Trimma fangi Winterbottom & Chen, 2004

Winterbottom, Richard & Hoese, Douglass F., 2015, A revision of the Australian species of Trimma (Actinopterygii, Gobiidae), with descriptions of six new species and redescriptions of twenty-three valid species, Zootaxa 3934 (1), pp. 1-102 : 28-30

Trimma fangi Winterbottom & Chen, 2004

Spot-faced Pygmygoby

Figs. 12–13 , Pl. 1 F

Trimma fangi Winterbottom & Chen, 2004:105 ( Pulau Bajau, Anambas, South China Sea); Allen & Erdmann, 2012:937 ( Indonesia and Philippines).

Trimma sp. 2: Kimura & Matsuura, 2003:193 (Bitung, N. Sulawesi).

Australian Material. Queensland: Lizard Id: AMS I.20730-014, 12(10–24), 20–22 m; AMS I.21586-002, (17), 5–6 m; AMS I.25066-013, 8(18–24), 20 m. Timor Sea: Cartier Reef: NTM S-13416-007, (12). Western Australia: Cassini Id: WAM P. 31653.014, (26), 25– 30 m.

Other material. In addition to the type material, we have examined specimens in the following collections: Indonesia: Ambon: USNM; WAM. Ceram ( Moluccas): USNM. Sulawesi: BPBM; USNM. North Central Java: USNM. Raja Ampat: ROM. Palau: BPBM. Papua New Guinea: Hermit Ids: ROM; USNM. Jalun Id: USNM. Milne Bay District: USNM. Nagada Harbour: CAS. Tset Id: USNM. New Britain: ROM; USNM. Philippines: Apo Id: AMS. Solomons: Florida Id: AMS; USNM.

Diagnosis. A species of Trimma with a concave bony interorbital about half pupil-diameter in width; no scales on the predorsal midline, cheeks or opercles; fifth pelvic-fin ray branched twice dichotomously and about 80% the length of the fourth; no trough or groove posterodorsal to the eye; epaxialis musculature reaching anterior to above the posterior margin of the pupil; second spine of first dorsal fin somewhat elongated and may reach posteriorly as far as the base of the sixth dorsal-fin ray; light (red in life) spots on the cheek and nape; anterior extent of scales only just exceeding the upper gill opening, immediately above which is a dark, half pupil-diameter spot; pectoralfin base and branchiostegal region frequently with diffuse dark mottlings and spots.

Description. The description is primarily based on the 20 specimens from ROM 60559 (10 male, 10 female) from the Hermit Islands, PNG. Dorsal fin VI + I 9 (once I 8), second spine longest, reaching to between bases of first to sixth dorsal-fin rays when adpressed, first ray of dorsal fin usually branched, anterior element of last element branched; anal fin I 8, first ray unbranched, anterior element of last ray branched; pectoral fin 17–18 (mean = 17.8), reaching posteriorly to a vertical in line with anal spine, usually upper- and lower-most four rays unbranched with remaining rays branched; pelvic fin I 5, first four rays with between 1 and 3 sequential branches, fifth ray with two dichotomous branches (four terminal tips), 60–80% length of fourth ray, which reaches posteriorly to anterior few elements of anal fin; fraenum absent, basal membrane equal to fifth ray. Lateral scales 23 (occasional specimens with an additional small scale anteriorly beneath pectoral-fin base); transverse scales 8; scales on pectoral-fin base, breast, and anterior midline of belly cycloid, remaining scales ctenoid; body scales extending anteriorly to a line between anterodorsal margin of gill opening and origin of first dorsal fin (usually not extending anterior to dark scapular spot); four vertical rows of scales on pectoral-fin base; no scales on the head or nape. Teeth in outer and inner rows of both jaws of enlarged, curved, spaced canines, those in inner rows about two-thirds size of outer row teeth, several irregular rows of small, straight, conical teeth between inner and outer rows. Tongue pointed to sharply rounded, about two-thirds pupil diameter in width. Gill opening to below midpupil; outer gill rakers on first arch 3–5 + 14–15 (mean = 3.9 + 14.5). Anterior nares in a short tube; posterior nares pore-like with a raised rim; nasal sac slightly elevated and confined to anterior half of snout. Interorbital trough moderate, posterodorsal trough absent; bony interorbital width about half pupil diameter; epaxialis musculature reaching to a point just anterior to a vertical with posterior margin of pupil. Vertebral pattern is Type B.

Colour pattern. Live and freshly collected. Living specimen photographed on Great Barrier Reef (Pl. 1.F) has ground colour of translucent dark purple with three diffuse yellow to reddish-orange stripes (some parts as rows of spots) along midlateral septum and along second scale rows dorsal and ventral to this, with other, similarlycoloured, scattered spots and short lines; scale pockets thinly outlined with brown chromatophores and melanophores; almost eye-diameter, diffuse dark blotch on upper peduncle just anterior to dorsal caudal-fin rays; dark, half-pupil diameter spot immediately above posterodorsal edge of gill opening; nape with a few spots about pupil-diameter in width and figure-of-eight shaped yellow blotch posterodorsal to eye with its longitudinal axis about 20° to horizontal; orange, pupil-diameter sized spot immediately behind middle of eye; cheek and opercle with three roughly oblique lines of yellow (cheek) to red (opercle) approximately pupil diameter spots and blotches; five yellow to red spots invested with brown chromatophores on branchiostegal membrane along posterior margin of opercular membrane, first just below dark spot on shoulder above gill opening, second small and faint, fifth below vertical with posterior margin of eye; two similar spots on pectoral-fin base and similar spot below this just anterior to pelvic-fin origin; oblique yellow stripe from mid-cheek below anterior half of pupil passing anteroventrally onto chin across posterior margins of jaws; snout orange-yellow; iris mottled with red, orange, yellow and brown chromatophores; spinous dorsal fin with basal row of half-pupil diameter orange spots; second dorsal and anal fins with irregular rows of one-third pupil diameter orange spots; caudal fin with scattered, similar sized orange spots; pectoral and pelvic fins hyaline although bases of pelvic rays suffused with orangeyellow. Underwater photograph of a specimen from New Britain has much darker body, and scale pockets more strongly outlined. Specimen from Cassini Island (26 mm SL), Western Australia ( Fig. 13 A) apparently photographed some time after collection, has much darker body; however, patterns described above still discernible, although caudal blotch absent (as in all other specimens we have examined). Two freshly collected specimens from Raja Ampat, Indonesia (see Fig. 13 B) with lighter background colour with up to five irregular stripes of light orange spots at posterior margins of scales; oblique yellow ovoid spot on nape behind eye, coalescence of spots in posterior oblique cheek row into stripe across angle of preopercle; and spots below eye and snout red (especially ventrally) rather than yellow or orange. Live specimen appears to lack red stripes across fleshy interorbital present in other specimens. In freshly collected holotype (Anambas Island, Indonesia), ovoid blotch on nape joined ventrally to spot behind middle of eye to form roughly ‘U’-shaped marking ( Winterbottom & Chen, 2004, Fig. 2 ).

Preserved. Similar, but orange areas appear unpigmented against background of small, regularly scattered brown chromatophores and melanophores.

Etymology. The species was named after Prof. Lee-Shing Fang, head of the Museum of Marine Biology and Aquarium, Pintung, Taiwan.

Distribution. We have examined material from western Java east to Palau and south to the Solomon Islands, the Great Barrier Reef and off North-west Australia ( Fig. 12 ).

Comparisons. There are four species of Trimma with an unscaled predorsal midline, outlined scale pockets and a well-defined, dark, half-pupil diameter spot immediately above the dorsal margin of the gill opening. Trimma sheppardi Winterbottom, 1984 , usually has two such spots horizontally aligned, pale bars on the cheek, fifth pelvic-fin ray branched once, and fleshy median ridges just anterior to the first dorsal-fin origin and in the interorbital region. The ranges of the other two species overlap that of T. fangi . In both species the sides of the nape are scaled anteriorly almost to the orbit, and the second dorsal spine does not reach beyond the base of the spine of the second dorsal fin when adpressed. Trimma stobbsi has an unbranched fifth pelvic-fin ray that is about 50% the length of the fourth, a light brown colouration, and uniform cheek pigmentation. Trimma agrena Winterbottom and Chen, 2004 has a rather similar colour pattern to T. fangi , but the spots and blotches on the head are smaller (about half pupil diameter), contain scattered melanophores and brown chromatophores, and the anterior pair of vertically aligned dark spots on the pectoral-fin base is absent.

The BOL results for CO1 from 10 specimens from Raja Ampat ( Indonesia, n = 5), Rabaul (New Britain, n = 3), and Lizard Island (Great Barrier Reef, n = 2) suggest that there are two haplogroups in this material, separated by 3.5% sequence divergence ( Winterbottom et al., 2014). The Rabaul and Lizard Island material form one of these groups, the Raja Ampat material constitutes the second group. We currently lack tissues for specimens from other areas, including the type locality (Anambas Islands, South China Sea), and thus it is unclear which haplogroup (if either) the type material belongs. Furthermore, we lack samples for genetic examination from both Western Australia and the Timor Sea, and so cannot vouch that they represent the same haplogroup that is present on the Great Barrier Reef. The use of the name T. fangi for the Australian material is therefore provisional.

Discussion. This species has been referred to informally as Trimma DFH sp. 20 or Trimma RW sp. 65, and is known from depths of 1– 34 m.

Figures

FIGURE 2. Trimma anaima, A: 13.7 mm SL male, ROM 83022; B: 14.0 mm SL male, ROM 80303 (note parasitic copepod attached to belly), both from Palau. Photos by R. Winterbottom.

FIGURE 12. Map of the distributions of Trimma emeryi (solid inverted triangles) and T. fangi (solid pentagons). A solid circle with a white star indicates localities at which both species occur.

FIGURE 13. Trimma fangi. A: 26 mm SL, WAM P. 31653.014, Cassini Ids, Western Australia. B: 24.1 male, ROM 85083, Mutus Id, Raja Ampat. Photos by G. R. Allen (A) and R. Winterbottom (B).