Pareuchiloglanis macropterus, Heok Hee Ng, 2004

Heok Hee Ng, 2004, Two new glyptosternine catfishes (Teleostei: Sisoridae) from Vietnam and China., Zootaxa 428, pp. 1-12 : 3-6

Pareuchiloglanis macropterus sp. nov.

(Fig. 1)

Pareuchiloglanis kamengensis (non Jayaram, 1966) - Chu, 1979: 77; Chu, 1986: 41; Chu, 1989: 191, Fig. 3-63; Chu et al., 1990: 205, Fig. 205; He, 1996: 130; Yang, 1998: 307, Fig. 225; Chu & Mo, 1999: 167, Fig. 108 (in part); Ding, 2002: 27 (in part).

Type material. Holotype: ZRC 49124 , 97.5 mm SL; China: Yunnan province, Salween River (Nujiang) drainage; Laowo River, a tributary of Salween River (Nujiang) ca. 5 km to Liuku on Yongping -Liuku road , 25°50'18.6"N 98°53'46.8"E, 900 m asl ; Y.-X. Cai & H. H. Tan, 27 May 2000.

Paratypes. BMNH 1987.9.17.31-32 (2), 157.5-176.0 mm SL; China: Yunnan province, Lushui County, Gulang , 26°5'N 98°36'E; collector unknown, 1974. UMMZ 232108 (2), 61.5-62.2 mm SL; China: Yunnan province, Lushui County, river at Pianma , 26°1'N 98°38'E; collector and date unknown.

Diagnosis. Pareuchiloglanis macropterus can be distinguished from the two other species known from the Salween River (Nujiang) and Irrawaddy River drainages as follows: from P. feae in having a longer adipose-fin base (31.8-37.0% SL vs. 24.1-25.8) with the adipose fin being separate from (vs. confluent with) the caudal fin, and from P. gongshanensis in having a deeper caudal peduncle (2.4-3.0 times in caudal peduncle length vs. 4.0-4.6). It differs from P. kamengensis (with which it was previously identified) in having a shorter prepelvic length (37.0-42.2% SL vs. 53.2-64.9), a longer adipose fin (dorsal-fin base 3.3-3.5 times in adipose-fin base vs. 2.3-3.2), narrower interorbital (24.6-30.2% HL vs. 30.6-40.0), and the presence (vs. absence) of pale patches on the body.

With regard to the remaining congeners, P. macropterus can be distinguished from P. anteanalis in having more vertebrae (41-42 vs. 39-40), a shorter (17.6-20.0% SL vs. 21.7-27.0) and deeper (2.4-3.0 times in caudal peduncle length vs. 4.4-5.9) caudal peduncle, and from P. gracilicaudata and P. longicauda in having a deeper caudal peduncle (2.4-3.0 times in caudal peduncle length vs. 4.1-6.6). It further differs from P. gracilicaudata in having the posterior base of the adipose fin notched (vs. without a notch) and from P. longicauda in having a more restricted gill opening (reaching to the level of the third or fourth pectoral-fin element ventrally vs. to the base of the first pectoral fin element).

Pareuchiloglanis macropterus can be distinguished from P. macrotrema in having a deeper caudal peduncle (6.8-7.4% SL vs. 5.1-5.2), from P. myzostoma in having a more slender body (9.5-12.6% SL vs. 16.7-18.5), and from P. nebulifer in having a longer adipose-fin base (31.8-37.0% SL vs. 28.3-30.9) and a longer snout (50.3-56.5% HL vs. 47.8-50.7). It differs from P. poilanei in having a longer (17.6-20.0% SL vs. 13.0) and more slender (6.8-7.4% SL vs. 8.6) caudal peduncle and the adipose fin separate from (vs. confluent with) the caudal fin, and from P. robusta in having a more slender body (9.5- 12.6% SL vs. 13.3-16.7), more vertebrae (41-42 vs. 37-38), and the pectoral fin reaching to (vs. not reaching) pelvic-fin origin. It can be distinguished from P. sichuanensis in having a more slender caudal peduncle (6.8-7.4% SL vs. 7.8-11.4), more vertebrae (41-42 vs. 35-36) and the adipose fin separate from (vs. confluent with) the caudal fin, and from P. sinensis in having a more slender body (9.5-12.6% SL vs. 14.9-18.6) and caudal peduncle (6.8-7.4% SL vs. 8.1-9.3), a more restricted gill opening (reaching to the level of the third or fourth pectoral-fin element ventrally vs. to the base of the first pectoral fin element), and the pectoral fin reaching to (vs. not reaching) pelvic-fin origin.

Description. Morphometric data as in Table 1. Head and abdominal region moderately broad and strongly depressed. Dorsal profile rising gently from tip of snout to origin of dorsal fin, then almost horizontal or sloping very gently ventrally to end of caudal peduncle. Ventral profile horizontal to anal-fin base, then sloping very gently dorsally to end of caudal peduncle. Caudal peduncle short, moderately deep and compressed. Anus and urogenital openings located approximately midway between posteriormost extent of pelvic fin and base of first anal-fin ray element. Skin smooth. Lateral line complete and midlateral. Vertebrae 24+17=41 (2), 25+16=41 (1), 25+17=42 (1) or 26+16=42 (1) (26+16 in holotype).

Head broadly rounded when viewed from above. Gill openings moderate, extending from posttemporal region to base of third or fourth pectoral-fin element. Branchiostegal rays 4 (3) or 5 (2) (4 in holotype). Head covered with thick skin. Ventral surface of head and thorax covered with papillae, especially in larger specimens.

Barbels extremely flattened and in four pairs. Maxillary barbel with thin flap of skin fringing posterior margin and pointed tip; ventral surface with numerous plicae. Barbel extending just beyond base of first pectoral-fin element. Nasal barbel with small flap of thin skin fringing posterior margin and extending to middle of orbit. Inner mandibularbarbel origin close to midline, extending to midway between lower lip margin and first pectoral-fin element. Outer mandibular barbel originates posterolateral of inner mandibular barbel, extending nearly to first pectoral-fin element. Eye small and almost rounded, subcutaneous and located on dorsal surface of head.

Mouth inferior, with broad, thin papillate lips. Rictal lobe large and papillate. Premaxillary tooth band not exposed when mouth is closed. Oral teeth long, thin and somewhat rounded at tip; in irregular rows on all tooth-bearing surfaces. Premaxillary tooth band broad and of equal width throughout, with a small median indentation. Dentary teeth in two well-separated, roughly triangular patches.

Dorsal fin located at point through anterior third of body. Fin without spine, bearing i,6 (5) rays, and fin margin straight. Adipose fin with long base extending for at least two thirds of postdorsal distance. Fin margin almost straight for entire length; posterior base deeply incised. Caudal fin emarginate, with i,7,6,i (5) principal rays; procurrent rays symmetrical and extend only slightly anterior to fin base.

Anal fin with short base extending approximately one-third of adipose fin-base length, with ii,3 (3) or ii,4 (2) rays (ii,4 in holotype). Fin margin almost straight. Pelvic-fin origin at vertical through posterior end of dorsal-fin base. Pelvic fin greatly enlarged and with broadly rounded margin, first element broadened and with regular striae on ventral surface; with i,5 (5) rays. Pectoral fin greatly enlarged and with broadly rounded margin, first element broadened and with regular striae on ventral surface; with i, 14 (3) or i,15 (2) rays (i,15 in holotype).

Coloration. Light brown on dorsal and lateral surfaces of head and body, light yellow on ventral region. Dorsal surfaces of head and body with series of small light yellow patches: two ovoid patches on occipital region, one on base of first dorsal-fin ray, two on each side of base of last dorsal-fin ray, an elliptical patch on anterior base of adipose fin and another on base of caudal fin. Dorsal fin hyaline, with a thin light brown band near distal margin of fin. Adipose fin light brown, with lighter color around distal edge. Caudal fin brown at base, with a crescentic light-yellow band on middle third of fin. Anal fin hyaline. Dorsal surfaces of pectoral and pelvic fins brown, ventral surfaces light yellow. Maxillary and nasal barbels brown dorsally and light yellow ventrally.

Distribution. Known from the Salween River (Nujiang) and Irrawaddy River drainages in southern China (Fig. 2). The specimens of P. kamengensis from the Mekong River (Lancanjiang) drainage (e.g. by Chu et al., 1990) require study as to whether or not they might be referable to P. macropterus .

Etymology. From the Greek makros, meaning large, and pteron, meaning fin, in reference to the long-based adipose fin of this species. Used as an adjective.