Glyptothorax longinema, LI, 1984

Jiang, Wansheng, Ng, Heok Hee, Yang, Junxing & Chen, Xiaoyong, 2012, A taxonomic review of the catfish identified as Glyptothorax zanaensis (Teleostei: Siluriformes: Sisoridae), with the descriptions of two new species, Zoological Journal of the Linnean Society 165 (2), pp. 363-389 : 373-377

GLYPTOTHORAX LONGINEMA LI, 1984 ( FIG. 8 )

Glyptothorax longinema Li, 1984: 81 , fig. 6 (type locality: Liuku, Yunnan, Nujiang drainage).

Glyptothorax rubermentus Li, 1984: 83 , fig. 8 (type locality: Baoshan, Yunnan, Lancangjiang drainage).

Glyptothorax zanaensis Wu & Wu, 1992: 532 , fig. 146.

Glyptothorax zainaensis (non Wu, He & Chu) Chu, Mo & Kuang, 1990: 187 (in part); Yang, 1998: 298, fig. 217; Chu & Mo, 1999: 146 (in part).

Material examined: Nujiang drainage: KIZ 741097 (holotype), 67.0 mm SL; KIZ 740198–740200 (three paratypes), 55.1–58.9 mm SL; China: Yunnan , Nujiang Prefecture, Lushui County, Liuku Township , Bijiang. KIZ 1981001381–1981001383 (3), 82.3– 89.1 mm SL; China: Yunnan , Nujiang Prefecture, Lushui County. KIZ 2006000865 (1), 87.8 mm SL; KIZ 2006000870 (1), 95.2 mm SL; KIZ 2006000878 (1), 89.0 mm SL; China: Yunnan , Baoshan Prefecture, Longlin County, Sanjiangkou. KIZ 2002002337– 2002002341 (5), 71.8–91.0 mm SL; China: Yunnan , Lincang Prefecture, Yongde County, Nanting River . CAS 223290 (1), 75.6 mm SL; CAS 229924 (6), 37.8– 67.9 mm SL; China: Yunnan , Mangyin River , from mouth upstream c. 250 m to point c. 100 m downstream of bridge, 24°24′55.4″N, 98°58′35.3″E. CAS 226099 (5), 58.3–72.7 mm SL; China: Yunnan , Baoshan Prefecture, Longling County, Gongyang River from mouth at confluence of Nujiang ( Salween River ) upstream c. 400 m, 24°10′41.1′N, 98°54′12.5′E. CAS 223055 (3), 36.4–39.2 mm SL; China: Yunnan ,

SL, standard length; PDL, predorsal length; PAL, preanal length; PVL, prepelvic length; PPL, prepectoral length; LDFB, length of dorsal-fin base; DSL, dorsal-spine length; LAFB, length of anal-fin base; VFL, pelvic-fin length; PFL, pectoral-fin length; PSL, pectoral-spine length; CFL, caudal-fin length; LAdFB, length of adipose-fin base; DAD, dorsal to adipose distance; PAD, post-adipose distance; LCP, length of caudal peduncle; DCP, depth of caudal peduncle; BDA, body depth at anus; HL, head length; HW, head width; HD, head depth; AAL, adhesive apparatus length; AAW, adhesive apparatus width; SnL, snout length; IOD, interorbital distance; ED, eye diameter; NBL, nasal barbel length; MBL, maxillary barbel length; IMBL, inner mandibular barbel length; OMBL, outer mandibular barbel length.

Baoshan Prefecture, Longling County, Taozhai River from its mouth at Nujiang (Salween River) to a point c. 300 m upstream from road bridge, 24°13″N, 99°1″E. ZRC 50712 (4), 77.2–94.6 mm SL; China: Yunnan, Nujiang at Daojie, west of Baoshan , 25°0″N, 98°53″E .

Lancangjiang drainage: KIZ 749356 (holotype of G. rubermentus ), 90.3 mm SL; KIZ 749357–749359 (three paratypes of G. rubermentus ), 64–86 mm SL; China: Yunnan, Baoshan Prefecture, Wayao Township . KIZ 2005000592 (1), 115.1 mm SL ; China: Yunnan, Diqin Prefecture , Deqin County, Gushui. KIZ 74884 (1), 67.7 mm SL ; China: Yunnan, Diqin Prefecture, Weixi County, Baijixun. KIZ 1977001502 (1), 71.2 mm SL; KIZ 1977001505–1977001506 (3), 64.6– 73 mm SL ; China: Yunnan, Nujiang Prefecture , Lanping County. KIZ 1978000845 (1), 94.5 mm SL; KIZ 1978000847 (1), 79.5 mm SL; KIZ 1978000849 (1), 90.8 mm SL ; China: Yunnan, Lincang Prefecture , Yun County. KIZ 1976003603–1976003604 (2), 73.5– 110 mm SL ; China: Yunnan, Dali Prefecture, Yangbi County .

Diagnosis: Glyptothorax longinema can be distinguished from other congeners in the upper Irrawaddy, Mekong, and Salween River drainages with a uniformly dark-coloured body in having a thoracic adhesive apparatus consisting of striae arranged in a broad oval field (in a somewhat cardiform shape vs. a more elongate, ovoid field in other congeners; Fig. 5 ). It further differs from G. burmanicus in having the depressed area in the thoracic adhesive apparatus not wholly enclosed by ridges (vs. ridges of the thoracic adhesive apparatus enclosing an ovoid depressed region in the centre) and a shorter head (22.7–27.7% SL vs. 27.6–30.8); from G. deqinensis in having more serrations on the posterior edge of the pectoral spine (ten to 12 vs. five to eight); from G. fucatus in having a uniformly coloured lateral surface of the body (vs. becoming paler ventrally immediately under lateral line) and a triangular anterior nuchal plate element without (vs. with) extensive contact with the posterior nuchal plate element ( Fig. 6 ); and from G. granosus in having a triangular anterior nuchal plate element without (vs. with) extensive contact with the posterior nuchal plate element ( Fig. 7 ), a deeper caudal peduncle (7.1–10.6% SL vs. 5.7–7.6), and a wider head (19.3–22.9% SL vs. 16.6–19.5). Glyptothorax longinema is further distinguished from G. longicauda in having shorter post-adipose distance (14.2– 18.2% SL vs. 18.2–23.0) and longer nasal barbel (27.6–49.4% HL vs. 16.1–23.8), from G. longjiangensis in having small, conical tubercles (vs. large plaques bearing unculiferous ridges) on the dorsal surface of the head and longer nasal barbel (27.6–49.4% HL vs. 18.1–27.9), from G. macromaculatus in having distally expanded (vs. pointed) neural spines, without (vs. with) a diverging pattern of striae running along the edges of the median depression in the thoracic adhesive apparatus and a shorter head (22.7–27.7% SL vs. 27.4–34.4), and from G. minimaculatus in lacking (vs. having) dark spots on the body and longer nasal barbel (27.6–49.4% HL vs. 18.3–26.2). It further differs from G. ngapang in having longer adipose-fin base (13.1–17.8% SL vs. 10.7–14.0), deeper caudal peduncle (7.1–10.6% SL vs. 5.3–7.4), and wider head (19.3–22.9% SL vs. 15.8–19.7), from G. obliquimaculatus in lacking (vs. having) both the ridges of the thoracic adhesive apparatus extending onto the gular region and irregular dark blotches on the flanks and having a longer adipose-fin base (13.1–17.8% SL vs. 8.6–12.9), and from G. trilineatus in lacking (vs. having) a distinct pale midlateral line on the flank, and from G. zanaensis in lacking (vs. having) a diverging pattern of striae running along the edges of the median depression in the thoracic adhesive apparatus and having a deeper body (depth at anus 14.6–20.4% SL vs. 11.4–15.8) and caudal peduncle (7.1–10.6% SL vs. 5.5–7.9).

Description: Biometric data in Table 4.

Head depressed, body subcylindrical. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, and then sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile flat to anal-fin base, then sloping gently dorsally from analfin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Skin tuberculate, uniformly arranged on sides of body; tubercles particularly distinct along lateral line and in opercular region. Lateral line complete and midlateral, laterosensory pores rimmed in beige. Anterior nuchal plate element triangular, with straight anterolateral margins and without extensive contact with posterior nuchal plate element. Vertebrae 16 + 22 = 38 (3), 16 + 23 = 39 (2), or 17 + 22 = 39 (1).

Head depressed and broad, triangular when viewed laterally. Snout gently convex when viewed from above. Anterior and posterior nares separated only by base of nasal barbel. Eyes small and ovoid, horizontal axis longest, located on dorsal half of head. Gill openings broad, extending from directly beneath posttemporal to isthmus.

Barbels in four pairs. Maxillary barbel long and thick, extending beyond base of last pectoral-fin ray. Nasal barbel slender, extending to middle of orbit. Inner mandibular barbel extending to middle of thoracic adhesive apparatus. Outer mandibular barbel originating posterolateral of inner mandibular barbel, extending to middle of pectoral-fin base.

Mouth inferior, premaxillary tooth band partially exposed when mouth closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary teeth in single crescentic-shaped band. Dentary teeth in two patches separated by narrow gap at midline. Palate edentate.

Dorsal fin slightly further from snout-tip than to adipose-fin origin, with I,6 rays; dorsal margin of fin truncate; anterior margin of spine smooth, posterior margin with weak serrations. Adipose fin straight anteriorly and angular posteriorly. Caudal fin deeply forked, lower lobe slightly longer than upper lobe and with i,7,8,i principal rays. Procurrent rays symmetrical, extending only slightly anterior to fin base and consisting of four to seven rays. Anal-fin origin slightly anterior to vertical through adipose-fin origin. Anal fin with straight anterior margin and straight or slightly concave posterior margin; with ii,8 (5), ii,9 (11), or ii,10 (13) rays. Pectoral fin with I,9 (11) or I,10 (18) rays; posterior fin margin straight; anterior margin of spine smooth, posterior margin with ten to 12 serrations. Pelvic-fin origin posterior to vertical through posterior end of dorsal-fin base. Pelvic fin with slightly convex margin and i,5 rays; tip of adpressed fin not reaching anal-fin origin.

Thoracic adhesive apparatus present, consisting of skin ridges (striae) in an elongate oval field extending from isthmus to posterior half of pectoral-fin base and with median depression present on posterior onethird to half. Striae orientated anterodistally, radiating from median depression.

Coloration: In 75% ethanol: dorsal and lateral surfaces of head and body brown, fading to greyish yellow on long-term preservation. Ventral surfaces of head and body greyish beige. Dorsal surface of neurocranium with indistinct pale blotches; nuchal plate elements distinctly pale. A faint, thin, light grey middorsal stripe outlining distal tips of neural spines extending from base of last dorsal-fin ray to adiposefin origin. Laterosensory pores along lateral line rimmed in beige, imparting appearance of a narrow pale line. Dorsal fin and anal fin with brown bases and dark brown bands on middle third of fins, rest of fin yellow to hyaline. Pectoral and pelvic fins with brown bases and dark brown bands on middle third of fins dorsally, light yellow ventrally. Adipose fin yellow at base and distally, remainder of fin dark brown. Caudal fin brown, with tips of lobes hyaline. Maxillary and nasal barbels brown dorsally, light yellow ventrally.

Distribution: Known from Salween (Nujiang) and Mekong (Lancangjiang) River drainages ( Fig. 7 ).

Remarks: As G. longinema and G. rubermentus are simultaneous subjective synonyms, we use our prerogative as first revisers by designating the priority of G. longinema over G. rubermentus in accordance with Article 24.2 of the International Code of Zoological Nomenclature ( ICZN, 1999).

Figures

Figure 5. Thoracic adhesive apparatus of: A, Glyptothorax zanaensis, KIZ 2000000534, 60.1 mm SL; B, Glyptothorax longinema, KIZ 740197, 67 mm SL; C, Glyptothorax fucatus sp. nov., KIZ 20050410936, 72.9 mm SL, D, Glyptothorax granosus sp. nov., KIZ 2000000534, 61.8 mm SL.

Figure 6. Dorsal view of nuchal plate elements of: A, Glyptothorax zanaensis and Glyptothorax longinema; B, Glyp- tothorax fucatus sp. nov.; and C, Glyptothorax granosus sp. nov.

Figure 7. Distributions of the four species studied; -, Glyptothorax zanaensis; ·, Glyptothorax granosus sp. nov.;, Glyptothorax longinema; •, Glyptothorax fucatus sp. nov.

Figure 8. Glyptothorax longinema. A, KIZ 740197, holotype, 67 mm SL; China: Bijiang; B, KIZ 2000000559, 60.1 mm SL; China: Shangjiang; C, KIZ 749356, holotype of Glyptothorax rubermentus, 90.3 mm SL; China: Wayao. a, dorsal view; b, lateral view; c, ventral view. Scale bars = 10 mm.