band (Fig. 43), vs. anterior margin of the snout completely covered by odontodes. It differ from those above by its lack of the median abdominal plate series, leaving a large naked abdominal area, plates at ventral midline restricted to small platelets at pre-anal shied region (Fig. 8h); vs. presence of the median abdominal plate series, pre-anal shield region plated. Description. Morphometrics and meristics in Table 12. Adult size moderate to large for members of this genus (larger than 40.0 mm in the SL). Body robust, without conspicuous keels. Caudal peduncle round in cross section, slightly flattened dorsally. Dorsal profile convex from tip of snout to dorsal-fin origin. Dorsal-fin base straight and posteroventrally sloped, straight from posterior end of Compound ventral hypural plate (hypurals 1-2) and compound dorsal hypural plate (hypurals 3-5) completely fused to each other, with small median notch on the posterior margin of caudal-fin skeleton. Total vertebrae 27-28 (2 c&s). Color in alcohol. Ground color of dorsal and lateral surfaces pale to dark brown. Dorsal and lateral body surfaces with rounded gray spots. Dorsal and lateral portions of head darker than body, except for lighter area in ventrolateral region contrasting with dark blotches. Ventral surface of body pale yellow, except for scattered chromatophores. Region anterior to nares lighter than surrounding areas, forming longitudinal light stripe from snout tip to posterior end of parietosupraoccipital. Unbranched rays of fins mostly brown pigmented, sometimes presenting hyaline transverse bands, forming striped pattern. Caudal fin almost completely brown, except for hyaline area on posterior end of upper caudal fin rays. Unbranched rays of caudal fin with alternating transverse light bands and dark areas. General color pattern in life, dark green. Sexual dimorphism. Urogenital papilla, positioned just behind the anal opening in males. Adult males also possess a developed fleshy flap along the dorsal margin of first thickened pelvic-fin ray, that is absent in females. Flap slightly wider basally and progressively narrowing distally. Presence of a fleshy flap in the medial portion of the first and second branched rays of pelvic fin. In juvenile males, flaps smaller or absent. Males have longer pelvic-fin unbranched ray that Table 11. Morphometrics and meristics of Hisonotus brunneus. SD = Standard deviation and H = holotype. Types H n Low High Mean SD Standard length (mm) 41.5 20 31.8 41.5 35.9 - Percent of Standard length Head length 35.3 20 32.9 37.9 35.6 1.22 Predorsal length 48.5 20 45.2 49.3 47.4 1.22 Dorsal-fin spine length 23.8 20 22.6 25.4 23.8 0.79 Anal-fin spine length 17.2 20 14.9 17.2 16.3 0.72 Pectoral-fin spine length 25.8 20 24.4 26.8 25.4 0.62 Pelvic-fin spine length 15.8 20 15.2 19.0 17.1 1.07 Cleithral width 25.5 20 23.4 26.2 24.8 0.69 Thoracic length 16.4 20 15.9 18.4 17.4 0.61 Abdominal length 20.1 20 18.2 20.4 19.6 0.67 Body depth at dorsal-fin origin 20.9 20 19.4 21.6 20.4 0.60 Caudal-peduncle length 32.9 20 30.3 34.9 33.0 1.37 Caudal-peduncle length 11.8 20 11.0 13.4 12.0 0.58 Percent of Head length Snout Length 47.9 20 47.8 54.8 50.3 1.62 Orbital diameter 15.0 20 14.1 16.9 15.5 0.66 Interorbital width 42.4 20 40.1 45.8 42.8 1.48 Head depth 53.4 20 48.9 54.9 51.6 1.46 Suborbital depth 20.3 20 19.1 24.0 21.0 1.07 Mandibular ramus 9.1 20 7.2 9.5 8.5 0.65 Meristics Left premaxillary teeth 19 20 15 21 17.9 1.35 Right premaxillary teeth 18 20 16 20 17.8 1.36 Left dentary teeth 17 20 14 19 16.0 1.56 Rigth dentary teeth 15 20 13 20 16.0 1.59 Left lateral plates 23 20 22 24 22.9 0.55 Rigth lateral plates 23 20 22 23 22.7 0.49 T. P. Carvalho & R. E. Reis 41 dorsal-fin base to caudal-fin origin. Ventral profile somewhat concave from snout tip to posterior portion of head, almost straight from that point to anal-fin origin. Concave at anal fin base and straight from that point to caudal-fin origin. Greatest body depth at dorsal-fin origin. Least body depth at middle of caudal peduncle. Posterior profile of caudal-fin margin slightly concave. Head and snout broad, snout rounded to slightly pointed in dorsal view, body progressively narrowing posterior to pectoral-fin insertion. Snout region anterior to nares straight, not depressed; interorbital region straight to slightly convex. Upper margin of orbit not elevated. Eye dorsolaterally positioned. Iris operculum present. Pectoral fin I,6. Pectoral-fin posterior margin almost straight, when depressed tip extending beyond middle of pelvic fin. Posterior margin of pectoral-fin spine smooth in adults, smaller specimens with feeble serrae along posterior third of pectoral-fin spine. Pectoral-fin axillary slit present, located below ventral margin of cleithral process. Pelvic fin i,5. Tip of depressed fin just reaching anal-fin origin in females, but extending far beyond that point in males. Dorsal II,7. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Dorsal-fin spinelet laterally extended. Anal fin i,5. First anal-fin pterygiophore exposed anterior to anal fin. Adipose fin absent. Caudal fin i,14,i. Body almost entirely covered by plates except for region overlying opening of swim bladder capsule, area between pectoral girdle and lower lip, region around anus, and base of paired fins, and belly region between lateral abdominal plate series. Rostral plate with posterior notch articulation with mesethmoid. Rostral plate thickened, with odontode-free area between dorsad and ventrad series of odontodes (Fig. 43). Fig. 42. Hisonotus heterogaster, MCP 44514, holotype, female, 43.0 mm SL. Arroio Felício on road from Nova Palma to Júlio de Castilhos, Júlio de Castilhos, Brazil. Taxonomic review of Hisonotus from the laguna dos Patos system 48 Liedke A. M. R. 2006. Filogenia e Filogeografia gênero Eurycheilichthys (Siluriformes: Loricariidae. Unpusblished Master Thesis. Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil. Lucena, C. A. S., A. S. Jardim & E. S. Vidal. 1994. Ocorrência, distribuição e abundância da fauna de peixes da praia de Itapuã, Viamão, Rio Grande do Sul, Brasil. Comunicações do Museu de Ciências e Tecnologia da PUCRS, 7: 3-27. Malabarba, L. R. 1989. Histórico sistemático e lista comentada das espécies de peixes de água doce do sistema da laguna dos Patos, Rio Grande do Sul, Brasil. Comunicações do Museu de Ciências da PUCRS, 2: 107-179. Malabarba, L. R. & E. A. Isaia. 1992. The fresh water fish fauna of the rio Tramandaí drainage, Rio Grande do Sul, Brazil, with a discussion of its historical origin. Comunicações do Museu de Ciências da PUCRS, 5: 197-223. Menezes, N. A., S. H. Weitzmann, O. T. Oyakawa, F. C. T. Lima, R. M. C. Castro & M. J. Weitzmann. 2007. Peixes de água doce da Mata Atlântica. Museu de Zoologia/USP, São Paulo, Brazil. 407p. Miranda-Ribeiro, A. 1908. Peixes da Ribeira. Resultados de excursão do Sr. Ricardo Krone, membro correspondente do Museu Nacional do Rio de Janeiro. Kosmos, 5: 1-5. Miranda-Ribeiro, A. 1911. Fauna brasiliense. Peixes. Tomo IV (A) [Eleutherobranchios Aspirophoros]. Arquivos do Museu Nacional Rio de Janeiro, 16: 1-504. Oyakawa, O. T., A. Akama, K. C. Mautari & J. C. Nolasco. 2006. Peixes de riachos da Mata Atlântica nas Unidades de Conservação do Vale do Rio Ribeira de Iguape no Estado de São Paulo. Editora Neotrópica, São Paulo, Brazil, 201p. Papavero, N. 1973. Essays on the history of Neotropical Dipterology, with special reference to collectors (1750-1905), V. II. Museu de Zoologia Universidade de São Paulo, São Paulo, Brazil. Regan, C. T. 1904. A monograph of the fishes of the family Loricariidae. Transactions of the Zoological Society of London, 17: 191-350. Reis, R. E. & T. P. Carvalho. 2007. Hypoptopomatinae. Pp. 8384. In: Buckup, P. A., N. A. Menezes & M. S. Ghazzi (Eds.). Catálogo das espécies de peixes de água doce do Brasil. Museu Nacional (Série Livros), Rio de Janeiro, 195p. Reis, R. E. & S. A. Schaefer. 1992. Eurycheilichthys pantherinus (Siluriformes: Loricariidae), a new genus and species of Hypoptopomatinae from Southern Brazil. Copeia, 1992: 215223. Reis, R. E. & S. A. Schaefer. 1998. New cascudinhos from southern Brazil: systematics, endemism, and relationships (Siluriformes, Loricariidae, Hypopotopomatinae). American Museum Novitates, 3254: 1-25. Retzer, M. E., L. G. Nico & F. R. Provenzano. 1999. Two new species of Acestridium (Siluriformes: Loricaridae) from southern Venezuela, with observations on camouflage and color change. Ichthyological Exploration of Freshwaters, 10: 313-326. Ribeiro, M. F., A. Köhler, A. Dupont & E. C. G. Azevedo. 2007. Os peixes do rio Pardinho. Santa Cruz do Sul, EdUnisc. Rodriguez, M. S. & R. E. Reis. 2008. Taxonomic review of Rineloricaria (Loricariidae: Loricariinae) from the Laguna dos Patos drainage, Southern Brazil, with the descriptions of two new species and the proposition of two species groups. Copeia, 2008: 333-349. Ryan, P. D., D. A. T. Harper & J. S. Whalley. 1995. PALSTAT, Statistics for paleontologists. Chapman & Hall, London, England. Saccol-Pereira, A., P. C. C. Milani & C. B. Fialho. 2006. First record of Acestrorhynchus pantaneiro Menezes 1992 (Characiformes, Acestrorhynchidae) in the system of the laguna dos Patos, Rio Grande do Sul, Brazil. Biota Neotropica, 6: 14. Schaefer, S. A. 1991. Phylogenetic analysis of the loricariids subfamily Hypoptopomatinae (Pisces: Siluroidei: Loricariidae), with comments on generic diagnoses and geographic distribution. Zoological Journal of the Linnean Society, 102: 1-41 Schaefer, S. A. 1997. The Neotropical cascudinhos: Systematics and biogeography of the Otocinclus catfishes (Siluriformes: Loricariidae). Proceedings of the Academy of Natural Sciences of Philadelphia, 148: 1-120. Schaefer, S. A. 1998. Conflict and resolution: Impact of new taxa on phylogenetic studies of the neotropical cascudinhos (Siluriformes: Loricariidae). Pp. 375-400. In: Malabarba, L. R., R. E. Reis, R. P. Vari, C. A. S. Lucena & Z. M. S. Lucena (Eds.). Phylogeny and Classification of Neotropical Fishes. Porto Alegre, Edipucrs, 603p. Schaefer, S. A. 2003. Loricariidae - Hypoptopomatinae (Armored catfishes). Pp. 321-329. In: Reis, R. E., S. O. Kullander & C. J. Ferraris, Jr. (Eds.). Checklist of Freshwater Fishes of the South and Central America. Porto Alegre, Edipucrs, 729p. Schwarzbold, A. & A. Schäfer, 1984. Gênese e Morfologia das Lagoas Costeiras do Rio Grande do Sul - Brasil. Amazoniana, 9: 87-104. Strauss, R. E. 1985. Evolutionary allometry and variation in body form in the South American catfish genus Corydoras (Callichthyidae). Systematic Zoology, 34: 381-396. 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. Accepted November 26, 2010 Published March 31, 2011