Clupisoma roosae, Carl J. Ferraris, Jr., 2004

Carl J. Ferraris, 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 : 2-6

Clupisoma roosae n. sp.

(Fig. 1)

Holotype. NRM 40030 (160 mm SL) Myanmar, Kachin State, Myitkyina market, F. Fang and A. Roos, March 1997.

Paratypes (all from Myanmar, Kachin State, Myitkyina market). CAS 218070 (1, 125 mm SL) ; NRM 40701 (1, 135 mm SL), S. Kullander and R. Britz, 24 March 1998 . USNM 344653 (6, 116-154 mm SL), C. Ferraris, D. Catania, and Myint Pe, April, 1996 .

Diagnosis. A species of Clupisoma in which the pectoral spine does not reach past the base of the pelvic fin, the abdomen is keeled only from a vertical through the pelvic-fin origin to the anus, pectoral fin with a spine and 11 segmented rays, anal fin with 4 or 5 unbranched, and 43-50 branched rays, and first gill arch with fewer than 18 rakers on the outer face. The body is silvery or white below the lateral line posterior of the pectoral fin, and steel gray above; more anteriorly, the grayish region extends to level of the pectoralfin origin.

Description. (based primarily on the holotype) Body elongate, compressed; depth at dorsal origin about 4 1/2 in SL and slightly larger than HL. Dorsal profile of body nearly horizontal past dorsal fin, straight between dorsal-fin origin and snout; abdomen rounded anteriorly, indistinct midventral keel extends from level of pelvic-fin origin to vent; vent located at anal-fin origin. Lateral line complete, with short branches extending obliquely above and below for entire length. Vertebral column with 45 to 47 vertebrae and 11 or 12 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 broadly 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 approximately that of internarial distance.

Eye lateral, visible from both dorsal and ventral view; eye positioned somewhat below middle of head, middle of pupil at level of anterior nostril; eye covered laterally with adipose tissue, but with ovoid, vertically elongated opening lateral to pupil.

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; upper jaw teeth exposed when mouth is closed. Margin of lower jaw strongly curved, smoothly rounded across symphysis; 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 a slender oblique band that extends nearly to midline, at least in larger specimens; teeth conical, smaller than those of premaxilla. Teeth in three irregular rows laterally, reduced to one near midline. Accessory tooth patches absent from upper jaw and palate.

Gill rakers: 15 to 17 on outer face of first arch (4 or 5* on upper limb and 11* or 12 on lower limb).

Barbel in four pairs, all barbels rest in shallow groove in skin, at least basally. Nasal barbel small, thread-like, extending from lateral margin of posterior naris to level of pupil. Maxillary barbel extends from posterior of anterior naris to level of pectoral-spine tip; 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 one-third of SL, fin base short, about equal to snout length; fin similar in size to pectoral fin; segmented rays preceded by spinelet and sharply pointed spine; 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 about one-half that of first. Dorsal-fin rays: II, 7*. Adipose fin small, located above posterior third of anal-fin base.

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

Anal-fin origin located just anterior to level of middle of SL; anal-fin base long, about 2 1/2 times in SL; fin margin slightly concave anteriorly, nearly straight posteriorly; posterior rays shortest. Last ray without membranous connection to caudal peduncle. Anal-fin rays: iv-v, 43-50 (holotype: iv, 47*).

Pelvic fin small, its length only slightly more than one-half that of pectoral fin; fin origin just posterior to level of posterior insertion of dorsal fin; adpressed fin not extending to anal-fin origin. Pelvic-fin rays: i, 5*.

Pectoral fin triangular, first branched ray longest; adpressed fin extends to below posterior half of dorsal fin base, usually falling short of pelvic-fin origin and never extending beyond. Pectoral-fin spine slender with fine roughened ridge anteriorly and with fine retrorse serrations on distal half of posterior margin. Pectoral-fin rays: I,11*.

Coloration. Body steel gray above, whitish or silvery below. Posterior of dorsal-fin base, gray area restricted to area dorsal to lateral line, more anteriorly, gray extends ventrally to level of pectoral fin. Head dark dorsally, silvery postorbitally and on opercle below level of pectoral spine; snout margin pale. Ventral surface of head and abdomen pale. Dorsal fin pale basally, with diffuse broad marginal band. Adipose fin pale. Caudal fin mostly pale, principal unbranched rays dusky, and margin of fin with broad dark 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. This species is known only from specimens found in the Myitkyina market. Fishes that supply the Myitkyina market come only from the upper reaches of the Irrawaddy River (U Tun Shwe, personal communication). The species appears to be collected by local fishermen routinely, but not in great numbers, inasmuch as specimens were routinely obtained by ichthyologists who visited the Myitkyina market in the late 1990's. Collections made further down river in the Irrawaddy basin, including Mandalay, NyaungU, and the Shweli River mouth, did not include any specimens of this species, but did include specimens of its congener, Clupisoma prateri .

Remarks. Clupisoma roosae is readily distinguished from its congeners. It differs from Clupisoma prateri Hora , the only other congener in Myanmar, by its comparatively short abdominal keel, which extends only between the level of the pelvic fin origin and the vent. More anteriorly, the ventral margin of the abdomen is distinctly rounded. In contrast, the keel of C. prateri extends for most of the length of the abdomen. The two species can also be distinguished on body coloration. C. prateri is nearly uniformly silvery, with a greenish cast along the dorsal midline. In C. roosae , the posterior portion of the body is silvery or white below the lateral line and steel gray above. The two species can be further distinguished by a series of meristic differences that are summarized in Table 1.

Clupisoma garua (Hamilton, 1822) , from the Gangetic region of India and Bangladesh, can be distinguished from Clupisoma roosae in having substantially fewer branched anal-fin rays (fewer than 33 in C. garua , vs. more than 43 in C. roosae ), as well as lacking an adipose dorsal fin, which is present in the new species.

Hora (1937) described Clupisoma montana from the Teesta River, India, and Mirza and Awan (1973) described Clupisoma naziri from the Indus River basin, Pakistan. Datta and Karmakar (1980) distinguished these species from all other species of South Asian Clupisoma by the absence of a midventral keel along the abdomen. Both species also were reported to have fewer total anal-fin ray counts (41 to 43 in C. montana , and 40 to 47 in C. naziri ), than observed in any specimens of C. roosae . In addition, C. montana was observed by Hora to have a short maxillary barbel that is “somewhat longer than head” and, from the illustration of the holotype, does not reach anywhere near the tip of the adpressed pectoral fin as it does in C. roosae .

Clupisoma bastari Datta and Karmakar, 1980 , from the Godavari River basin of Madhya Pradesh, was reported in the original description to have total anal-fin ray counts that range from 52 to 54 rays, which is higher than any counts for C. roosae . In addition, C. bastari was reported to have an abdominal keel that extends from the vent anteriorly onto the thorax, which far exceeds the anterior extent of the keel in C. roosae .

Finally, Ng (1999) recently proposed that Platytropius sinensis Huang, 1981 , a species originally described from the upper Mekong River basin of China, should be placed into Clupisoma . That proposal is supported herein, based on examination of specimens from Laos and Thailand. Clupisoma sinensis is similar to C. roosae , and shares a comparatively low pectoral-fin ray count of 11 branched rays, and comparatively high numbers of branched anal-fin rays (42 to 45 in C. sinensis , 45 to 47 in C. roosae ). However, in both the original description of the species as well as the counts taken from the three specimens examined for this study, C. sinensis exhibits a higher number of gill rakers (20 to 28 in original description, 21 to 23 in examined specimens) than the 15 to 17 found in C. roosae .

Etymology. The species is named for Anna Roos who, together with Fang Fang, both of the Swedish Museum of Natural History, collected the holotype of this species.