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Holbrookia lacerata Cope 1880 Plateau Spot-tailed Earless Lizard (Fig. 8) Holbrookia maculata lacerata Stejneger 1890 Holbrookia lacerata lacerata Axtell 1956 Lectotype. U. S. National Museum (USNM 10160 A); collected by G.W. Marnock in May 1879 within a 3 mile radius circle around Helotes, Bexar County, Texas, USA (29�� 35��� N; 98�� 41��� W). Etymology. Holbrookia is derived from the last name of the American zoologist John Edwards Holbrook. Lacerata is derived from the latin word lacerare, which means to cut, destroy, or mangle. Cope (1880) described the posterior border of the transverse brown bars on the dorsum as serrate or digitate. This feature likely brought about the name lacerata. Distribution: Holbrookia lacerata includes all populations north of the Balcones Escarpment in Texas. This distribution extends north to the Colorado River, east to the eastern edge of the Balcones Escarpment and west to the Pecos River and southern edge of the Llano Estacado. Diagnosis. Morphological description based on measurements and counts from 112 adults. This is a small, earless lizard with an average of 4 (0 ��� 10) black spots on the underside of the tail. The average snout-vent length (SVL) is 54 mm (32 ��� 63), paravertebral and dorsolateral body blotches are often fused. An average of 2 (0 ��� 6) blotches are fused out of an average of 6 (4 ��� 9) blotches. The blotches form two rows of transverse bands with the dorsal edges of the bands usually narrowing and extending anteriorly. The dark blotches on the hind legs usually form distinct bands with the average number of leg bands and blotches being 7 (4 ��� 11). Some individuals have black lateral spots on the abdomen and these average 0.4 (0 ��� 4). The average number of femoral pores on the left leg is 13 (10 ��� 17). Females and some males develop a red-orange pattern on their throat and neck during the breeding season., Published as part of Hibbitts, Toby J., Ryberg, Wade A., Harvey, Johanna A., Voelker, Gary, Lawing, A. Michelle, Adams, Connor S., Neuharth, Dalton B., Dittmer, Drew E., Duran, C. Michael, Wolaver, Brad D., Pierre, Jon Paul, Labay, Benjamin J. & Laduc, Travis J., 2019, Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?, pp. 139-154 in Zootaxa 4619 (1) on page 147, DOI: 10.11646/zootaxa.4619.1.6, http://zenodo.org/record/3248485, {"references":["Cope, E. D. (1880) On the zoological position of Texas. Bulletin of the U. S. National Museum, 17, 1 - 51. https: // doi. org / 10.5479 / si. 03629236.17","Stejneger, L. (1890) Part V. - Annotated list of reptiles and batrachians collected by Dr. C. Hart Merriam and Vernon Bailey on the San Francisco Mountain Plateau and desert of the Little Colorado, Arizona, with descriptions of new species. North American Fauna, 103 - 118. https: // doi. org / 10.3996 / nafa. 3.0006","Axtell, R. A. (1956) A solution to the long neglected Holbrookia lacerata problem and the destription of two new subspecies of Holbrookia. Bulletin of the Chicago Academy of Science, 10 (11), 163 - 179."]} more...

Holbrookia subcaudalis (Axtell 1956) Tamaulipan Spot-tailed Earless Lizard (Fig. 9) Holbrookia lacerata subcaudalis Axtell 1956 Holbrookia subcaudalis Hibbitts et al. 2019 (this study) Holotype. Texas Natural History Collection, University of Texas (TNHC 20000); collected by Ralph W. Axtell on 6 June 1955 in plowed field 4.8 miles east northeast of Bishop, Nueces County, Texas, USA (27�� 36��� N; 97�� 45��� W) at an elevation of 75 feet. Etymology. The name subcaudalis is derived from the latin word sub which means under or below and cauda which means tail. This refers to the dark spots on the underside of the tail in this species. Distribution. Holbrookia subcaudalis is composed of all populations south of the Balcones Escarpment in Texas and west to the Sierra Madre Oriental in Coahuila, Nuevo Leon, and Tamaulipas, Mexico. They are absent from areas with sandy soils. Diagnosis. Morphological description based on measurements and counts from 45 adults. This is a small, earless lizard with an average of 5 (1 ��� 10) black spots on the underside of the tail. The average snout-vent length (SVL) is 56 mm (31 ��� 72), paravertebral and dorsolateral body blotches are often separated. An average of 0.7 (0 ��� 6) blotches are fused out of an average of 6 (4 ��� 9) blotches. The blotches form four rows of transverse mostly circular blotches. The dark blotches on the rear legs are circular in shape and do not form into bands with the average number of leg blotches being 8 (4 ��� 14). Most individuals have black lateral spots on the abdomen and these average 2.6 (0 ��� 5). The average number of femoral pores on the left leg is 14 (10 ��� 19). The female body color is greenish yellow during the breeding season but they do not acquire orange on the throat in either sex., Published as part of Hibbitts, Toby J., Ryberg, Wade A., Harvey, Johanna A., Voelker, Gary, Lawing, A. Michelle, Adams, Connor S., Neuharth, Dalton B., Dittmer, Drew E., Duran, C. Michael, Wolaver, Brad D., Pierre, Jon Paul, Labay, Benjamin J. & Laduc, Travis J., 2019, Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?, pp. 139-154 in Zootaxa 4619 (1) on pages 148-149, DOI: 10.11646/zootaxa.4619.1.6, http://zenodo.org/record/3248485, {"references":["Axtell, R. A. (1956) A solution to the long neglected Holbrookia lacerata problem and the destription of two new subspecies of Holbrookia. Bulletin of the Chicago Academy of Science, 10 (11), 163 - 179."]} more...

Key to the species groups of Psilorhynchus 1 a. Branched dorsal-fin rays 8.............................................................................. 2 1 b. Branched dorsal-fin rays 9���10.......................................................................... 3 2 a. Lateral line scales 33���36; unbranched pectoral-fin rays 4���5............................................. P. sucatio 2 b. Lateral line scales 39���48; unbranched pectoral-fin rays 7���11............................ P. homaloptera species group 3 a. Caudal fin forked, lobes weakly rounded or pointed; scales along dorsal body surface with dark posterior edge, forming strong reticulate pattern; scales in lateral-line scale row (L 1) and scales in two rows directly above (L+ 1 & 2) and one row below lateral line scale row (L- 1) marked posteriorly with a small spot, forming a series of rows (L rows) along body side; postepiphyseal fontanelle obvious, similar in size and shape to preepiphyseal fontanelle, separated by a narrow strut of frontal bone................................................................................ P. nudithoracicus species group 3 b. Caudal fin weakly forked, lobes rounded; dorsal body surface without strong reticulate pattern; scales in lateral line scale row and row directly above and below lateral line scale row without obvious spot along posterior edge (scales may be marked with a spot at center); postepiphyseal fontanelle, when visible, irregularly shaped, smaller than preepiphyseal fontanelle and separated by a large gap................................................................. P. balitora species group, Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on page 205, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175 more...

Psilorhynchus nudithoracicus Tilak & Husain Figs. 15���20 Psilorhynchus sucatio nudithoracicus Tilak & Husain, 1980: 35, figs. 1���3. Psilorhynchus gracilis Rainboth, 1983: 69, figs. 2���3. Material examined: 97 specimens, including holotype and 32 paratypes of P. gracilis. Ganges: AMNH 43097, 5 (1 c&s) paratypes of P. gracilis, 20.0��� 34.5 mm SL; ANSP 148729, 5 paratypes of P. gracilis, 28.1���37.1 mm SL; FMNH 94285, 5 paratypes of P. gracilis, 5, 30.5���38.1 mm SL; Bangladesh: Dinajpur, Mahananda River at Tetulia, in close vicinity of the Dak Bungalow, 26 �� 28 '60.0"N 88 �� 19 '60.0"E. KU 29143, 11 (3 c&s), 26.4���32.4 mm SL; Nepal: Jhapa, Mechi River at Bhadrapur, 26 �� 32 ' 17.9 "N 88 �� 6 ' 6.1 "E. KU 29461, 1, 35.0 mm SL; Nepal: Bardiya, Babai River at Chapang, 28 �� 21 ' 24.1 "N 81 �� 42 ' 47.9 "E. KU 29505, 1, 32.5 mm SL; Nepal: Nawalparasi, Tribeni, Narayani River, just downstream from Tribeni Barrage, 27 �� 26 ' 35.9 "N 83 �� 54 '18.0"E. KU 28815, 7, 23.2 ���27.0 mm SL; Nepal: Banke, Bhurigaon, Rapti River at Madhuwaa/Kanchanpur, 28 �� 4 '12.0"N 81 �� 50 ' 48.1 "E. KU 40285, 4, 15.2 ���38.0 mm SL; Nepal: Jhapa, Kankai River at Raj���Marg highway, 26 �� 39 ' 29.9 "N 87 �� 52 '12.0"E. KU 40662, 3, 44.6���46.9mm SL: Nepal: Narayani, Chitwan, tributary of the Rapti River, Chitwan National Park, 27 �� 34 ' 20.7 "N 84 �� 29 '47.0"E. UMMZ 205351, 15, 27.6���41.7 mm SL; Bangladesh: Dinajpur, Keratoya River at Bhajanpur, downstream from Indian border, 26 �� 28 '0.0"N 88 �� 28 '60.0"E. Brahmaputra: NRM 46908, 3, 26.1���45.6 mm SL; India: Assam, Sessa River close to Patiola Village, about 30 km SW of Dibrugarh, 27 �� 18 '47.0"N 94 �� 49 '46.0"E. UMMZ 205342, holotype of P. gracilis, 50.5 mm SL; UMMZ 205343, 26 (10 examined), paratypes of P. gracilis, 29.4���49.9 mm SL; Bangladesh: Rangpur, Jabuneswari River, downstream from Badarganj Ghat, 25 �� 42 ���0.0���N 89 �� 5 ��� 0.0E. UMMZ 205345, 5 (3 c&s) paratypes of P. gracilis, 34.5 ���40.0 mm SL; Bangladesh: Rangpur, Ghaghat River, 6.5 km E of Rangpur on Badargani Road, 25 �� 45 '0.0"N 89 �� 28 '60.0"E. UMMZ 205340, 18, 10.4 ���19.0 mm SL; Bangladesh: Rangpur, Dharla River at Kurigram, 400 m upstream from ferry ghat, 25 �� 47 '60.0"N 89 �� 40 '0.0"E. UMMZ 244920, 2, 49.0���50.0 mm SL; India: West Bengal, Panga River at Krishibagan, 26 �� 28 '22.0"N 88 �� 42 '8.0"E. Meghna: UF 180115, 5, 20.0���40.0 mm SL; Bangladesh: Dhaka. Sangu: UMMZ 205337, 2 paratypes of P. gracilis, 25.7���29.7 mm SL; Bangladesh: Chittagong, Chittagong Hill Tracts, Sangu River and small tributary creek ca. 2 km upstream from Bandarban, 22 �� 13 '0.0"N 92 �� 11 '60.0"E. Diagnosis. Psilorhynchus nudithoracicus is distinguished from all congeners by its large and flap-like skin folds at the lateral corner of the mouth, which extend further posteriorly than the lower jaw cushion and are covered in large ���head of cauliflower��� papillae (vs. skin folds not reaching past posteriormost part of lower jaw cushion, non-papilliated or with small dome-like papillae). It is further distinguished from members of the P. nudithoracicus species group by the following combination of characters: two dorsal saddles anterior to dorsal saddle positioned at dorsal-fin origin (vs. one); L+ 2 row present, composed of 5���10 obvious dark brown blotches (vs. L+ 2 composed of few indistinct blotches in P. robustus; absent in P. melissa and P. tenura); most commonly 17 + 17 vertebrae (vs. 18 + 16 in P. melissa and P. robustus; 18 + 18 in P. t e n u r a). It is further distinguished from P. melissa by having irregular dark brown or black markings on the dorsal fin (vs. dorsal fin marked with a dark brown or black band along distal edge), from P. robustus by having dorsal saddles posterior to the dorsal fin poorly developed (vs. dorsal saddles posterior to the dorsal fin well-developed), and by having the anteriormost lateral blotch equal in size or smaller than more posterior blotches (vs. anteriormost lateral blotch larger than more posterior blotches), and from P. tenura by a lower number of principal caudal-fin rays (9���10 + 9 vs. 9 + 8), a shorter caudal peduncle (caudal peduncle length 9���13 % SL vs. 14���16 % SL), the presence (vs. absence) of a short mandibular canal along the anguloarticular, and the presence (vs. absence) of L rows above and below the lateral line scale row. Description. General body shape as in Figures 15���17. Morphometric data are listed in Table 1 and select meristic characters in Tables 2 and 3. Body elongate, dorsal profile arched, rising moderately to dorsal-fin origin, sloping gently towards caudal peduncle. Body depth greatest at dorsal-fin origin, narrowest at base of caudal peduncle. Ventral profile moderately straight from lower jaw to anal-fin origin, weakly concave from anal-fin origin to caudal-fin base. Head and eye large, pupil round. Mouth inferior. Snout moderate, less than half of head length. Snout rounded anteriorly, its ventral surface bordered by a deep longitudinal groove on each side. Rostral cap and upper lip fused, separated by a shallow groove; posterolateralmost part of rostral cap continuous around corner of mouth, contacting with skin fold at posterolateral corner of mouth; posterior margin of rostral cap covered in low, cobblelike papillae (Fig. 19). Lower lip portion of lower-jaw cushion broadly rectangular, anterior edge weakly rounded; superficial layer of lower-jaw cushion covered in large, pillar-like globular papillae, separated by deep grooves; smaller globular papillae, continuous with large pillar-like globular papillae on superficial layer of lower-jaw cushion, present on skin surface along ventral midline posterior to lower-jaw cushion, becoming increasingly sparse towards isthmus. Upper lip covered with low triangular unculi, ranging in height from ~ 5���15 ��m; lower jaw unculi not examined. Skin fold around posterolateral corner of mouth large and flap-like, continuous anteriorly with posterolateralmost part of upper lip and rostral cap; outer edge of skin fold heavily papilliated with large cauliflower-like papillae; unculi and tubercles absent from surface of skin fold (Fig. 19). Posterior edge of rostral cap, lower lip, skin fold, and globular papillae all densely covered with tastebuds. Gill membranes joined to isthmus. Pre-epiphyseal and post-epiphyseal fontanelle long and rectangular, separated by a narrow strut of frontal, dorsal to the epiphyseal bar. Five infraorbitals (IO 1���5). IO 1���3 plate like, IO 1 largest of the series. IO 4���5 narrow tube-like bones, composed of sensory canal ossification only. Cephalic sensory system well developed. Openings in anguloarticular portion of preopercular mandibular canal 2. Openings in preopercular portion of preopercularmandibular canal 6. Openings in nasal portion of supraorbital canal 2 or 3. Parietal portion of supraorbital canal open. Openings in parietal portion of temporal canal 2. Fifth ceratobranchial with a single row of four needle-like teeth. Hyoid bar with three branchiostegal rays of similar length and shape. Basihyal short, spatula shaped. Anterior swimbladder chamber surrounded by a thick peritoneal tunic, partially enclosed in a bony capsule formed anteriorly by lateral process of 2 nd vertebral centrum and laterally by outer arm of os suspensorium. Posterior swimbladder chamber greatly reduced in size. Dorsal-fin rays iii. 9 (49) or iii. 10 (2). Anal-fin rays ii. 6 (44). Principal caudal-fin rays 9 + 9 (1), 10 + 8 (1) or 10 + 9 (39), dorsal procurrent rays 6 (2), 7 (3) or 8 (2), ventral procurrent rays 4 (1), 5 (4) or 6 (2). Pectoral fin rays iv. 10 (6), iv. 11 (11), iv. 12 (4), v. 10 (6), v. 11 (16) or v. 12 (3), pelvic fin rays ii. 7 (48) or ii. 8 (1). Paired fins horizontally placed, pectoral fins larger than pelvic fins. Pectoral fin not reaching vertical through dorsal-fin origin, reaching two to four scale rows anterior to pelvic-fin origin when adpressed. Pelvic-fin origin posterior to dorsalfin origin, insertion opposite second or third branched dorsal-fin ray. Well-developed unculiferous paired-fin pads present along ventral surface of four���five anteriormost pectoral-fin rays and two anteriormost pelvic-fin rays. Dorsal fin high, triangular in shape with weakly pointed tip; posterior margin weakly concave. Anal fin small, triangular in shape with weakly pointed tip; posterior margin weakly concave; not reaching caudal-fin base when adpressed. Caudal fin moderately forked, tips of upper and lower lobes weakly rounded. Scales cycloid, large, with 6���8 well-developed radii over posterior field of scale body. 32 (6), 33 (26) or 34 (7) scales along lateral line, plus 1 (10) or 2 (22) on base of caudal fin. 3.5 / 1 / 2 transverse scale rows from dorsal-fin origin to pelvic-fin origin, 10 around caudal peduncle, 10 (16), 11 (27) or 12 (1) predorsal scales, 8 (1), 9 (33), or 10 (10) scales between anus and anal-fin origin. Ventral surface between paired fins without scales. Total number of vertebrae 34, consisting of 17 + 17 (6) or 18 + 16 (1) abdominal and caudal vertebrae. Small conical tubercles with hard keratinized tip distributed over lateral, dorsal and ventral surfaces of head, including snout and anteroventral region of rostral cap. Tubercles present on posteroventral region of rostral cap dagger-like, larger than those on other surfaces of head. Head tuberculation more strongly developed in males. Tight elongate cluster of tubercles present on lateral surface of head below orbit in males only. Scales situated posterior to occiput along dorsal midline and dorsolateral body surface with three or four small elongate tubercles, forming small keels orientated along antero-posterior body axis, in males only. Anteriormost rays of pectoral fin with small conical tubercles, multiple rows thick, present along dorsal surface; tubercles largest along anteriormost ray, gradually decreasing in size on more posterior rays. Remaining fins without tubercles in males. All females examined lack tubercles on body and fins. Coloration. In alcohol body background color light cream (Fig. 15���17). Occiput dark brown. Dorsal surface between occiput and dorsal fin with three indistinct dark brown saddles, first situated anterior to midpoint between occiput and dorsal-fin origin, second situated at midpoint between first and third, third situated at dorsal-fin origin. Dorsal saddles posterior to dorsal-fin origin indistinct, numbering four or five; position variable except for first, situated below middle of dorsal fin, and last, situated at base of caudal fin. Dorsal saddles without contact to lateral blotches or lateral stripe, extending ventrally one (first four) or two (last four or five) scale rows on body side. Flank with 7 to 10 (typically 8) dark brown lateral blotches arranged in a longitudinal row. Size and position of lateral blotches along flank highly variable, excluding first, situated posterodorsal to opercular opening, and last, situated at caudal-fin base. Lateral stripe poorly developed. Scales situated over dorsal surface of body bordered posteriorly with dark brown pigment, forming distinct reticulate pattern over dorsal surface, strongest anterodorsally. Scales in lateral line scale row (L 1) with dark blotch posteriorly, punctuated centrally by unpigmented lateral line canal (giving appearance of double dash line along lateral line scale row). L+ 1, L+ 2 and L- 1 rows present in individuals over 30mm SL, length of rows increasing substantially with size. In large adult specimens (> 40 mm SL), L+ 1 row may extend along entire lateral side of body; L+ 2 shorter than L+ 1, restricted to middle of body, composed of 5���10 blotches; L- 1 row intermediate in length between L+ 1 and L+ 2, rarely extending posterior to anal-fin origin. Unscaled base of pectoral fin and scales adjacent to pelvic-fin origin peppered with small dark brown melanophores, forming indistinct pectoral-base and pre-pelvic spots, respectively. Lateral surface of snout, region rimming ventral margin of orbit and skin over opercle densely scattered with dark brown melanophores. Ventral surface largely devoid of pigment except for melanophores along anterior edge of rostral cap, small patch of brown melanophores situated beneath scales at anal-fin origin and a short line of melanophores posterior to anus, running along ventral midline from anus to 5 th scale in scale row running between anus and anal-fin origin. Dorsal surface of anterior pectoral- and pelvic-fin rays marked with small melanophores, number and intensity increasing substantially with size. Dorsal fin with irregular apical dark brown blotch, formed by melanophores centered around fork of first branched ray. Anal fin hyaline. Caudal fin pigmentation highly variable. Majority of specimens with dark brown blotch over base of central caudal-fin rays and two dark brown marking on upper and lower lobes. In several specimens markings along lower lobe and blotch at base of caudal fin are confluent (Fig. 17). Distribution and habitat. Psilorhynchus nudithoracicus is known from the Ganges River drainage in Bangladesh, India (West Bengal and Uttar Pradesh) and Nepal, the Brahmaputra River drainage in Bangladesh and India (Assam and West Bengal), and the Meghna and Sungu River drainages in Bangladesh and India (Rainboth, 1983; Rahman, 2005; Edds & Ng, 2007; Fig. 21). Tilak & Husain (1980) describe the type locality (Bamrauli Canal; Pilibhit District, Uttar Pradesh) as a slow moving stream with a sandy bed. Rainboth (1983) reports collecting P. nudithoracicus over small pebbles, in shallow running water, over a ���primarily sand��� substrate. Remarks. This species has been exclusively referred to as P. gracilis Rainboth, 1983 (e.g., Talwar & Jhingram, 1991; Menon, 1999; Conway & Kottelat, 2007; Edds & Ng, 2007; Conway, 2011). Rainboth (1983) described P. gracilis based on specimens obtained from Bangladesh, making explicit comparisons with P. balitora, P. homaloptera, P. pseudecheneis and P. sucatio (i.e., the four species of Psilorhynchus recognized as valid at that time). Rainboth (1983) also commented on other nominal forms of Psilorhynchus, including P. s. d a m o d a r a i, P. variegatus and P. h. ro w l e yi, but made no mention of P. s. nudithoracicus, suggesting that he was not aware of Tilak & Husain���s earlier work. Though we have not had the opportunity to examine the type material of P. s. nudithoracicus, critical examination of Tilak & Husain���s (1980) description, combined with observations we have made on numerous specimens referred to as P. gracilis from Nepal, India and Bangladesh (including type material), failed to identify any differences between P. gracilis and P. s. nudithoracicus. Specifically, the characters listed as diagnostic for P. gracilis by Rainboth (1983) do not suffice to distinguish this species from P. nudithoracicus. Both species have overlapping lateral line scale counts (34���36 listed by Tilak & Husain for P. s. nudithoracicus [presumably including those scales on base of caudal fin] vs. 33���36 [35���37 including scales on base of caudal fin] listed by Rainboth for P. gracilis), and identical numbers of unbranched pectoral-fin rays (4���5), lack scales on the midventral region between paired fins (see Fig. 2 in Tilak & Husain, 1980; Fig. 12 B), and exhibit two distinct spots along the dorsal midline between the occiput and dorsal-fin origin (see Fig. 1 in Tilak & Husain, 1980; Figs. 15��� 17). We conclude, based on the evidence in hand, that both names apply to the same species. Accordingly, we treat P. gracilis as a junior subjective synonym of P. nudithoracicus. Examination of the type material of P. nudithoracicus, deposited in the collections of the Northern Regional Station of the Zoological Survey of India in Dehra Dun (Tilak & Husain, 1980), will be an important next step to further test our conclusions. Psilorhynchus nudithoracicus, as understood herein, is a widespread species, occurring throughout much of the Ganges and Brahmaputra drainages in northeastern India and northwestern Bangladesh (Rainboth, 1983), the Ganges drainage throughout southern Nepal (Edds & Ng, 2007; T. K. Shrestha, 2008), and the Meghna and Sangu drainages in eastern Bangladesh (Rainboth, 1983). Most of our observations on this species are based on Gangetic material from southern Nepal and northwestern Bangladesh and we have examined relatively few specimens from the Brahmaputra drainage of northeastern India (5 specimens; 2 from West Bengal and 3 from Assam) or the Meghna (5) and Sangu (2) drainages of eastern Bangladesh. Surprisingly, Menon (1999) makes no mention of P. gracilis (sensu Rainboth, 1983) in his checklist of Indian freshwater fishes and the distribution of P. nudithoracicus throughout northeastern India is currently unclear and notably patchy (Fig. 21). In addition to Assam, Uttar Pradesh, and West Bengal, P. nudithoracicus has been reported from Manipur and Mizoram, by Vishwanath et al. (2007) and Kar & Sen (2007), respectively, based on material collected from the Barak River drainage. We have excluded the Manipur record of P. nudithoracicus from our distribution map because Vishwanath et al. (2007) did not provide precise locality information, but include the record provided by Kar & Sen (2007), based on specimens collected from the Tuirial River. We have also recently examined photographs of P. nudithoracicus from the Langkaih River, a tributary of the Tlawng River, in Mizoram. We have been unable to locate any records of P. nudithoracicus from the Indian states of Bihar, Meghalaya, or Tripura in the literature but suggest that it is likely to occur in these states, given its presence in neighboring states or countries. Tilak & Husain (1980) distinguished P. nudithoracicus from P. sucatio (in part), based on features of caudal-fin coloration, specifically a distinctive elongate black marking along the lower lobe of the caudal fin. We have observed such a marking only in relatively few individuals of P. nudithoracicus from southern Nepal (Fig. 17), but note that a similar marking is present in the specimen of P. nudithoracicus figured in Vishwanath et al. (2007; 91), the locality of which is unspecified. In the majority of specimens examined, the caudal fin is decorated with five dark brown/black blotches, with one located at the center of the caudal-fin base, and two on each lobe (Fig. 15, 16). There is also some variation in the extent of the L- 1 row, which is restricted to the center of the body in the majority of material examined (including the holotype of P. gracilis; Fig. 15) but extends almost along the entire length of the body in the larger specimens that we have examined from eastern Assam (NRM 46908; Fig. 16). This is also the case in the individual of P. nudithoracicus figured, Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on pages 223-230, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175, {"references":["Tilak, R. & Husain, A. (1980) Description of a new psilorhynchid, Psilorhynchus sucatio nudithoracicus (Psilorhynchidae: Cypriniformes) from Uttar Pradesh with notes on zoogeography. Mitteilungen aus dem Zoologischen Museum in Berlin, 56, 35 - 40.","Rainboth, W. J. (1983) Psilorhynchus gracilis, a new cyprinoid fish from the Gangetic lowlands. Proceedings of the California Academy of Sciences, 43, 67 - 76.","Rahman, A. K. A. (2005). Freshwater Fishes of Bangladesh. Second Edition. Zoological Society of Bangladesh, Dhaka, xviii + 394 pp.","Edds, D. R. & Ng, H. H. (2007) Additions to the ichthyofauna of Nepal, with a redescription of Neoeucirrhichthys maydelli (Teleostei: Cobitidae). Ichthyological Exploration of Freshwaters, 18, 125 - 132.","Talwar, P. K. & Jhingran, A. G. (1991) Inland Fishes of India and Adjacent Countries. Oxford and IBH Publishing Company, New Delhi, 2 vols., xvii + 1158 pp.","Conway, K. W. & Kottelat, M. (2007) A new species of Psilorhynchus (Teleostei: Psilorhynchidae) from the Ataran River drainage, Myanmar, with comments on the generic name Psilorhynchoides. Zootaxa, 1663, 47 - 57.","Shrestha, T. K. (2008) Ichthyology of Nepal: A Study of Fishes of the Himalayan Waters. Himalayan Ecosphere, Kathmandu, 388 pp.","Vishwanath, W., Lakra, W. S. & Sarkar, U. K. (2007) Fishes of North East India. National Bureau of Fish Genetic Resources, Lucknow, xxviii + 264 pp.","Kar, D. & Sen, N. (2007) Systematic list and distribution of fishes in Mizoram, Tripura and Barak drainage of northeastern India. Zoos' Print Journal, 22, 2599 - 2607.","Arunachalam, M., Muralidharan, M. & Sivakumar, P. (2007) Psilorhynchus amplicephalus, a new species from Balishwar river of Assam, India. Current Science, 92, 1352 - 1354.","Conway, K. W. & Mayden, R. L. (2008 b) Two new species of Psilorhynchus (Ostariophysi: Psilorhynchidae) with the redescription of P. balitora. Ichthyological Exploration of Freshwaters, 19, 215 - 232."]} more...

Psilorhynchus balitora species group Diagnosis. Members of this species group are distinguished from congeners by the following combination of characters: anteriormost branchiostegal ray greatly reduced, composed of articular head only, or absent; parietal portion of temporal sensory canal with three openings (only two openings present in available material of P. hamiltoni and P. pavimentatus); articular portion of preopercular-mandibular sensory canal absent; caudal fin weakly forked, with tips of upper and lower lobes rounded. Included species. P. balitora, P. brachyrhynchus, P. breviminor, P. hamiltoni, P. nepalensis, P. pavimentatus, and P. rahmani. Remarks. Conway (2011) originally diagnosed the P. balitora group based solely on two osteological characters (anteriormost branchiostegal ray greatly reduced, composed of articular head only, or absent, and postepiphysial fontanelle smaller than preepiphysial fontanelle). We continue to utilize the first of these characters here but no longer consider the second (size of the postepiphysial fontanelle in relation to the preepiphysial fontanelle) to be particularly useful given the size variation that exists in both of these structures across the members of this group (Fig. 13 F���L). Two additional osteological characters, both from the cephalic sensory canal system, appear also to be useful for recognizing members of this group, when utilized in combination with other characters, including: the absence of the anguloarticular portion of the preopercular-mandibular sensory canal and the presence of three openings in the parietal portion (Fig. 2, 13 F���I, K) of the temporal sensory canal (present in all members except for P. pavimentatus and P. hamiltoni; Fig. 13 J, L). The anguloarticular portion of the preopercularmandibular canal is also absent in P. sucatio, P. pseudecheneis and P. tenura but is invariably present in all remaining members of the P. nudithoracicus group. The third opening in the parietal portion of the temporal sensory canal in not found outside of the P. balitora species group. This opening is located close to the lateral edge of the parietal, on a small branch of the main channel. The surface pore associated with this opening could not be located in any alcohol specimens, suggesting that it may be relatively small. We follow Conway (2011) and tentatively consider P. amplicephalus, P. gokkyi and P. piperatus to belong to this group, pending further investigation., Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on page 231, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175 more...

Psilorhynchus nudithoracicus species group Diagnosis. Members of this species group are distinguished from congeners by the following combination of characters: pre- and postepiphysial fontanelle a long rectangular opening, similar in size and separated only by a narrow strut of frontal dorsal to the epiphysial bar; scales over anterodorsal body surface edged with dark brown pigment posteriorly, forming a strong reticulate pattern; scales in lateral line scale row (L 1) marked posteriorly with a small spot, often divided by unpigmented lateral line canal, forming a double-dash line along lateral line scale row; scales in two rows directly above (L+ 1 & 2) and one row below (L- 1) lateral line scale row marked posteriorly with a small blotch, forming a series of rows (L rows) of variable length along body side (absent in P. tenura); caudal fin moderately forked, with tips of upper and lower lobes weakly rounded. Included species. P. melissa, P. nudithoracicus, P. ro b u s t u s and P. t e n u r a. Remarks. This group is roughly equivalent to the P. gracilis species group proposed by Conway (2011), with the addition of P. t e n u r a. Several of the osteological characters listed as diagnostic for that group by Conway (2011), including the presence of a short mandibular sensory canal along the ventrolateral face of the anguloarticular, a prominent dorsal projection on the third pectoral radial, and a hiatus between the proximal tip of hypural one and the compound centrum define a more exclusive subgrouping of the P. nudithoracicus group (composed of P. melissa, P. nudithoracicus and P. robustus)., Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on page 223, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175 more...

Psilorhynchus sucatio (Hamilton) Figs. 2���9 Cyprinus sucatio Hamilton, 1822: 347, 393 [rivers of Northern Bengal; no types known]. Psilorhynchus sucatio var. damodarai David 1953: 248, fig. 2 [Type locality: 12 mi. below the confluence of the Barakar with the Damodar R., India; 15 syntypes?]. Material examined: 462 specimens. Ganges: AMNH 43096, 5 (2 c&s), 13.7���17.6 mm SL; ANSP 148728, 5, 14.0��� 18.8 mm SL; FMNH 94284, 5, 17.1 ���19.0 mm SL; USNM 231694, 5, 14.7���19.6 mm SL; Bangladesh: Dinajpur, Tangon River at Thakurgaon, 200 m upstream from bridge, 26 �� 1 '60.0"N 88 �� 25 '60.0"E. BMNH 1985.9.16.35���38, 4, 48.5���52.7 mm SL; Nepal: Chitwan National Park, Narayani River. CAS 50200, 23, 17.6���49.3 mm SL; Nepal: Chitwan Valley, including Khagari Khola, 72 km E of and slightly N of Hetauda and 18 km SSE of Narangar. CAS 50245, 2, 36.9, 42.0 mm SL; Nepal: Chitwan Valley, small streams rising in Churia Hills or ranges and flowing N into Rapti River. CAS 50289, 40 (8 c&s), 14.0��� 52.8 mm SL; Nepal: Chitwan Valley, Reu River near confluence with Rapti River. CAS 50316, 7, 41.0��� 57.1 mm SL; Nepal: Chitwan Valley, at Kasa Darbar or Dabar. CAS 50335, 5, 38.4���64.9 mm SL; Nepal: Chitwan Valley, Dudara River, tributary to Rapti River (from Churia Hills or Ranges). KU 28616, 40, 27.5���56.8 mm SL; Nepal: Sunsari, Bhantabari, Koshi River, seepage at Bhantabari, 26 �� 31 '30.0"N, 86 �� 58 ' 23.9 "E. KU 29155, 5, 27.8���32.1 mm SL; Nepal: Jhapa, Bhadrapur, Mechi River at Bhadrapur, 26 �� 32 ' 17.9 "N 88 �� 6 ' 6.1 "E. KU 28589, 12, 30.4���65.5 mm SL; Nepal: Sunsari, Koshi River, seepage at Koshi Tappu Wildlife Refuge, 26 �� 37 ' 23.9 "N 87 �� 1 ' 59.9 "E. KU 29380, 16 (3 c&s), 29.7���40.8 mm SL; Nepal: Udayapur, Phattepur, Trijuga River, downstream from irrigation dam at Phattepur, 26 �� 44 '24.0"N 86 �� 55 ' 54.1 "E. KU 29200, 14, 30.8���40.7 mm SL; Nepal: Morang, Belbari, Lohandra River at Belbari, 26 �� 39 '36.0"N 87 �� 24 ' 42.1 "E. KU 40642, 48, 42.0���56.0 mm SL; Nepal: Narayani, Chitwan, Budirapti Kohla at Bachauli- 3 Baghmara, 27 �� 35 ' 45.8 "N 84 �� 29 ' 10.6 "E. KU 40664, 34, 41.0��� 63.8 mm SL: Nepal: Narayani, Chitwan, tributary of the Rapti River, Chitwan National Park, 27 �� 34 ' 20.7 "N 84 �� 29 '47.0"E. OSUS 16679, 1, 39.5 mm SL; Nepal: Chitwan, Khoyeri Khola River, 10 km E of Narayangarh on Raj���Marg highway. OSUS 15957, 5, 45.1���54.5 mm SL; Nepal: Sunsari, Sapta Koshi River, fish market in Itahari. OSUS 16588, 1, 53.5 mm SL; Nepal: Nawalparasi, Narayani River, upstream from Tiger Tops Tented Camp. OSUS 15546, 1, 34.4 mm SL; Nepal: Chitwan, Buri Rapta Khola River at Saurcha. OSUS 16148, 1, 46.6 mm SL; Nepal: Nawalparasi, Marayoni River at Lainda Ghat. OSUS 15840, 2, 21.5, 27.0 mm SL; Nepal: Nawalparasi, Narayani River at Tribeni Ghat (above Tribeni Barrage). OSUS 15782, 2, 32.4, 36 mm SL; Nepal: Chitwan, Khageri Khola River, 12 km E of Narayangarh on Raj���Marg highway. UMMZ 205349, 42, 15.7���41.8 mm SL; Bangladesh: Dinajpur, Mahananda River at Tetulia, near location of Dak Bungalow, 26 �� 28 '60.0"N, 88 �� 19 '60.0"E. UMMZ 205352, 22, 11.1���50.7 mm SL: Bangladesh: Dinajpur, Keratoya River at Bhajanpur, just downstream from Indian border, 26 �� 28 '0.00"N 88 �� 28 '60.00"E. USNM 274804, 13, 28.4���48.7 mm SL; Nepal: Chitwan National Park, forest stream draining in to Rapti River. USNM 274788, 1, 53.9 mm SL; Nepal: Chitwan National Park, River running past Gaida Game Lodge, upstream of junction with Rapti River. Brahmaputra: AMNH 19648, 2 (1 c&s), 28.3, 34.3 mm SL; India: West Bengal, Tista River at Sevoke. BMNH 1932.9.19.1���3, 3, 64.7���66.7 mm SL; CAS-SU 41719, 1, 67.1 mm SL; CAS-SU 28700, 1, 64.7 mm SL; India: West Bengal, Siliguri. BMNH 2010.2.2.1���4, 4 (2 c&s; 1 SEM), 25.0-30.0 mm SL; India: West Bengal, Jalpaiguri District, Jorai River at Laskarpara, Barobisha town outskirts, 26 �� 28 ' 52.3 "N 89 �� 49 ' 29.9 E. NRM 52730, 2, 33.4��� 33.5 mm SL; India: Assam, Kaloni, Rani Garden (Ranigodam; ornamental fish farm and tea garden), 26 �� 3 '42.0"N 91 �� 37 '54.0"E. UMMZ 205346, 47, 19.2���55.5 mm SL; Bangladesh; Rangpur, Ghaghat River, 6 km E of Rangpur on Badarganj road, 25 �� 45 '0.0"N 89 �� 28 '60.0"E. UMMZ 244850, 1, 40 mm SL: India: West Bengal, Tista River at Tista Barrage, 26 �� 45 '10.0"N 88 �� 34 '11.0"E. UMMZ 244899, 4, 44.0���59.0 mm SL; India, West Bengal, Korola River in vicinity of Jalpaiguri, 26 �� 32 '42.0"N 88 �� 42 '32.0"E. UMMZ 244921, 3, 50.0���54.0 mm SL; India: West Bengal, Panga River at Krishibagan, 26 �� 28 '22.0"N, 88 �� 42 '8.0"E. ZMH 3212, 2, 56.7, 59.8 mm SL; India: Assam, Raimona. Meghna: FMNH 93596, 4, 43.5���63.8 mm SL; UMMZ 205339, 20, 46.3���73.3 mm SL; Bangladesh: Rangapani Khal, creek, 6 km NNW of Jaintapur on Sylhet���Shillong highway, 25 �� 10 '0.0"N 92 �� 5 '60.0"E. Sangu: UMMZ 205338, 5, 20.2���22.5 mm SL; Bangladesh: Chittagong, Chittagong Hill Tracts, Sangu River and small tributary creek ca. 2 km upstream from Bandarban, 22 �� 13 '0.0"N 92 �� 11 '60.0"E. Diagnosis. Psilorhynchus sucatio is distinguished from all other species of Psilorhynchus by the presence (vs. absence) of anteriorly directed radii over the anterior field of body scales, by its small pectoral fins (pectoral-fin length equal to pelvic-fin length vs. pectoral-fin length greater than pelvic-fin length), by having the rostral cap separate from the upper lip around the corner of the mouth (vs. rostral cap and upper lip continuous around corner of mouth), the posterior margin of the rostral cap triangular (vs. rounded), the shape of the second infraorbital (tube-like in lateral view, composed of sensory canal ossification only vs. plate like in lateral view), the shape of the basihyal (long, rod-like ossification vs. short spatula-like ossification), and by the absence (vs. presence) of a post-epiphyseal fontanelle. It is further distinguished from all species, except P. balitora, by having a complete covering of scales on its ventral surface between paired fins (vs. ventral surface between paired fins partially scaled, with a triangular to rectangular shaped scaleless patch along the ventral midline or with three to six pairs of flap-like structures supported by highly modified scales), and from all species except P. h o m a l o p t e r a by the absence (vs. presence) of the supraorbital bone. It is further distinguished from all members of the P. balitora and P. nudithoracicus species groups by its lower number of branched dorsal-fin rays (8 vs. 9���10), from all members of the P. nudithoracicus and P. homaloptera species groups by its lower number of principal caudal-fin rays (8���10 + 7��� 9, most commonly 9 + 9, vs. 9���10 + 8���9, most commonly 10 + 9) and from all members of the P. homaloptera group by its lower number of lateral line scales (33���36 vs. 39���48) and unbranched pectoral-fin rays (4���5 vs. 7���11). Description. General body shape as in Figures 3���7. Morphometric data are listed in Table 1 and select meristic characters in Tables 2 and 3. Body elongate, dorsal profile arched, rising moderately to dorsal-fin origin, sloping gently towards caudal peduncle. Body depth greatest at dorsal-fin origin, narrowest at base of caudal peduncle. Ventral profile straight from lower jaw to anal-fin origin, weakly concave from anal-fin origin to caudal-fin base Head and eye large, pupil ovoid, narrowest ventrally (Fig. 8). Mouth inferior, snout long, roughly half of head length, rounded anteriorly, its ventral surface bordered by a deep longitudinal groove on each side. Rostral cap and upper lip fused, separated by a shallow groove (Fig. 8���9); posterolateralmost part of rostral cap not continuous around corner of mouth, without contact to skin fold at posterolateral corner of mouth; posterior margin of rostral cap with obvious central indentation, giving anterior margin of upper lip a triangular appearance, with apex situated along ventral midline (Fig. 8, 9 A). Lower-jaw cushion, rounded anteriorly, with concave depression at center; superficial layer of lower-jaw cushion covered in globular papillae; globular papillae rimming posterior edge of lower lip larger than those situated more posteriorly. Upper lip covered with narrow, dagger-like unculi, ranging in height from ~ 10���20 ��m; lower jaw covered in low, cube-like unculi, ~ 5 ��m in height and width. Skin fold around posterolateral corner of mouth continuous anteriorly with posterolateralmost part of upper lip, not in contact with rostral cap; skin fold relatively smooth, non-papillated, without unculi or tubercles. Posterior edge of rostral cap, lower lip, skin fold, and globular papillae all densely covered with tastebuds (Fig. 9). Gill membranes joined to isthmus. Pre-epiphyseal fontanelle small, triangular. Post-epiphyseal fontanelle absent. Five infraorbital bones (IO 1-5). IO 1 platelike, largest of the series. IO 2���5 narrow tube-like bones, composed of sensory canal ossification only. Openings in preopercular portion of preopercular mandibular canal 5. Openings in nasal portion of supraorbital canal 3. Openings in parietal portion of temporal canal 2. Anguloarticular portion of preopercular mandibular canal, parietal portion of supraorbital canal and supraoccipital portion of temporal canal absent. Fifth ceratobranchial with a single row of four needle-like teeth. Hyoid bar with three branchiostegal rays; anteriormost greatly reduced in size. Basihyal a long, slender rod-shaped bone, extending far anterior of hyoid bar commissure along ventral midline. Anterior swimbladder chamber surrounded by a thick peritoneal tunic, partially enclosed in a bony capsule formed anteriorly by lateral process of 2 nd vertebral centrum and laterally by outer arm of os suspensorium. Posterior swimbladder chamber greatly reduced in size. Dorsal-fin rays ii. 8 (48). Anal-fin rays iii. 5 (3) or ii. 6 (42). Principal caudal-fin rays 8 + 8 (1), 9 + 8 (12), 9 + 9 (29), 10 + 8 (1) or 10 + 9 (1), dorsal procurrent rays 3 (4), 4 (8) or 5 (2), ventral procurrent rays 3 (8), 4 (4) or 5 (1). Pectoral fin rays iv. 7 (5), iv. 8 (21), iv. 9 (20) or v. 8 (2), pelvic-fin rays ii. 6 (1) or ii. 7 (47). Paired fins horizontally oriented, roughly equal in size. Pectoral fin not reaching vertical through dorsal-fin origin, reaching three to five scale rows anterior to pelvic-fin origin when adpressed. Pelvic-fin origin posterior to dorsal-fin origin, insertion of anteriormost point opposite second branched dorsal-fin ray. Well-developed unculiferous paired-fin pads present along ventral surface of four anteriormost pectoral-fin rays and two anteriormost pelvic-fin rays. Dorsal fin high, triangular in shape with weakly pointed tip; posterior margin weakly concave. Anal fin relatively large, triangular in shape with weakly pointed tip; posterior margin weakly concave; not reaching caudal-fin base when adpressed. Caudal fin moderately forked, tips of upper and lower lobes weakly rounded. Scales cycloid, large, with three or four well-developed radii over anterior and posterior fields of scale body. 33 (3), 34 (15), 35 (22) or 36 (3) scales along lateral line, plus 1 (11), 2 (28) or 3 (5) on base of caudal fin. 3.5 / 1 / 2 transverse scale rows from dorsal-fin origin to pelvic-fin origin, 10 scale rows around caudal peduncle, 9 (2), 10 (9), 11 (31) or 12 (3) predorsal scales, 9 (5), 10 (28), 11 (14) or 12 (1) scales between anus and anal-fin origin. Ventral surface between paired fins scaled. Total number of vertebrae 34 (2), 35 (3), 36 (8), or 37 (2), consisting of 17 + 17 (1), 17 + 19 (1), 18 + 16 (1), 18 + 17 (3), 18 + 18 (7) or 18 + 19 (2) abdominal and caudal vertebrae. Small conical tubercles with hard keratinized tip distributed over lateral and ventral surfaces of head, including snout and rostral cap, and along dorsal margin of orbit (Fig. 8). Tubercles present along posteroventral margin of rostral cap larger than those positioned more anteriorly on rostral cap and other surfaces of head. Head tuberculation more strongly developed in males. Scales situated posterior to occiput along dorsal midline and dorsolateral body surface edged with three or four small conical tubercles in males. Strip of minute conical tubercles present along dorsal surface of unbranched pectoral-fin rays in males. Single row of minute conical tubercles present along dorsal surface of unbranched and anteriormost branched pectoral-fin rays in females and anteriormost branched pectoral-fin ray in males. Anteriormost branched pectoral-fin ray also with single row of minute conical tubercles along ventral surface in both sexes. Dorsal surface of anteriormost pelvic-fin ray and lateral surface of last unbranched dorsal-fin ray with single row of minute conical tubercles in males only. Irregularly placed minute conical tubercles also present throughout paired-fin pad along ventral surface of anteriomost pelvic-fin ray of males. Coloration. In alcohol body background color light cream (Fig. 3���7). Occiput uniformly brown. Pigmentation features along dorsal surface posterior to occiput variable. Anterior to dorsal fin, majority of specimens with a faint brown blotch along dorsal midline, situated two to three scales posterior to occiput, and a small but prominent dark brown spot situated at anteriormost point of dorsal fin. Several specimens exhibit irregularly shaped brown markings (blotches or short streaks) between these two latter features, which may also be situated along the dorsal midline or situated slightly lateral to the midline. Below dorsal fin, majority of specimens exhibit a large brown saddle, extending along dorsal midline between last unbranched and 6 th branched dorsal-fin rays. Posterior to dorsal fin, majority of specimens exhibit a single brown saddle (smaller in size than saddle situated below dorsal fin), situated along dorsal-midline just anterior to midway point between dorsal fin and caudal-fin base. Several specimens exhibit irregularly shaped brown markings anterior and posterior to post-dorsal saddle. Saddle situated below dorsal fin extending ventrad 1���2 scale rows on body side, separate from round to squarish brown blotches arranged in a longitudinal row on flank. Dorsal saddle situated between dorsal fin and caudal-fin base not extending on to lateral surface of body. Flank with 6���8 (most commonly 7) round to squarish dark brown lateral blotches arranged in a longitudinal row. In specimens with 7, first situated posterodorsal to opercular opening, extending beneath lateral-line scales 2 / 3���6 / 7, second extending beneath lateral-line scales 9 / 10���12 / 13, third extending beneath lateral-line scales 17 / 18��� 19 / 20, fourth extending beneath lateral-line scales 21 / 22���23 / 24, fifth extending beneath lateral line scales 25 / 26��� 27 / 28, sixth extending beneath lateral line scales 29 / 30���32 / 33, seventh situated at base of caudal fin, extending beneath lateral-line scales 34 / 35 ��� 35 / 36. Scales in lateral line scale row and scale row directly below lateral line scale row with large chocolate brown melanophores concentrated at scale center, giving appearance of a horizontal stripe along lower half of flank. Stripe most prominent in juvenile specimens, occluding lower portion of round to squarish dark brown blotches arranged in a longitudinal row along flank. In larger specimens (over 30 mm SL) stripe is less prominent. Scales in rows dorsal to lateral line scale row with fine dusting of light brown melanophores at center. Scales in lowermost scale row on body (excluding scale situated at pelvic-fin origin) without pigmentation, providing a striking contrast to ventral edge of horizontal stripe along lower portion of flank. Unscaled base of pectoral fin and scale in lowermost body scale row situated at pelvic-fin origin peppered with small dark brown melanophores, forming indistinct pectoral-base and pre-pelvic spots, respectively. Small dark brown melanophores forming indistinct strip between tip of snout and anterior margin of orbit. Skin over opercle densely scattered with dark brown melanophores. Table 3. Summary of pores in the cephalic sensory in select members of Psilorhynchus. See text for explanation of numbers. Absence of a particular canal is denoted by a ���-���. Otic Preopercular mandibular Infraorbital canal Supraorbital canal Canal Temporal Canal Anguloarticular Preopercle IO 1 IO 2 IO 3 IO 4 IO 5 Nasal Frontal parietal Parietal supraoccipital Ventral surface largely devoid of pigment except for brown melanophores along anterior edge of rostral cap, ventrolateral border of snout, and ventral margin of infraorbital series. Paired fins marked proximally with a small brown blotch, formed by melanophores located along interradial membranes between bases of anteriormost rays. Dorsal surface of anteriormost rays of pectoral and pelvic fins marked with 1���4 small brown blotches, giving paired fins a mottled appearance anteriorly. Anterior edge of dorsal fin with three dark brown markings; one positioned at base of anteriormost rays, formed by brown melanophores located along interradial membranes between fin-ray bases; second located midway along length of last unbranched ray and first branched ray, formed by melanophores positioned along lateral edge of rays; third located distally, close to tip of last unbranched ray and first branched ray, formed by melanophores positioned along lateral edge of rays. Anal fin hyaline or with one or two small brown blotches formed by melanophores positioned along lateral surface of anteriormost rays. Caudal fin pigmentation highly variable. Majority of specimens with dark brown blotch over base of central caudal-fin rays and irregular shaped dark brown marking on upper and lower lobes. In several specimens markings along lower lobe and blotch at base of caudal fin are confluent. Distribution and habitat. Psilorhynchus sucatio is known with certainty from the Ganges River drainage in Bangladesh, India (West Bengal) and Nepal, the Brahmaputra River drainage in Bangladesh and India (Assam and West Bengal), and the Meghna and Sungu River drainages in Bangladesh (Fig. 10). David (1953) reported P. sucatio from the Damodar River drainage in India (southwestern West Bengal) and Arunachalam & Muralidharan (2008: 412) also report the presence of P. sucatio in the Indian states of Meghalaya and Tripura, without further comment. Rainboth (1983) reports that P. s u c a t i o is most commonly collected close to emergent or overhanging vegetation along the edge of sandy streams (based on collections made in Bangladesh). Remarks. Psilorhynchus sucatio, as understood herein, is a widespread species, occurring throughout much of the Ganges and Brahmaputra drainages in northeastern India and northwestern Bangladesh, the Ganges drainage throughout southern Nepal (Shrestha, 1980; Shrestha, 2008), and the Meghna and Sangu drainages in eastern Bangladesh (Rainboth, 1983). Within India, Menon (1999) reports P. sucatio from the states of Assam, Meghalaya, Uttar Pradesh (possibly in reference to P, Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on pages 205-222, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175, {"references":["Hamilton, F. (1822) An Account of the Fishes Found in the River Ganges and its Branches. Archibald Constatable and Co., Edinburgh, Scotland, 405 pp.","David, A. (1953) On some new records of fish from Damodar and Mahanadi River systems. Journal of the Zoological Society of India, 5, 243 - 254.","Arunachalam, M. & Muralidharan, M. (2008) Description of a new species of the genus Psilorhynchus (Teleostei: Psilorhynchidae) from a western Ghat stream in southern India. The Raffles Bulletin of Zoology, 56, 405 - 414.","Rainboth, W. J. (1983) Psilorhynchus gracilis, a new cyprinoid fish from the Gangetic lowlands. Proceedings of the California Academy of Sciences, 43, 67 - 76.","Shrestha, J. (1980) Fishes of Nepal. Curriculum Development Centre, Tribhuvan University, Kathmandu, xviii + 318 pp.","Shrestha, T. K. (2008) Ichthyology of Nepal: A Study of Fishes of the Himalayan Waters. Himalayan Ecosphere, Kathmandu, 388 pp.","Conway, K. W., Mayden, R. L., Shrestha, J. & Edds, D. (2012) Redescription of the Nepalese endemic torrent minnow Psilorhynchus pseudecheneis Menon & Datta (Teleostei: Psilorhynchidae) with comments on P. homaloptera Hora & Mukerji. Ichthyological Exploration of Freshwaters, 23, 193 - 210.","Ramaswami, L. S. (1952) Skeleton of cyprinoid fishes in relation to phylogenetic studies. II. The systematic position of Psilorhynchus M'Clelland. Proceedings of the National Institute of Science, India, 18, 141 - 150.","Conway, K. W. & Kottelat, M. (2007) A new species of Psilorhynchus (Teleostei: Psilorhynchidae) from the Ataran River drainage, Myanmar, with comments on the generic name Psilorhynchoides. Zootaxa, 1663, 47 - 57.","Tilak, R. & Husain, A. (1980) Description of a new psilorhynchid, Psilorhynchus sucatio nudithoracicus (Psilorhynchidae: Cypriniformes) from Uttar Pradesh with notes on zoogeography. Mitteilungen aus dem Zoologischen Museum in Berlin, 56, 35 - 40.","Talwar, P. K. & Jhingran, A. G. (1991) Inland Fishes of India and Adjacent Countries. Oxford and IBH Publishing Company, New Delhi, 2 vols., xvii + 1158 pp.","Conway, K. W. & Mayden, R. L. (2008 a) Psilorhynchus breviminor, a new species of psilorhynchid from Myanmar (Ostariophysi: Psilorhynchidae). Ichthyological Exploration of Freshwaters, 19, 111 - 120.","Conway, K. W. & Mayden, R. L. (2008 b) Two new species of Psilorhynchus (Ostariophysi: Psilorhynchidae) with the redescription of P. balitora. Ichthyological Exploration of Freshwaters, 19, 215 - 232.","Conway, K. W. & Kottelat, M. (2010) Two new species of torrent minnow (Ostariophysi: Psilorhynchidae: Psilorhynchus) from Western Myanmar. The Raffles Bulletin of Zoology, 58, 259 - 267.","Conway, K. W. & Britz, R. (2010) Three new species of Psilorhynchus from Myanmar (Ostariophysi: Psilorhynchidae). Zootaxa, 2616, 1 - 16."]} more...

Psilorhynchus hamiltoni, new species Figs. 23, 24 Holotype. UMMZ 249903, 30.6 mm SL; India: West Bengal, Tista River at Tista Barrage, 105 m asl, 26 �� 45 '1.0"N 88 �� 35 '11.0"E, H. H. Ng et al., 15 April 2004. Paratypes. UMMZ 249904, 5 (1 c&s; 1 SEM stub), 25.8���26.3 mm SL: same data as holotype. Diagnosis. A member of the P. balitora species group, distinguished from all other members by the following combination of characters: lateral stripe well-developed; 7���11 round to squarish lateral blotches; 6���7 dorsal saddles; dorsal saddles without contact to lateral blotches; lateral line scales 34���35; principal caudal-fin rays 9 + 8��� 9; pectoral-fin rays v���vi. 9���11; total vertebrae 36 (18 + 18); two branchiostegal rays; parietal portion of temporal sensory canal with 2 openings; ventral surface between paired fins with a broad rectangular scaleless patch. Description. General body shape as in Figure 23. Morphometric data are listed in Table 1 and select meristic characters in Tables 2 and 3. Body elongate, dorsal profile weakly arched. Body depth greatest at point slightly anterior to dorsal-fin origin, narrowest at base of caudal peduncle. Ventral profile straight from lower jaw to analfin origin, weakly concave from anal-fin origin to caudal-fin base. Head and eye large, pupil elliptical, with longest axis of ellipse orientated along dorsal-ventral body axis. Mouth inferior, relatively wide (Fig. 24). Snout short, rounded anteriorly, its ventral surface bordered by a deep longitudinal groove on each side. Rostral cap and upper lip fused, separated by a shallow groove; posterolateralmost part of rostral cap continuous around corner of mouth, contacting skin fold at posterolateral corner of mouth; posterior margin of rostral cap smooth. Lower lip portion of lower-jaw cushion broadly rectangular, anterior edge straight; superficial layer of lower-jaw cushion covered in low, rounded globular papillae, separated by deep grooves; majority of globular papillae concentrated directly posterior to middle of lower lip portion of lower-jaw cushion, becoming scarcer laterally. Upper lip covered with narrow, dagger-like unculi, ranging in height from ~ 10���20 ��m, becoming increasingly longer towards mouth opening; lower jaw unculi not examined. Skin fold around posterolateral corner of mouth large and flap-like, continuous anteriorly with posterolateralmost part of upper lip and rostral cap; outer edge of skin fold smooth, globular papillae absent; tubercles present around outer edge of skin fold. Posterior edge of rostral cap, lower lip, skin fold, and globular papillae all densely covered with tastebuds. Gill membranes joined to isthmus. Following osteological features based on a single c&s specimen. Pre-epiphyseal fontanelle small, triangular. Post-epiphyseal fontanelle present, long, irregularly shaped (pinched along its center; Fig. 13 L), separated from pre-epiphyseal fontanelle by wide expanse of frontal. Five infraorbitals (IO 1���5). IO 1���3 platelike, IO 1 largest of the series, IO 4���5 narrow tube-like bones, composed of sensory canal ossification only. Anguloarticular portion of preopercular mandibular canal and parietal portion of supraorbital canal absent. Openings in preopercular portion of preopercular mandibular canal 4. Openings in nasal portion of supraorbital canal 3. Openings in parietal portion of temporal canal 2. Supraoccipital portion of temporal canal open. Fifth ceratobranchial with a single row of four needle-like teeth. Branchiostegal rays 2; anteriormost branchiostegal ray articulating with medial face of anterior ceratohyal absent. Anterior swimbladder chamber surrounded by a thick peritoneal tunic, partially enclosed in a bony capsule formed anteriorly by lateral process of 2 nd vertebral centrum and laterally by outer arm of os suspensorium. Posterior swimbladder chamber greatly reduced in size. Dorsal-fin rays iii. 9 (5, including holotype [*]) or iii. 8 (1). Anal-fin rays ii. 6 (6). Principal caudal-fin rays 9 + 9 (2 *) or 9 + 8 (4), dorsal procurrent rays 9, ventral procurrent rays 6. Pectoral fin rays vi. 9 (1), vi. 10 (4 *) or vi. 11 (1), pelvic fin rays ii. 7 (6). Paired fins horizontally placed, pectoral fins larger than pelvic fins. Pectoral fin reaching vertical through dorsal-fin origin when adpressed. Pelvic-fin origin posterior to dorsal-fin origin, insertion opposite second or third branched dorsal-fin ray. Well-developed unculiferous paired-fin pads present along ventral surface of four-five anteriormost pectoral fin rays and two anteriormost pelvic-fin rays. Dorsal fin moderately high, triangular in shape with weakly pointed tip; posterior margin weakly concave. Anal fin small, triangular in shape with weakly pointed tip; posterior margin weakly concave; not reaching caudal-fin base when adpressed. Caudal fin weakly forked, tips of both lobes rounded. Scales cycloid, large, with several well-developed radii over posterior field of scale body. 34 (1) or 35 (2 *) scales along lateral line, plus 2 (3) pored scales on base of caudal fin. Number of transverse scale rows from dorsalfin origin to pelvic-fin origin not obtainable (scales between dorsal fin and lateral line missing in all type material). 10 scale rows around caudal peduncle, 10 (1) or 11 (2 *) predorsal scales, 10 (3) or 11 (1 *) scales between anus and anal-fin origin. Ventral surface between paired fins without scales. Total number of vertebrae 36, consisting of 18 + 18 (1) abdominal and caudal vertebrae. Small conical tubercles with poorly keratinized tip distributed over lateral and dorsal surfaces of head, including snout and anteroventral region of rostral cap. Posteroventral margin of rostral cap with small dagger-like tubercles. Body and fin tuberculation not developed in available material. Coloration. In alcohol body background color light cream (Fig. 23). Occiput dark brown. Dorsal surface between occiput and dorsal fin with two dark brown saddles, first situated at midpoint between occiput and dorsalfin origin, second situated at dorsal-fin origin. Number of dorsal saddles posterior to dorsal-fin origin variable, with six present in holotype and four present in paratypes. In paratypes, first post-dorsal-fin origin saddle situated below middle of dorsal fin, between insertions of branched dorsal-fin rays 4���6, second situated directly between dorsalfin and anal-fin origin, third situated directly above middle of anal fin, fourth situated at base of caudal fin. In holotype, post-dorsal-fin origin saddles narrower than those of paratypes. First situated at same position as in paratypes, second situated closer to insertion of last dorsal-fin ray than point opposite anal-fin origin, third situated slightly anterior to point opposite anal-fin origin, fourth situated directly above middle of anal fin, fifth situated at center of caudal peduncle, sixth situated at base of caudal fin. Saddle situated at dorsal-fin origin largest of series. Dorsal saddles extending ventrally 1���2 scale rows on body side, without contact with lateral blotches or lateral stripe. Flank with 7 (2), 8 (2), 9 (1) or 11 (1 *) small round to squarish dark brown blotches arranged in a longitudinal row. Size and position of lateral blotches along flank highly variable, excluding first, situated posterodorsal to opercular opening, and last, situated at caudal-fin base. Lateral stripe dark brown, well developed. Scales situated over anterodorsal surface of body, anterior to dorsal fin, with scattering of light brown melanophores along posterior edge, forming weak reticulate pattern. Scales in L+ 1 row dorsal to lateral line scales 10���25 with small light brown spot at center. Scales in L- 1 row ventral to lateral line scales 6���11 with small dark brown spot at center. Unscaled base of pectoral fin and scales adjacent to pelvic-fin origin peppered with small dark brown melanophores, forming indistinct pectoral-base and pre-pelvic spots, respectively. Lateral surface of snout and skin over opercle densely scattered with dark brown melanophores. Ventral surface largely devoid of pigment except for a small patch of brown melanophores situated beneath scales at anal-fin origin and a short line of melanophores posterior to anus, running along ventral midline from 2 nd to 5 th scale in scale row running between anus and anal-fin origin. Dorsal surface of pectoral- and pelvic-fin rays marked with small melanophores. Dorsal fin with weak stripe across center, formed by aggregations of small dark brown melanophores at fork of branched rays. Anal fin hyaline. Caudal fin with dark brown triangular blotch at base, orientated with posteriormost tip of triangle extending into base of lower lobe. Additional small dark brown markings variably present throughout upper and lower lobes. Distribution. Psilorhynchus hamiltoni is known currently only from the type locality on the Tista River at the Tista Barrage (Fig. 21). This locality has been described previously by Ng (2005) and Conway & Mayden (2008 b). Etymology. Named in honor of the exceptional Scottish naturalist Francis Hamilton (1762���1829), a pioneer of Indian ichthyology, who spent more than 17 years surveying the freshwater fish fauna of large areas of the Indian subcontinent. Remarks. The six specimens on which the above description is based were collected together with specimens of P. balitora, and all were subsequently catalogued together (as P. balitora) in UMMZ 244849. During their redescription of P. balitora, Conway & Mayden (2008 b) examined only the five largest specimens from UMMZ 244849 (all P. balitora), overlooking the fact that this lot contained individuals belonging to two separate species (Conway, pers. obs.). The mixed nature of this lot did not became apparent until later (in 2010), when one of us (KWC) reinvestigated its contents and noticed that the six smallest specimens do not possess scales along the ventral surface of the body between the paired fins (an area that is invariably scaled in P. balitora; Conway & Mayden, 2008 b), which prompted further investigation and ultimately led to the conclusion that they belonged to an undescribed species. In addition to the absence of scales along the ventral surface between the paired fins, P. hamiltoni can be further distinguished from P. balitora by its higher number of lateral line scales (34���35 vs. 30���32), caudal vertebrae (18 vs. 15���16), and total vertebrae (36 vs. 31���33), a lower number of branchiostegal rays (two vs. three) and openings in the parietal portion of the temporal canal (two vs. three), and by having a large post-epiphyseal fontanelle that is bordered anteriorly by the frontals (vs. post-epiphyseal fontanelle small, restricted to posterodorsalmost portion of neurocranium, bordered anteriorly by the parietals). Features of the color pattern also serve to distinguish P. hamiltoni from P. balitora. In P. hamiltoni the lateral stripe is well developed, whereas in P. balitora (and all other members of the P. balitora species group) the lateral stripe is poorly developed. In P. hamiltoni the saddles along the dorsal surface of the body do not make contact with the lateral blotches along the body side, whereas in P. balitora (and all other members of the P. balitora species group, excluding P. rahmani), the saddles extend far enough ventrally (over the side of the body) to make contact with the lateral blotches. All available specimens of P. hamiltoni are presumably juveniles or small adults, ranging in size from 25.7��� 30.6 mm SL. Despite their small size, these specimens exhibit small round tubercles over the dorsal and lateral surfaces of the head and snout. Tubercles are, however, absent from the body and fins. SEM investigation of the mouthparts of a single paratype (26.3 mm SL) revealed the presence of small (but nevertheless well developed) conical tubercles on the surface of the skin-flap at either corner of the mouth and small dagger-shaped tubercles along the posteroventral edge of the rostral cap (Fig. 24) that could not be observed in the holotype or other paratypes using light microscopy. Dagger-shaped tubercles (with tips oriented caudally) are common along the posteroventral margin of the rostral cap in other species of Psilorhynchus (for example see Fig. 4 in Conway et al., 2012; Fig. 25 herein) and are easily observed with light microscopy in well-preserved specimens. The presence of tubercles over the surface of the skin-flap positioned at the corner of the mouth appears to be less common, as evidenced by their absence in P. s u c a t i o (Fig. 9) and P. nudithoracicus (Fig. 19). In addition to the paratype of P. hamiltoni, we have observed these structures only in the single individual of P. balitora examined using SEM (Fig. 25). Though once considered to be a relatively minor component of the South Asian ichthyofauna (Hora, 1920), recent investigations have revealed the Psilorhynchidae to be surprisingly diverse, with twelve new species described since 2007 (Conway & Kottelat, 2007, 2010; Arunachalam et al. 2007; Nebeshwar et al. 2007; Arunachalam & Muralidharan 2008; Conway & Mayden 2008 a, b; Conway & Britz, 2010). Given the pace at which new species of Psilorhynchus continue to be described, the discovery of an additional species in the Brahmaputra drainage of northeastern India is not surprising and further highlights our incomplete knowledge of the Indian freshwater ichthyofauna. The discovery of P. hamiltoni in a ���well-examined��� lot of Psilorhynchus was, however, completely unexpected, and its description should serve as a cautionary tale for those that may be tempted to ignore those smaller, harder to reach specimens, at the bottom of the jar., Published as part of Conway, Kevin W., Dittmer, Drew E., Jezisek, Laci E. & Ng, Heok Hee, 2013, On Psilorhynchus sucatio and P. nudithoracicus, with the description of a new species of Psilorhynchus from northeastern India (Ostariophysi: Psilorhynchidae), pp. 201-243 in Zootaxa 3686 (2) on pages 232-236, DOI: 10.11646/zootaxa.3686.2.5, http://zenodo.org/record/284175, {"references":["Ng, H. H. (2005) Pseudolaguvia foveolata, a new catfish (Teleostei: Erethistidae) from northeastern India. Ichthyological Exploration of Freshwaters, 16, 173 - 178.","Conway, K. W. & Mayden, R. L. (2008 b) Two new species of Psilorhynchus (Ostariophysi: Psilorhynchidae) with the redescription of P. balitora. Ichthyological Exploration of Freshwaters, 19, 215 - 232.","Conway, K. W., Mayden, R. L., Shrestha, J. & Edds, D. (2012) Redescription of the Nepalese endemic torrent minnow Psilorhynchus pseudecheneis Menon & Datta (Teleostei: Psilorhynchidae) with comments on P. homaloptera Hora & Mukerji. Ichthyological Exploration of Freshwaters, 23, 193 - 210.","Hora, S. L. (1920) Revision of the Indian Homalopteridae and of the genus Psilorhynchus (Cyprinidae). Records of the Indian Museum, 19, 195 - 215.","Conway, K. W. & Kottelat, M. (2007) A new species of Psilorhynchus (Teleostei: Psilorhynchidae) from the Ataran River drainage, Myanmar, with comments on the generic name Psilorhynchoides. Zootaxa, 1663, 47 - 57.","Conway, K. W. & Kottelat, M. (2010) Two new species of torrent minnow (Ostariophysi: Psilorhynchidae: Psilorhynchus) from Western Myanmar. The Raffles Bulletin of Zoology, 58, 259 - 267.","Arunachalam, M., Muralidharan, M. & Sivakumar, P. (2007) Psilorhynchus amplicephalus, a new species from Balishwar river of Assam, India. Current Science, 92, 1352 - 1354.","Nebeshwar, K., Bagra, K. & Das, D. N. (2007) A new species of the cyprinoid genus Psilorhynchoides Yazdani et al. (Cypriniformes: Psilorhynchidae) from Arunachal Pradish, India. Zoos' Print Journal, 22, 2632 - 2636.","Arunachalam, M. & Muralidharan, M. (2008) Description of a new species of the genus Psilorhynchus (Teleostei: Psilorhynchidae) from a western Ghat stream in southern India. The Raffles Bulletin of Zoology, 56, 405 - 414.","Conway, K. W. & Mayden, R. L. (2008 a) Psilorhynchus breviminor, a new species of psilorhynchid from Myanmar (Ostariophysi: Psilorhynchidae). Ichthyological Exploration of Freshwaters, 19, 111 - 120.","Conway, K. W. & Britz, R. (2010) Three new species of Psilorhynchus from Myanmar (Ostariophysi: Psilorhynchidae). Zootaxa, 2616, 1 - 16."]} more...