Lynceus amplopedia sp. nov., A New Laevicaudatan Clam Shrimp with Asymmetrically Modified Thoracopods from Yunnan, China (Crustacea: Branchiopoda)

© 2019 Academia Sinica, Taiwan Open Access Lynceus amplopedia sp. nov., A New Laevicaudatan Clam Shrimp with Asymmetrically Modified Thoracopods from Yunnan, China (Crustacea: Branchiopoda) Shusen Shu1,2,3, Zandra M. S. Sigvardt4, Xiaoyong Chen2,3, Jørgen Olesen4, D. Christopher Rogers5,*, and La-orsri Sanoamuang1,6,* 1Applied Taxonomic Research Center, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand 2Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar 3Kunming Institute of Zoology, 650223, Chinese Academy of Sciences, Kunming, China 4Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark 5Kansas Biological Survey and the Natural History Museum (Biodiversity Institute), Kansas University, Kansas 66047-3759, USA. *Correspondence: E-mail: [email protected] 6International College, Khon Kaen University, Khon Kaen 40002, Thailand. *Correspondence: E-mail: [email protected] Received 11 May 2019 / Accepted 26 July 2019 / Published 18 September 2019 Communicated by Benny K.K. Chan Laevicaudata has a nearly global distribution, but only a few records from China. We present a new Lynceus (Crustacea: Branchiopoda: Laevicaudata) species, Lynceus amplopedia sp. nov., from Yunnan, China, which shows significant left-right differences in some non-clasper thoracopods. It can be distinguished from all congeners by asymmetrically modified thoracopods III–VI. In the ‘explanate modified’ side (usually the left side, occasionally the right) the following modifications are present: endites 4, 5, and endopod enlarged (explanate) (thoracopods III and IV); exopod with 14–15 digitiform processes dorsomedially (thoracopods V and VI); and broad muscular basis (thoracopods III–V). The following modifications are seen in the thoracopods of the opposing ‘spinose modified’ side (usually the right side, occasionally the left): endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI), and broad muscular basis (thoracopod V). Other unique characters of the new species include: male and female rostrum sinuate, compound eyes protruding, male claspers with endopod constricted, and endite 3 with two scale patches. We suggest the modified thoracopods may be involved in mating and/or respiration. The diversity of Chinese Lynceus is also discussed. Key words: Laevicaudata, Diversity, New species, Modified thoracopods, Lateral asymmetry. Citation: Shu S, Sigvardt ZMS, Chen X, Olesen J, Rogers DC, Sanoamuang L. 2019. Lynceus amplopedia sp. nov., a new laevicaudatan clam shrimp with asymmetrically modified thoracopods from Yunnan, China (Crustacea: Branchiopoda). Zool Stud 58:28. doi:10.6620/ZS.2019.58-28. BACKGROUND Most metazoans are fundamentally bilaterally symmetrical, although many taxa display wellknown examples of the opposite condition, such as the assymmetrical arrangement of internal organs in vertebrates, or the shell coiling of gastropod mollusks. Within Crustacea the unequal chelae in decapod crabs (Palmer 1996) are classical examples of assymmetry, but also within Laevicaudata (Branchiopoda) assymmetry is seen; most well-documented is its presence in Paralimnetis, Lynceiopsis, Lynceus gracilicornis (Packard, 1871), and L. aequatorialis Daday, 1927, where male claspers and thoracopods II show clear differences between left and right sides (Martin and Belk 1988). The smooth clam shrimps, Laevicaudata Linder, 1945, are a small, monophyletic group of branchiopod Zoological Studies 58: 28 (2019) doi:10.6620/ZS.2019.58-28 1 © 2019 Academia Sinica, Taiwan crustaceans, sister to the Onychocaudata (Olesen 1998; Richter et al. 2007; Richter and Olesen 2013; Rogers and Olesen 2016; Schwentner et al. 2018). Laevicaudatan diversity was first reviewed by Daday (1913 1927), and Brtek (1997 2002), and most recently by Rogers and Olesen (2016) who provided an updated diagnosis and discussed synapomorphies. The diversity of Asian Laevicaudata was reviewed by Rogers et al. (2016), who recognised seven distinct species and one species complex. Lynceus simiaefacies Harding, 1941 is only known from Yemen. Lynceus planifascius Rogers et al., 2016 and L. spinimanus Rogers et al., 2016 occur in Thailand. Lynceus indicus Daday, 1927 and the L. denticulatus species complex occur in India and Sri Lanka. Lynceus mandsuricus Daday, 1927 and L. biformis (Ishikawa, 1895) are reported from northern China, Japan, and Korea (Rogers et al. 2016; Rogers and Olesen 2016). Here, we supplement the knowledge of bilaterally assymmetry in Laevicaudata by describing a new species of Lynceus (Branchiopoda: Laevicaudata) from Yunnan Province, China, characterised by uniquely modified and asymmetrical thoracopods III–IV. MATERIALS AND METHODS Specimens were collected in the field using a handheld dip net, and were preserved in 95% alcohol. Specimens were examined under a stereo microscope (Zeiss Stemi 508) and a compound microscope (Olympus CX31) in the laboratory. All drawings were made using a camera lucida, and light microscope images were taken with a ToupCam microscope digital camera on a compound microscope. Specimens were also photographed with an Olympus DP73 camera mounted on an Olympus SZX10 dissecting microscope and operated by Olympus CellSens microscope imaging software. Images were stacked using Zerene Stacker 1.04 (Zerene Systems LLC). A male and a female were prepared for SEM (Sigvardt et al. 2017) and examined with a JEOL JSM-6335-F (FE) housed at the Natural History Museum of Denmark, Copenhagen. Images were processed digitally with Photoshop CS and Corel PHOTO-PAINT X7 (Corel Corporation). Terminology follows Rogers and Olesen (2016), Olesen et al. (2016), and Sigvardt and Olesen (2014). Examined specimens are deposited in the following institutions: Kunming Natural History Museum of Zoology, Kunming Institute of Zoology (KIZ), Chinese Academy of Sciences; Natural History Museum of Denmark (NHMD); and the Applied Taxonomic Research Center, Khon Kaen University, Thailand (KKU). Comparative material Comparisons were made with Lynceus species from Asia and other continents, both from the literature and by direct examination of the material below. Acronyms: BMNH = British Museum (Natural History), London, United Kingdom; DCR = collection of D. Christopher Rogers; MNHB = Museum für Naturkunde – Leibniz Institut für Evolutionsund Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Germany; MNHN = Muséum national d’Histoire naturelle, Paris, France; NHMD = Natural History Museum of Denmark, Copenhagen, Denmark; USNM = US Natural History Museum, Washington D.C., USA; ZMUC = Zoological Museum, University of Copenhagen, old catalogue numbers at NHMD). Lynceus aequatorialis Daday, 1927. VENEZUELA: Apure state: Arichuna Road. Date unknown, G. Pereira. Id. D. Belk. Belk Collection; ~90 specimens, mostly females (USNM 1143987). Apure State: between Rio Apure and Rio Arauca. October 1894, F. Geay; 11 males, 4 females (MNHNIU-2007-764). Apure state: Guanaparo: 1899, F. Geay, Dad. Auct.; 13 males, 11 females (MNHNIU-2007-763). Apure state: Guanaparo: 1899. F. Geay, Dad. Auct.; 2 males, 2 females (MNHN-IU-2007-766). Lynceus biformis (Ishikawa, 1895). JAPAN: Shiga-Ken: Kusatsu-Shi: Kataoka-Cho. 26 May 2004, M.J. Grygier; 5 males (NHMD-615848, additional material: DCR-611). Shiga: Livsatsu: Kataoka-Cho: Rice paddies. 21 May 2001, M.J. Grygier; 16 males, 3 females (NHMD-81868/ZMUC-CRU-4020). TanoHanakuma: Takatsuki City: Osaka Prefecture, irrigated paddy field, 34°57'18.4"N, 135°35'23.7"E. 31 May 2018, S. Ishida; 2 males, 3 females (NHMD-615843). TAIWAN: Taipei: Yangminshan National Park. 2015, C.C. Wang; 1 male, 4 females (NHMD-615844). Lynceus brachyurus Müller, 1776. DENMARK: Klampenborg: Deer Garden: pond close to “Trepilelågen”. 28 April 2017, J. Olesen; 1 male, 4 females (NHMD-232312). USA: California: Sacramento County: Sloughhouse. 1 April 2008. D.C. Rogers; 8 males, 14 females (NHMD-265530, additional material: DCR-696). California: San Joaquin County: Large vernal pool south of Buena Vista Road. 14 February 1997, D.C. Rogers; 2 males, 3 females (NHMD-265529, additional material: DCR-103). Montana: Deer Lodge County: Pinter Lake pool. 23 July 1995, D.L. Gustafson, det. D.C. Rogers; 2 males, 1 female (NHMD-265531, additional material: DCR-574). Lynceus indicus Daday, 1927. INDIA: Bhowali Bazar: Kumaon. Year and collector unknown; 1 male, 3 females (MNHB 18 363). Lynceus planifascius Rogers, Saengphan, page 2 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Thaimuangphol and Sanoamuang, 2016. THAILAND: Khon Kaen Province: south of Don Han: roadside ditch on northeast side of Highway 208 flooded by rainwater, 16°18'45.88"N, 102°52'31.37"E. 19 June 2015, D.C. Rogers and L. Sanoamuang; 12 males, 44 females, topotypes (NHMD-615849, additional material: DCR889). Khon Kaen Province: south of Don Han: rice paddies on southwest side of Highway 208 flooded by rainwater, 16°19'18.08"N, 102°51'44.63"E. 19 June 2015, D.C. Rogers and P. Dabseepai; 10 males, 11 females (NHMD-615850, DCR-891). Udon Thani Province: table drain on Highway 2 (Mittraphap Road), south of Rual Road 100, 17°07'27.48"N, 102°58'25.22"E, 20 June 2015, D.C. Rogers and P. Dabseepai; 12 males,14 females (NHMD-615851, additional material: DCR-898). Lynceus simiaefacies Harding, 1941. YEMEN: Jebel Jihaf: Aden: 7100 ft. 1 September 1937, E. B. Britton; 1 male in ethanol (BMNH 1948.9.28.1), male and female thoracopods on 3 slides, paratypes (BMNH1940.7.23.1, 1940.7.23.2 and 1940.7.23.3). Lynceus spinimanus Rogers, Saengphan, Thaimuangphol, and Sanoamuang, 2016. THAILAND: Suphan Buri: Donchedi District: between Thap Luang and Sra Krachom, roadside ditch flooded by rainwater, 14°40'N, 99°50'E. 12 May 2012, N. Saengphan; holotype female (NHMD-86057/ZMUC-CRU-8213), allotype male NHMD-82062/ZMUC-CRU-8218), 2 paratype females (NHMD-86114/ZMUC-CRU-8270), respectively. RESULTS TAXONOMY Suborder Laevicaudata Linder, 1945 Family Lynceidae Baird, 1845 Genus Lynceus Müller, 1776 (Sensu Rogers and Olesen, 2016) Lynceus amplopedia sp. nov. (Figs. 1–8) urn:lsid:zoobank.org:act:B7291C7F-C41E-4310-9812D8F4A9409094 Type locality: CHINA: Yunnan Province: Qiubei County: Tianxing Township: Longtao Village: Shuiyantang temporary pond, near Road No. S206; 23°55'36.13"N, 104°14'17.04"E, altitude 1553 m asl. Type material: Holotype, male (KIZ-2015010). Allotype, female (KIZ-2015011). Paratypes: five males and five females (KKU-CS2015001), two males and two females, (NHMD-615845), 18 males and 23 females (KIZ-2015012-50). All collected 5 October 2015, by H. F. Yang from the type locality. Etymology: The specific epithet amplopedia is a combination of the Latin “amplus”, meaning “wide”, and the Latin “ped”, meaning “foot”. It refers to the unique, explanate modifications of endites 4 and 5 in male thoracopods III and IV. The gender is feminine. Specific Diagnosis: Both sexes: Rostrum bicarinate. Head in lateral view with anterior margin sinuate, compound eyes on an ocular tubercle and frontal setal fields in deep concavity (Figs. 1, 3, 5, 7, 8). Male: Left and right thoracopods asymmetrically modified. One side, termed ‘explanate modified side’ (usually left side, occasionally right), with endites 4, 5, and endopod explanate (thoracopods III and IV); exopod with 14–15 digitiform processes dorsomedially (thoracopods V and VI); broad muscular basis (thoracopods III–V). Opposite side, termed ‘spinose modified side’ (usually right side, occasionally left), with endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI) broad muscular basis (thoracopod V). Clasper palm with two scale patches (one laterally, one posteriorly), clasper endopod (movable finger) with constriction near articulation, endite 5 (large palp) dorsoventrally flattened with dorsal sulcus bearing setae (Figs. 1–6). Female: Rostrum distal margin broadly rounded and smooth, lacking serrations or lateral spines. Lamina abdominalis with four dorsal extensions and three marginal extensions (Figs. 1, 7, 8). Description: Male: Length range: 5.9–6.8 mm (Figs. 1A, 3A, B). Head (Figs. 1B, 3B, E, 5C) ~0.50 of body length. Occipital condyle round. Head anterior margin sinuate in lateral view, with three protrusions along rostrum: dorsal most the ocular tubercle, the second just distad to the setal fields (setal fields in deep concavity), and distal most approximately mid-length of rostrum. Dorsal organ oval, elongate, near occipital condyle. Compound eye sub-circular. Setal fields smaller than compound eyes, circular, with short dense setae, separated by rostral carinae proximal ends (Figs. 1B, C, 3D, 5A). Rostrum (Figs. 1C, 3D, 5A, B) with two medial carinae, extending distally from near setal fields. Carinae parallel in proximal third, diverging approximately 20° at distal two thirds, terminating before rostral apex. Rostrum truncate with acute apicolateral corners. Truncated rostral distal margin shallowly, evenly concave, with dense row of setae, denticles absent (Figs. 5A, B, D). Rostral apex in lateral view dorsoventrally flattened distally (Figs. 1B, 5D). Rostrum in anterior view broadest at apicolateral corners with constriction approximately 50% of rostral length. Rostrum greatest page 3 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Fig. 1. Lynceus amplopedia sp. nov., A–G: male: A, carapace, left lateral view; B, head, left lateral view; C, head, anterior view; D, right clasper, anterior view; E, left clasper, posterior view; F, opercular lamella, ventral view; G, telson, left lateral view. H–K: female: H, head, left lateral view; I, head, anterior view; J, carapace, left lateral view; K, lamina abdominalis, left lateral view. Scale bar = 1 mm. page 4 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Fig. 2. Asymmetry and modified thoracopods III–VI of Lynceus amplopedia sp. nov., setae and spines are presented only on endites 4, 5 and endopod. Abbreviations: e1–e5 = endites 1–5. page 5 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Fig. 3. Lynceus amplopedia sp. nov., male, stereo microscopy (paratype NHMD-615845). A, right lateral view (carapace valves removed); B, left lateral view (left carapace valve removed); C, dorsal view (head removed); D, ventral view; E, rostrum and claspers, ventrolateral view; F, left clasper, anterior view; G, carapace, right valve, exterior; H, left clasper, posterior view. Abbreviations: e1–e5 = endites 1–5, T3–T5 = thoracopods III–V. page 6 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Fig. 4. Lynceus amplopedia sp. nov., modified male thoracopods, light microscopy. Endites 3–5, and endopod of thoracopods I–VI and exopod of thoracopods V and VI. Explanate modified thoracopods (ET): thoracopod III with explanate endites 4 and 5, thoracopod IV with explanate endites 4, 5 and endopod, and thoracopods V and VI with exopods with digitiform processes. Spinose modified thoracopods (ST): thoracopod V with spinose endite 4 and thoracopod VI with spinose endites 3 and 4. Abbreviations: ET1–ET6 = explanate modified thoracopods 1–6; e3–e5 = endites 3–5. ST5,6 = spinose modified thoracopods V and VI. page 7 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan width 1.2x rostral length. Fornices extending from second antenna insertion to apicolateral corners (Figs. 1B, 3A, 3B). First antenna (Fig. 5F) with two antennomeres. Proximal antennomere cylindrical, length 2x breadth. Distal antennomere cylindrical, narrower than proximal antennomere, length 5.5x breadth, with two longitudinal rows of short sensory setae (or olfactory papillae). Second antenna (Fig. 5C) biramous, long, extending to thoracopod VIII. Peduncle coxa cylindrical and thick, with longitudinal row of 8–10 long plumose setae on posterior margin. Peduncle basis with two groups of short, acute setae on anterior margin: two setae at middle ventral margin and six setae distally at exopod base. Exopod (anterior flagellum) with approximately 29 flagellomeres, each bearing a posterior long, distally directed, plumose seta and a short, acute, anterior seta present in most flagellomeres (absent in distal two flagellomeres and eight setae on proximal flagellomere anterior margin). Endopod (posterior flagellum) with approximately 34 flagellomeres, each bearing posterior, distally plumose seta (as exopod). Flagellomere setal length about half of corresponding flagellum. Labrum large, lobiform, apex flat with fine setae. Mandible (Fig. 5E) broad, molar surface with 13 or 14 transverse bispinose ridges with moderate indentation between spines. Posteriormost four ridges larger, with last three more broadly spaced than remaining ridges, posterior most ridge projecting as spine. Anterior most ridges smaller with spines, cluster of setae anteriorly. Maxilla I (Fig. 5C) typical for genus, semicircular, with 11 plumose setae at medial margin, with three short denticles, robust setae at distal end, but lacking terminal setae of spines, posterior margin with fine setae. Maxilla II absent. Carapace (Figs. 1A, 3G) semitransparent, relatively thin, smooth (lacking growth lines), globose and suboval in lateral view. Length < width, broadest near adductor muscle attachment site. Carapace with a slightly depressed region at end of posterior hinge line. Carapace average dimensions: height 6.9 mm, length 7.5 mm, width 4.5 mm (n = 10). Thoracopods, 10 pairs, first pair modified as claspers (Figs. 1D, E, 5H–N). Thoracopods III–VI not bilaterally symmetrical (Figs. 2, 3C, 4, 6). The modifications of one side are here termed “explanate modifications” due to the explanate shape of certain endites and the endopod (see below). The modifications of the opposing side thoracopods are here termed “spinose modifications” due to presence of greatly specialized spines on endite 4 (see below). In ~86% of specimens (19 of 22 specimens) the explanate modifications are on the left side thoracopods and the spinose modifications on the right side; in the remaining ~14% the pattern is opposite (n = 3 of 22 specimens, see below). Thoracopod I (Figs. 1D, E, 3F, H, 5H–N) right and left clasper equal in size and shape. Endite 1 lobiform, elongate, margin with short setae and three pectinate spines. Endite 2 broadly transverse, margined with three setal types, (1) distal margin with ~50 long setae, each bearing dense, short setulae in distal half; (2) anterior surface submargin with ~40 short, smooth setae; (3) posterior surface submargin with ~20 long setae, each bearing sparse, long setulae in distal half. Endite 2 distal tenth slightly expanded, with six stout, long setae. Endite 3 (palm with gripping area) broadly transverse (Fig. 5K), length 1.5x width. Corm area 3 and 5 (sensu Kaji et al. 2014) covered with scales (Fig. 5I, M, N), medial margin with fine, type V setae (clasper setae types sensu Sigvardt and Olesen 2014). Gripping area with diverse setation: anterior margin with ~40 type IV setae (Figs. 1D, 5H), posterior margin with a row of ~seven long type I setae, a row of ~eight stout type II setae, and a group of six to eight type III setae (Figs. 1E, 5I–K, N). Endite 4 (small palp) digitiform, proximally expanded, length ~3x width, apex round, margined with ~15 long setae, endite 4 distal surface with four long setae, each bearing sparse, long setulae (Figs. 1E, 5I). Endite 5 (large palp) clavate, longer ~2x than endite 4, dorsoventrally flattened, proximal fifth arcuate, apex round, bearing ~20 simple setae; dorsal surface with sulcus with ~10–12 simple setae (Fig. 5L). Endopod (movable finger) digitiform, proximal fourth arcuate, diameter narrowing proximally distal to point of articulation, with sides diverging distally before apex (Figs. 1D, E, 5H, K). Endopod apex subacute, extending to one half of endite 3 medial surface. Clasper exopod elongate with setae along margin, mid-dorsal margin with three or four short, robust, spiniform setae, each with distal half bearing two rows of small denticles. Thoracopod II not modified, endites 4 and 5 slightly expanded distally, digitiform. Explanate modified side (holotype left side) (Figs. 2: ET3-ET6, 6A–C): Thoracopods III–V with greatly inflated, chitinous muscular bases. Thoracopod III endites 4 and 5 explanate; endite 4 length ~1.3x width, medial margin with sparse, long setae and apex with group of short setae; endite 5 length ~2x width, setae similar to endite 4 but apex with longer setae. Thoracopod IV endites 4, 5 and endopod explanate; endite 4 smaller than preceding endite 4, medial margin with long setae; endite 5 broadly ovate, medial margin with stout setae, apex with long setae; endopod subquadrate, medial margin with 12 stout setae and distally with four long, robust setae (Figs. 2, 6B). page 8 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Fig. 5. Lynceus amplopedia sp. nov., male, scanning electron microscopy (paratype NMHD-615845). A, head, anterior view (left antenna removed); B, head, anteroventral view, left antenna removed; C, head, right lateral view; D, rostral apex, left lateral view; E, left mandible, lateral view; F, left first antennae; G, telson with opercular lamella, ventral view. H, right clasper, anterior view; I, left clasper, posterior view, encircled areas with scales; J, setae (magnification of I); K, clasper gripping area with setae, apical view; L, large palp (e5), right clasper, dorsal view; M, clasper palm (e3) with scales (upper encircled area in I), lateral view; N, setae and scales of clasper gripping area (magnification of I). Abbreviations: e3–e5 = endites 3–5. page 9 of 16Zoological Studies 58: 28 (2019) © 2019 Academia Sinica, Taiwan Muz Prir vedy 48:49–59. Daday de Deés E. 1913. Magarorszag Kagylos levellabu rakjai (Phyllopoda, Conchostraca Hungariae). Magyar Tudomanyos Akademia Matematikai Termeszettudomanyi Osztalyanak Kozlemenyei 32:49–145. Daday de Deés E. 1927. Monographie systématique de Phyllopodes Conchostracés. III. Lynceidae. Annales des Sciences Naturelles (Paris), Zoologie (9ème sér.), pp. 1–112. Dai AY. 1982. Overview of Division Eubranchiopoda. In: Dong LM, Dai AY, Jiang XZ, Chen SZ, Chen YS and Cai RX (Eds) Atlas of Chinese Fauna, Crustacean, No. 1. Science Press, Beijing, China, pp. 5–13. Ferrari FD, Grygier MJ. 2012. Variability of trunk limbs along the anterior/posterior body axis of juvenile and adult Lynceus biformis (Ishikawa, 1895) (Branchiopoda, Laevicaudata, Lynceidae). Crustaceana 85:359–377. doi:10.1163/156854012x624655. Gauthier H. 1936. Entomostracés de Madagascar (5° note) Description d’un nouveau Lynceus (Conchostraces). Bull Soc Zool France 61:105–116. Han MS, Shu YF, Liu ZS. 1995. Benthic Crustacean. In: Han MS, Shu YF (Eds) Atlas of freshwater biota in China. Ocean Press, Beijing, China, pp. 296–305. Harding JP. 1941. Crustacea: Anostraca and Conchostraca. – British Museum (Natural History) Expedition to South-West Arabia, 1937–8, pp. 152–156. Hu WX. 1988. Studies of clam shrimps (Crustacea: Conchostraca)- II. Sixteen species of Conchostraca in China. Journal of Ocean University of Qingdao 18(2):66–86. Ishikawa C. 1895. Phyllopod Crustacea of Japan. Zoological Magazine 12(75):1–5. Kaji T, Fritsch M, Schwentner M, Olesen J, Richter S. 2014. Male claspers in clam chrimps (Crustacea, Branchiopoda) in the light of evolution: A case study on homology versus analogy. J Exp Zool B Mol Dev Evol 322(5):269–280. doi:10.1002/jez.b.22574. Linder F. 1945. Affinities within the Branchiopoda with notes on some dubious fossils. Ark Zool 37:1–28. Martin JW, Belk D. 1988. Review of the clam shrimp family Lynceidae Stebbing, 1902 (Branchiopoda: Conchostraca), in the Americas. J Crustacean Biol 8:451–482. doi:10.1163/ 193724088x00314. Martin JW, Felgenhauer BE, Abele LG. 1986. Redescription of the clam shrimp Lynceus gracilicornis (Packard) (Branchiopoda, Conchostraca, Lynceidae) from Florida, with notes on its biology. Zool Scr 15:221–232 Olesen J. 1998. A phylogenetic analysis of the Conchostraca and Cladocera (Crustacea, Branchiopoda, Diplostraca). Zool J Linn Soc 122:491–536. doi:10.1111/j.1096-3642.1998.tb02161.x. Olesen J, Richter S. 2013. Onychocaudata (Branchiopoda: Diplostraca), a new high-level taxon in branchiopod systematics. J Crustacean Biol 33:62–65. doi:10.1163/1937240x-00002121. Olesen J, Pöllabauer C, Sigvardt ZMS, Rogers DC. 2016. A New Species of Lynceus Müller, 1776 from New Caledonia (Crustacea: Branchiopoda: Laevicaudata) from dolines, with remarks on zoogeography. Eur J Taxon 224:1–18. Palmer AR. 1996. From symmetry to asymmetry: phylogenetic patterns of asymmetry variation in animals and their evolutionary significance. Proc Natl Acad Sci USA 93:14279–14286. doi:10.1073/pnas.93.25.14279. Palmer AR. 2004. Symmetry breaking and the evolution of development. Science 306:828–833. doi:10.1126/ science.1103707. Richter S, Olesen J, Wheeler WC. 2007. Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci. Cladistics 23:301–336. doi:10.1111/ j.1096-0031.2007.00148.x. Rogers DC, Olesen J. 2016. Laevicaudata Catalogus (Crustacea: Branchiopoda): An overview of diversity and terminology. Arthropod Syst Phylo 74(3):221–240. Rogers DC, Padhye S. 2015. Review of the large branchiopod crustacean fauna of the Indian subcontinent (Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cyclestherida). J Crustacean Biol 35(3):392–406. doi:10.1163/1937240x-00002327. Rogers DC, Saengphan N, Thaimuangphol W, Sanoamuang L. 2016. The lynceid clam shrimps (Branchiopoda: Laevicaudata) of Thailand, with keys to the Eurasian Species. J Crustacean Biol 36(3):384–392. doi:10.1163/1937240x-00002426. Rogers DC, Thaimuangphol W, Saengphan N, Sanoamuang L. 2013. Current knowledge of the Southeast Asian large branchiopod Crustacea (Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cyclestherida). Proceedings of the Freshwater Invertebrates of Southeast Asia Conference. J Limnol 72:69–80. doi:10.4081/ jlimnol.2013.s2.e5. Sanoamuang L, Murugan G, Weekers PHH, Dumont HJ. 2000. Streptocephalus sirindhornae, new species of freshwater fairy shrimp (Anostraca) from Thailand. J Crustacean Biol 20:559– 565. doi:10.1163/20021975-99990073. Schwentner M, Richter S, Rogers D, Giribet G. 2018. Tetraconatan phylogeny with special focus on Malacostraca and Branchiopoda: highlighting the strength of taxon-specific matrices in phylogenomics. Proc R Soc Lond Ser B Biol Sci 285:1–10. doi:10.1098/rspb.2018.1524. Shu SS, Rogers DC, Chen XY, Yang JX. 2015. Two new species of clam shrimp (Branchiopoda: Spinicaudata) from Yunnan Province, China. J Crustacean Biol 35:454–460. doi:10.1163/1937240x-00002338. Sigvardt ZMS, Olesen J. 2014. Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda) and functional morphology of male claspers in a phylogenetic context: A videobased analysis. PLoS ONE 91:e84021. doi:10.1371/journal. pone.0084021. Sigvardt ZMS, Rogers DC, Olesen J. 2017. Functional morphology of amplexus (clasping) in spinicaudatan clam shrimps (Crustacea, Branchiopoda) and its evolution in bivalved branchiopods: A video-based analysis. J Morphol 278:523–546. doi:10.1002/ jmor.20649. Sigvardt ZMS, Rogers DC, de los Ríos P, Palero F, Olesen J. 2019. First molecular phylogeny of Laevicaudata (Crustacea, Branchipoda) with description of a new species of Lynceus from Chile and an updated key to species in the Americas. Invertebr Syst 33:597-617. doi:10.1071/IS18073. Uéno M. 1940. Phyllopoda of Manchoukuo. In: Kwantung Ministry of Civil (Eds) Reports of Limnology Survey in Kwantung & Manchoukuo, Dairen. Kwantung, pp. 368–381. Vekhov NV. 1993. The fauna and zoogeography of fairy and tadpole shrimps of Russia and adjacent lands (Crustacea Anostraca, Notostraca). Arthropoda Sel 2:11–42. Yoon SM, Kim W. 2000. Taxonomic review on east Asian lynceid conchostracans (Crustacea, Branchiopoda, Laevicaudata) with redescription of Lynceus biformis of Korea. Korean J Biol Sci 4:123–129. doi:10.1080/12265071.2000.9647535. page 16 of 16Zoological Studies 58: 28 (2019)