Gymnochanda verae, Tan, Heok Hui & Lim, Kelvin K. P., 2011

Tan, Heok Hui & Lim, Kelvin K. P., 2011, A new species of glass-perch from Belitung Island, Indonesia (Teleostei: Ambassidae: Gymnochanda), Zootaxa 3085, pp. 55-62 : 56-60

Gymnochanda verae , new species

( Figs. 1 a–b, 2a–b, 3)

Material examined. All specimens from the Gantung area of Pulau Belitung, Indonesia. MZB 17200, holotype, 21.4 mm SL male; P. Yap, 2 Aug.2011 ― MZB 17201, 3 paratypes (1 male, 2 females), 19.2–22.3 mm SL; P. Yap, 2 Aug 2011 ― ZRC 53122, 30 paratypes (15 males, 15 females); P. Yap, 2 Aug.2011 ― CMK 22378, 7 paratypes (4 males, 3 females), 16.3–25.3 mm SL; Belitung Island: Gantung area; P. Yap, 11 Aug.2011.

Diagnosis. Gymnochanda verae can be differentiated from its congeners by the following characters: mature males with expanded anal and second dorsal fins, the soft rays of both fins extending to midway of the caudal fin, forming a triangular profile; the highly elongated rays of the anal and second dorsal fins joined throughout their length by the interradial membrane; up to half of the distal part of both the anal and the second dorsal fins carmine red in life (hyaline when preserved); distal half of both upper and lower caudal-fin lobes carmine red in life (hyaline when preserved); female without any elongated fin rays or colour. Gymnochanda verae also differs from its congeners apparently in having more serrae on its head: supraorbital ridge with 7 anterior serrae (vs. 0–5 anterior spines in the other species), preorbital ridge with 3 serrae (vs. 4 in G. f l a m e a and 2 in G. limi ); preopercular ridge with 7 serrae (vs. 1–4 in the other species); interopercle with 2 serrae (vs. none in G. limi and G. flamea ); hind margin of preopercle with up to 9 serrae (vs. 1–5 in the other species). Information on head serrations on G. filamentosa are from Fraser-Brunner (1954: 210) and Boeseman (1957: 76), and on G. l i m i from Kottelat (1995: 56).

Description. See Table 1 for morphometric data. Body compressed, ovoid, with a pointed head, deepest at second dorsal-fin origin. Top of head with a concave slope, forming a slight hump before origin of first dorsal fin. First dorsal-fin base with concave profile. Base of second dorsal fin with convex profile. Ventrum with convex profile peaking at anal-fin origin. Body tapering to its narrowest at caudal peduncle. Scales absent. Lateral groove complete but indistinct.

Mouth small, lower jaw included when closed. Teeth in upper jaw in a single row laterally, in two rows near symphysis. Teeth in lower jaw in a narrow band. Gill rakers long, slender, 12 on lower arm of first branchial arch (based on holotype).

Preorbital ridge with three strong, backward oriented spines. Preorbital edge with up to 5 (maximal) strong serrae. Preoperculum with 6 serrae along lower edge, a large one at its angle, with up to 9 blunt serrae along its posterior margin. Preopercular ridge with 7 serrae. Supraorbital ridge with up to 7 small serrae anteriorly, 2 broad serrae posteriorly. Suborbital bones entire. Interopercle with 2 serrae at its posterior angle. Margin of opercle smooth except for 2 or 3 low, broad serrae on lower edge ( Fig. 3 ).

First dorsal fin origin just posterior to pelvic-fin origin, with 7 spines, relatively tall, when adpressed touching base of third or fourth branched ray of second dorsal fin, second spine longest, more than twice length of first spine; third spine about ¾ length of second spine; spines 6 and 7 much reduced. Second-dorsal fin origin just posterior to anal-fin origin, with 1 spine and 12–13 branched rays, linked to first dorsal fin by a very low membrane. Anal-fin origin directly opposite the base of the sixth spine of first dorsal fin, with 3 spines and 12–13 branched rays. Pelvic fin short, with 1 simple and 5 branched rays, its origin at about halfway of pectoral-fin base, not touching anal-fin origin when adpressed. Pectoral fin with 12 rays. Caudal fin with 8–9+8 principal rays.

Male: Second dorsal fin with 1 spine and 13 branched rays, spine about same length as third spine of first dorsal fin, branched rays 4 to 6 longest, adpressed fin reaching to middle of caudal fin. Anal fin with 3 spines and 13 branched rays, branched rays 4 to 6 longest, adpressed fin reaching middle of caudal fin. Distal margins of second dorsal and anal fins concave. In lateral profile, extended dorsal fin and anal fin form a triangular shape individually.

Female: Second dorsal fin with one spine and 12 branched rays, spine about same length as anterior half of branched rays. Anal fin with 3 spines and 12 branched rays, spines about same length as anterior half of branched rays.

Vertebrae 26–27. Largest specimen recorded 25.3 mm SL (male).

Colouration in life ( Fig. 1 ). Male: Head with yellow and black pigmentation concentrated around lips and snout. Eye with black pigmentation on dorsal margin. Region above and posterior to eye silvery-gold. Body translucent, suffused with tiny yellow chromatophores, its posterior half with up to 10 narrow complete or interrupted black bars; with dorsal and anal-fin osteological processes visible, vertebral column discernible, hypural plate visible; abdominal cavity covered with silver-white membrane, large translucent air bladder visible directly above abdominal membrane. First dorsal fin hyaline with some yellow and black pigmentation. Second dorsal fin with basal inter-radial membranes suffused with yellow pigmentation, posterior half of branched fin-rays and interradial membrane carmine red, distal part of posterior rays with narrow white margin. Anal fin with black pigments anteriorly, basal interradial membranes suffused with yellow pigmentation, posterior half of branched rays and interradial membrane carmine red. Distal part of upper and lower lobes of caudal fin carmine red, the remaining parts hyaline. Pelvic and pectoral fins hyaline.

Female: Colouration as above, except all fins mainly hyaline; a yellow tinge on dorsal fins and on body.

Colouration in ethanol ( Fig. 2 ). Both male and female: Life colours largely not retained. Region above and posterior to eye with black blotch. Body opaque white, with scattered melanophores; a yellowish tinge on dorsum. Second dorsal, anal and caudal fins with faint reddish margins (colourless in longer-preserved specimens).

Distribution. Gymnochanda verae is currently known only from the Gantung area in the eastern part of Pulau Belitung, a large Indonesian island at the northwestern corner of the Java Sea, between the islands of Sumatra and Borneo.

Etymology. Named for Vera Kasim, wife of our good friend and fish exporter Gunawan Kasim, in appreciation of her generous assistance and logistic support.

Figures

FIGURE 1. Gymnochanda verae. a. male ca 23 mm SL, living specimen, not preserved; b. female ca 19 mm SL, living specimen, not preserved.

FIGURE 2. Gymnochanda verae. a. MZB 17200, 21.4 mm SL male, holotype; b. MZB 17201, 19.2 mm SL female, paratype.

FIGURE 3. Line drawing of head of Gymnochanda verae. MZB 17200, 21.4 mm SL male holotype, showing head serration. Scale bar = 1 mm.