Clupisoma prateri Hora, 1937

Ferraris, Carl J. & Jr, 2004, A new species of the Asian schilbid catfish genus Clupisoma from Myanmar, with a redescription of Clupisoma prateri Hora (Osteichthyes: Siluriformes: Schilbidae), Zootaxa 437, pp. 1-10 : 6-9

Clupisoma prateri Hora, 1937 ( Fig. 2 )

Clupisoma prateri Hora, 1937: 671 , figs. 2b, 3b, 6 (type locality: Burma). Holotype: ASB Dup Cat. no. 219 [housed at ZSI]).

Material examined. All specimens from Myanmar: AMNH 7808 (1, 161 mm SL), Monywa; BMNH 1889.2.1.2411–2 (2, 132–133 mm SL), Moulmein; BMNH 1889.2.1.2462 (1, 110 mm SL), Irrawaddy; BMNH 1891.11.30.184 (1, 116 mm SL), Sittang River; CAS 88898 (2, 123–124 mm SL), USNM 372157 (1, 188 mm SL), Yangon market; CAS 88908 (1, 122 mm SL), Nyaung­U market; CAS 94939 (1, 146 mm SL), Mandalay market; NRM 31186 (2, 178–180 mm SL), Shweli River; NRM 31187 (9, 92– 187 mm SL), Moulmein; NRM 31190 (5, 70–91 mm SL), Rangoon; NRM 31189 (1, 123 mm SL), Kyondo; USNM 372495 (2, 178–184 mm SL), Thanlyin market.

Diagnosis. A species of Clupisoma in which the pectoral spine extends at least to the base of the pelvic fin, the abdomen is markedly keeled from the level of the pectoral­fin origin to the anus, pectoral fin with 12 or 13 segmented rays, anal fin with 37 to 41 branched rays, and first gill arch with at least 20 rakers. The body is silvery, except for a dorsal greenish band that extends only slightly ventral of the middorsal line of the body.

Description. (based primarily on NRM 31187) Body elongate, compressed; depth at dorsal origin nearly 5 in SL and approximately equal to HL; dorsal profile of body slightly convex, nearly horizontal posterior of dorsal fin, straight between dorsal­fin origin and snout; abdomen sharply keeled from level of pectoral­fin origin to vent; vent located just anterior to anal­fin origin. Lateral line complete, straight, with short branches extending obliquely above and, mostly, below for entire length. Vertebral column with 48 to 50 vertebrae and 13 or 14 ribs.

Head nearly 5 in SL; compressed posteriorly, nearly as high as wide at middle of eye; opercular opening broad, extending from level of lateral line to anterior of isthmus, opercular membranes not connected to isthmus; posterolateral margin of operculum with posteriorly directed, fleshy lobe; tip of lobe rounded.

Snout acutely rounded in lateral view, in dorsal view, snout margin trilobed, lobes not well defined; anterior naris located on anterior margin of snout; naris round and directed anteriorly, narial opening surrounded by reflexed skin; posterior naris an elongated slit, located slightly posterodorsal and medial to anterior naris, naris nearly transversely oriented, but medial end somewhat posterior of anterior end; anterior narial margin with convex flap of skin that often covers narial opening; nares large, width of posterior naris greater than that of internarial distance.

Eye ventrolaterally placed, but also visible from dorsal view; eye positioned somewhat below middle of head, middle of pupil ventral to level of anterior naris; eye covered laterally with adipose tissue, with ovoid, vertically elongated opening.

Mouth subterminal, upper jaw overhangs lower jaw; mouth opening small, completely anterior to anterior orbital margin; premaxillary tooth plate arched, teeth slender and conical, in two or three irregular rows medially, as many as five rows laterally; upper jaw teeth exposed when mouth is closed. Tooth plate on lower jaw crescentic, teeth slender, conical and somewhat larger than premaxillary teeth, in several rows near symphysis, reduced to one row laterally. Palatal tooth patch elongate, ovoid, not reaching to midline; teeth conical, smaller than those of premaxilla. Teeth in five or six irregular rows. Accessory tooth patches absent from upper jaw and palate.

Gill rakers: 20 to 25 on lateral face of first arch (5 to 8 on dorsal limb and 15 to 18 on lower limb).

Barbel in four pairs, all barbels rest in shallow groove in skin, at least basally. Nasal barbel small, thread­like; extending from lateral margin of posterior naris to level of pupil. Maxillary barbel extends from posterior of anterior naris to tip of adpressed pelvic fin; mental barbels in two pairs, barbel bases originate in transverse row at level of posterior naris; inner mental barbel extends to level of pectoral spine origin, outer mental barbels slightly shorter.

Dorsal fin located in anterior one­third of SL, fin base short, about equal to snout length and about 1/2 of length of dorsal spine; fin much smaller than pectoral fin; dorsal fin with spinelet, slender spine and seven branched rays; spine with fine roughened ridge anteriorly, and with fine retrorse serrations on distal half of posterior margin; fin margin regressive, nearly straight; length of last ray less than one­half that of first. Dorsal fin rays: II,7. Adipose fin tiny, located above posterior quarter of anal­fin base; absent is some specimens.

Caudal fin deeply forked, lobes pointed and symmetrical; outer principal rays somewhat less than 3 times length of middle rays. Principal caudal fin rays: i,7,8,i.

Anal­fin origin located just anterior to level of middle of SL; anal­fin base long, about 3 times in SL. Fin margin slightly concave anteriorly, nearly straight posteriorly; posterior rays shortest. Last ray without membranous connection to caudal peduncle. Anal­fin rays: iv–v, 37–41.

Pelvic fin moderate in size, its length about equal to length of dorsal­fin spine; fin origin about one dorsal­fin base length posterior to posterior insertion of dorsal fin; adpressed fin just shy of anal­fin origin. Pelvic­fin rays: i, 5.

Pectoral fin large, triangular, first branched ray longest. Pectoral­fin spine long, stout, adpressed fin extends to past level of dorsal fin base, and past pelvic­fin origin; spine with fine roughened ridge anteriorly, and with fine retrorse serrations on distal half of posterior margin. Pectoral­fin rays: I, 12–13.

Coloration. Body greenish above, silvery below. Anteriorly, green extends to lateral line, for most of body greenish area limited to dorsum. Head dark dorsal to level of orbit, silvery laterally and ventrally; snout margin pale. Ventral surface of head and abdomen pale. Dorsal fin pale dusky anteriorly, posterior rays pale. Adipose fin pale. Caudal fin mostly pale, fin margin with broad dusky band. Anal and pelvic fins pale. Pectoral fin dusky on basal part of anterior rays, posterior rays and fin margin pale. Maxillary barbel dusky basally, other barbels pale.

Distribution. Found widely distributed in the lower and middle reaches of the Irrawaddy River, the lower reaches of the Salween River, and the Bago and Sittang rivers of Myanmar.

Remarks. Hora (1937: 672–673) distinguished Clupisoma prateri from Clupisoma garua on the basis of seven characters: “nasal barbels extend considerably beyond the front margin of the eye; maxillary barbel extend to about the middle of pelvics and sometimes to the commencement of the anal fin; mandibular barbels extend to the hind border of operculum; pectorals extend beyond pelvic­fin origin; anal with about 40 to 44 rays; whole of dorsal fin considerably in advance of pelvics; and abdominal edge keeled throughout in front of vent.” Although Hora stated that the specimens he examined were not in good condition, the characters he observed fit well with those found in the specimens examined here from the lower Irrawaddy basin and nearby rivers. Therefore, even in the absence of a direct examination of the holotype, there is no doubt that the lower Irrawaddy specimens are Clupisoma prateri .

Characters that separate this species from Clupisoma roosae , the only other species in Myanmar, are summarized in Table 1 as well as the Remarks section of that species. Clupisoma prateri is distinguished from all other congeners by the extent of the midventral abdominal keel, which extends from just posterior of the isthmus to the vent.

In the original description of Clupisoma prateri the holotype is listed with two different catalog numbers. In the caption for figure 6 and in the table on page 673, the number is listed as "Dup. Cat. No. 219," but in the text on page 673 it is listed as Duplicate Catalogue No. 213. Menon and Yazdani (1968) cite the catalog number as ASB Dup. Cat. No. 219 [housed at ZSI], which they presumably verified against the specimen and is, therefore, used herein.

Comparative material examined.

Clupisoma garua: All specimens from India: BMNH 1889.2.1.2443–2447 (8, 73–145 mm SL), Calcutta; BMNH 1858.8.15.127 (1, 128 mm SL), Ganges; SU 34839 (11, 109–167 mm SL), Hugli River, Calcutta; SU 14579 (1, 179 mm SL) Megna River, Bengal; NRM 40588 (2, 232–248 mm SL), Dibrugarh Market; NRM 40599 (1, 106 mm SL), Dibrugarh Market.

Clupisoma sinensis : CAS 93282 (1, 166 mm SL), Laos, Nam Theun; CAS 68201 (2, 164–174 mm SL), Thailand, Mukdahan Market.

Figures

FIGURE 2. Clupisoma prateri Hora, 1937, CAS 88908 (122 mm SL).