Glyptothorax fucatus, Jiang & Ng & Yang & Chen, 2012

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 : 380-382

GLYPTOTHORAX FUCATUS SP. NOV. ( FIG. 10 )

Material examined: Holotype: KIZ 20050410936 (1), 72.9 mm SL; China: Yunnan, Lincang Prefecture, Cangyuan County, Banhong Township , Fugong Village , Fugong River (a tributary of Xiaohei River , which is a tributary of Nanting River , which is itself a tributary to the Nujiang ), 23°19′47.2″N, 99°07′28.3″E, about 963 m asl.; X. Y. Chen, X. F. Pan, G. H. Yu and Z. S. Wang; 10.iv.2005.

Paratypes: KIZ 20050410922–20050410931 (10), 82.1–103.2 mm SL ; KIZ 20050410934 (1), 75.8 mm SL ; KIZ 20050410937–941 (5), 61.5–75.7 mm SL ; KIZ 20050410943 (1), 63.8 mm SL ; KIZ 20050410947 (1), 55.0 mm SL; data as for holotype .

Additional nontype materials: KIZ 200504111477– 200504111484 (8), 64.3–88.3 mm SL; China: Yunnan, Lincang Prefecture, Cangyuan County, Banlao Township , Mengnong River (a tributary of Nangun River , which is itself part of the Salween drainage) .

Diagnosis: Glyptothorax fucatus sp. nov. can be distinguished from other congeners in the upper Irrawaddy, Mekong, and Salween River drainages with the lateral surface of the body ventrally becoming paler immediately below lateral line (vs. lateral surface uniformly coloured, with vertical maculates, or with dark spots). 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), a deeper caudal peduncle (8.2–11.1% SL vs. 6.5–8.7), shorter head (21.7–25.6% SL vs. 27.6–30.8), and larger eye (diameter 8.6–11.7% HL vs. 5.5–9.1); from G. deqinensis in having more serrations on the posterior edge of the pectoral spine (nine to 12 vs. five to eight) and a deeper body (depth at anus 15.5–21.1% SL vs. 13.5– 15.8) and caudal peduncle (8.2–11.1% SL vs. 6.7–8.5); from G. granosus in having a triangular anterior nuchal plate element without (vs. with) saddleshaped lateral expansions of the pterygiophores ( Fig. 6 ), a deeper body (depth at anus 15.5–21.1% SL vs. 12.9–16.5) and caudal peduncle (8.2–11.1% SL vs. 5.7–7.6) and a larger interorbital distance (28.1– 34.0% SL vs. 20.4–28.8); and from G. longicauda in having a shorter postadipose distance (13.5–18.7% SL vs. 18.2–23.0), and deeper body (depth at anus 15.5– 21.1% SL vs. 11.0–16.9) and caudal peduncle (8.2– 11.1% SL vs. 5.7–8.4). It differs from G. longinema in having a triangular anterior nuchal plate element with concave (vs. straight) anterolateral edges with (vs. without) extensive contact with the posterior nuchal plate element ( Fig. 6 ), from G. longjiangensis in having small, conical tubercles (vs. large plaques bearing unculiferous ridges) on the dorsal surface of the head, and deeper caudal peduncle (8.2–11.1% SL vs. 6.9–8.8), 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 shorter head (21.7–25.6% SL vs. 27.4–34.4), and from G. minimaculatus in lacking (vs. having) dark spots on the body, having a triangular anterior nuchal plate element with concave (vs. straight) anterolateral edges with (vs. without) extensive contact with the posterior nuchal plate element, and a deeper caudal peduncle (8.2–11.1% SL vs. 7.4– 7.9). Glyptothorax fucatus is distinguished from G. ngapang in having a deeper body (depth at anus 15.5–21.1% SL vs. 11.2–16.4) and caudal peduncle (8.2–11.1% SL vs. 5.3–7.4), 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 (12.8–16.7% SL vs. 8.6– 12.9), from G. trilineatus in lacking (vs. with) a distinct pale midlateral line on the flank, and having a deeper body (depth at anus 15.5–21.1% SL vs. 10.1– 16.2), and from G. zanaensis in having a triangular anterior nuchal plate element with concave (vs. straight) anterolateral edges with (vs. without) extensive contact with the posterior nuchal plate element ( Fig. 6 ), deeper body (depth at anus 15.5–21.1% SL vs. 11.4–15.8) and caudal peduncle (8.2–11.1% SL vs. 5.5–7.9), larger eye (diameter 8.6–11.7% HL vs. 6.0– 9.2), and shorter nasal and maxillary barbels (length of nasal barbel 25.9–34.5% HL vs. 33.9–52.9; length of maxillary barbel 77.2–109.0% HL vs. 103.8–161.0).

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 granular, with prominent tubercles sparsely distributed on base of adipose and caudal fins. Lateral line complete and midlateral, laterosensory pores rimmed in beige. Anterior nuchal plate element triangular, with concave anterolateral margins and extensive contact with posterior nuchal plate element, but lacking saddle-shaped extensions. Vertebrae 16 + 21 = 37 (10) or 16 + 22 = 38 (6).

Head depressed and broad, triangular when viewed laterally. Snout 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 post-temporal to isthmus.

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

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

Dorsal fin of subequal distance from snout tip to adipose-fin origin, with I,6 rays; dorsal margin truncate; anterior margin of spine smooth, posterior margin with weak serrations. Adipose fin straight anteriorly and angular posteriorly. Caudal fin deeply forked, lobes almost equal, with i,7,7,i (8) or i,7,8,i (16) principal rays. Procurrent rays symmetrical, extending only slightly anterior to fin base and consisting of five to eight 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,9 (7), ii,10 (16), or ii,11 (4) rays. Pectoral fin with I,8 (6), I,9 (20), or I,10 (1) rays; posterior fin margin straight; anterior spine margin smooth, posterior spine margin with nine to 12 serrations. Pelvic-fin origin at 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 end of pectoral-fin base and with median depression present on posterior one-third to half. Striae orientated anterodistally, radiating from median depression.

Coloration: In 75% ethanol: dorsal surface of head and body brown, lateral surfaces of body ventrally becoming paler immediately below lateral line. Ventral surfaces of head and body greyish beige. Dorsal surface of head with distinct pale patches; nuchal plate elements distinctly pale. A distinct, thin, light grey mid-dorsal stripe outlining distal tips of neural spines extending from base of last dorsal-fin ray to adipose-fin origin. Laterosensory pores along lateral line rimmed in beige, imparting appearance of a narrow, pale line. Dorsal and anal fins, and dorsal surfaces of pectoral and pelvic fins with dark brown bases and bands on middle third, rest of fins yellow to hyaline. 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 the Fugong River, a tributary of the Xiaohei River, a tributary of the Nanting River, itself a tributary to the Salween River (Nujiang); and the Mengnong River, a tributary of the Nangun River, itself a tributary to the Salween River ( Fig. 7 ).

Etymology: The specific name fucatus is from the Latin meaning painted or coloured, in reference to the unusual colour pattern of the lateral surfaces of this species.

Figures

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 10. Glyptothorax fucatus, KIZ 20050410936, holotype, 72.9 mm SL, China: Fugong River; A, dorsal view; B, lateral view; C, ventral view. Scale bar = 10 mm.