Trimma flavatrum Hagiwara & Winterbottom, 2007

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 : 31-34

Trimma flavatrum Hagiwara & Winterbottom, 2007

Wasp Pygmygoby

Fig. 14–15 , Pl. 1 G

Trimma flavatrum Hagiwara & Winterbottom, 2007:164 , figs 1–6 (Nishikomi Cave, Amamioshima Id, Nansei Ids, Japan); Allen & Erdmann, 2012:937 (western Pacific)

Australian Material. Queensland: Escape Reef: AMS I.22580-025, (17), 37 m; Raine Id: AMS I.20757-067, (20), 0–20 m; AMS I.20775-056, (18), 0–20 m; Tijou Reef: AMS I.20779-142, (18), 0–25 m; Yonge Reef: AMS I.19472-089, (16), 7– 15 m. Western Australia: Cartier Reef: NTM S.12883-010, (13), 13– 14 m. Rowley Shoals: WAM P.28024-33, (18), 35– 40 m.

Other material. We give details of the collections because of the relative rarity of this species in collections. American Samoa: AMS I.21998-002, 2(14–15), 20 m. Caroline Ids: BPBM uncat., 3(17–18), 12 m; USNM 313299, (14), 0–36 m; USNM 298765, 3(12–17), 0–25 m; USNM 223193, 3(11–13), 0–17 m; USNM 223195, 3(11–14), 0–17 m; USNM 298765, 3(12–17), 0– 24 m. Fiji: ROM 46001, 2(9–10), 23–30 m; ROM 46002, 2(7–18), 10–15 m; USNM 236756, (18), 30– 36 m. Indonesia: ROM 85385, 1(18), 45 m; USNM 210240, 3(16–16), 0–6 m; USNM 244186, 8(16–18), 9– 15 m. Marshall Ids: BPBM 12181, (18), 46 m. Palau: BPBM 31421, 4(16–17), 13–16 m; ROM 74801, 3(14–15), 14–26 m; ROM 74802, 4(7–16), 15–27 m; ROM 74926, 3(14–17), 12–21 m; ROM 80391, (14), 20–27 m; ROM 80410, (18), 18–34 m; ROM 80489, (16), 8– 14 m. Papua New Guinea: USNM 244098, (18), 34 m. Philippines: ROM 52976, 2(17–18), 5–12 m; ROM 52977, (17), 9–21 m; ROM 52978, (15), 15–21 m; USNM 243918, 28(11–18), 0–25 m; USNM 243919, 8(16–21), 0–25 m; USNM 264524, (19), 0–25 m; USNM 295300, (14), 6– 12 m.

Diagnosis. A species of Trimma with a broad interorbital, with a shallow pit above the middle of the eye, followed by a very short median fleshy ridge (often collapsed) posteriorly between two large papillae, no groove behind the eye; predorsal completely scaled forward to above the middle of eye, anterior-most scale enlarged, posterior scales ctenoid, anterior 2–3 rows of predorsal scales cycloid; cheek with a single row of cycloid scales; operculum with 5–7 cycloid scales; pectoral-fin base covered with 5 or 6 cycloid scales, uppermost 1–2 scales largest (distinctly enlarged); prepelvic area covered with 5 or 6 rows of cycloid scale, segmented caudal rays usually 15, rarely 16; pectoral rays unbranched; pelvic fins largely separate, connected only at the base, pelvic fins widely separate, distance between the bases of the fins about half to three-quarters of the base of each pelvic fin; fifth pelvic ray usually unbranched, others with a single branch (2 terminal tips); 40–60% the length of the fourth; second and third dorsal spines subequal in length, none filamentous; dorsal and anal rays usually I 8; body from second dorsal fin origin posteriorly darker than the front, becoming progressively darker posteriorly; a black stripe along the bases of each dorsal fin; pelvic spine usually with a dark brown margin; caudal fin clear to white.

Description. The description is primarily based on specimens from the Great Barrier Reef, Samoa and Indonesia. Dorsal fin usually VI + I 8 (I 7 in 22% of individuals), second to fourth rays longest and subequal in length, reaching to interspace between two dorsal fins when adpressed, first ray of dorsal fin usually branched, anterior element of last element branched; anal fin I 8 (rarely I 9, in 6% of individuals), first ray unbranched, anterior element of last ray branched; pectoral fin 12–15 (see Variation, discussion below), reaching just posteriorly to a vertical in line from just beyond anal spine to about second segmented ray, rays unbranched; pelvic fin I 5, fins widely separate with very low connecting membrane, distance between bases of fins; subequal to base of each pelvic fin; first four rays with one sequential branch, fifth ray with one dichotomous branch (two terminal tips) or rarely unbranched, 40%–65% length of fourth ray, which reaches posteriorly to below anal spine to about second segmented ray. Lateral scales 22–26; transverse scales 6–9; scales on preopercle, opercle and pectoral-fin base cycloid, breast scales cycloid on midline, ctenoid or cycloid to sides, but scale between bases of pelvic fins cycloid, and sometimes anteriormost 1–2 scales on midline of belly cycloid, remaining scales ctenoid; scales extending to above middle of eye; scales below dorsal fin with small accessory scales; pectoral-fin base with two vertical rows of cycloid scales, central scale vertically elongate in anterior row and dorsal-most scale vertically elongate in second row; prepelvic area with 5–7 rows of cycloid and ctenoid scales. Teeth in lower jaw consist of an enlarged outer row of curved, slightly enlarged canines and an inner row of similar, but smaller canines with irregular rows of small conical teeth in between; outer row of teeth in upper jaw similar to those of lower jaw, with small irregular inner rows of teeth. Tongue tip rounded. Gill opening extending anteroventrally to below posterior margin of pupil; outer gill rakers on first arch 3 + 12–14 = 15–17 ( Hagiwara & Winterbottom, 2007 reported 3–4 + 11–13 = 15–17).

Anterior nares a narrow tube, posterior nares a large pore with a raised rim; nasal sac slightly elevated as a raised oval sac located just above upper lip, openings separated by about 1–2 nares diameters. Interorbital as described in diagnosis. Vertebral pattern is Type B.

Colour pattern. Freshly collected. From slides of freshly collected specimen from Raine Island ( Fig. 14 A), Yonge Reef and Escape Reef, Queensland. Head and anterior half of body largely yellow with scattered grey spots due to dense concentrations of melanophores; cheek yellowish-grey; posterior half of body (from below posterior end of first dorsal fin) grading anteriorly from yellowish grey to black on caudal peduncle; first dorsal fin yellowish to largely grey, with yellowish tinge; second dorsal and anal fins with thin basal black stripe, followed distally by broad yellowish-orange stripe and then a thin submarginal black line; distal margin of fins white; caudal fin white; pelvic fins yellowish-grey, with white outer margin; pectoral fin a translucent orange. See under ‘Variation’ for differences in colour pattern from other localities, and live colour.

Preserved. Head, body and fins brown, except for caudal fin; caudal peduncle grey to black; caudal fin white to clear.

Variation. Insufficient material was available for any statistical analysis of the geographical variation of meristic features. Also, many specimens were in poor conditions and obtaining accurate counts was not always possible. However pectoral ray counts may vary geographically. Hagiwara and Winterbottom (2007) reported 13–15 pectoral rays with an average of 14 rays. Many of the specimens studied for this paper were in poor condition with a damaged pectoral fin. However, most from Indonesia and Australia appeared to have 12 or 13 pectoral rays.

Specimens from Australia and Samoa show considerable differences from material described from Japan by Hagiwara and Winterbottom (2007). In particular the black pigment on the caudal peduncle extends forward to under the second dorsal fin and the dark colouration decreases forward, but there are dense concentrations of melanophores up to the head. Specimens from Japan and the Philippines generally have the black bar confined to the caudal peduncle. In addition, fresh specimens from Australia and Samoa typically have a black submarginal band on the second dorsal and anal fin, followed by white at the tips of the fins. Hagiwara and Winterbottom (2007) reported a similar colouration in a specimen from Ambon, Indonesia. Specimens from Japan and the Philippines generally have a broad light area distally on the second dorsal and anal fins.

A photo of a freshly collected specimen from Samoa shows a similar colouration to Australian specimens, except that the anterior body is darker, with only a trace of yellowish-orange pigment. Colouration of fresh material from the Philippines and Palau ( Fig. 14 B) was described by Hagiwara and Winterbottom (2007). The colouration in these specimens and one from the Marshall Islands is generally lighter than Australian and Samoan specimens and there is often yellow on the caudal fin. A live specimen from Raja Ampat (Pl. 1 G) has a mostly yellow body and head, with a dark red-brown posterior part of the caudal peduncle, more intense and extending further anteriorly along the ventral surface. There is a dark basal band in the dorsal and anal fins, followed by a slightly wider yellow stripe; the distal half to one-third of the fins is hyaline; and the pelvic fin is yellow grading to light pink distally.

Hagiwara and Winterbottom (2007) reported completely separate pelvic fins, but material studied here (including the holotype) shows a low membrane connecting the bases of the two fins. The holotype and the specimen from Palau figured by Hagiwara and Winterbottom (2007) have a snout pointed in lateral view, with a convex dorsal margin and very narrow suborbital. All specimens examined in this study have the snout with a notch or concave dorsal margin and a broader suborbital. It is not clear if these differences are due to different methods of preservation, abnormalities or indicative of separate species.

The interorbital fleshy ridge is often collapsed. The type material largely lacks the ridge, but it is discernible in some of that material, although only extending forward to between the interorbital papillae above the middle of the eye. In Australian material the ridge normally extends well forward of these interorbital papillae. However, because it is collapsed in most specimens there is not adequate material to determine if the differences are consistent.

Given the colour and head shape variation and possible pectoral-fin count variation, it is likely that more than one species is involved.

Etymology. From the Latin ‘flavus’, meaning yellow, and ‘atrum’, black, in allusion to the unusual yellow and black colouration of the new species.

Distribution. Trimma flavatrum is known from outer edge of the Great Barrier Reef from Tijou Reef to Escape and from Cartier Reef in the Timor Sea off Western Australia. The species is not known from mid- or in-shore reefs on the Great Barrier Reef. In Australia the species is known from depths of 7–37 m, and to depths of 46 m outside of Australia, where it occurs eastward to Samoa, and north through Palau and the Caroline Islands to the Ryukyu Islands ( Fig. 15 ).

Comparisons. Hagiwara and Winterbottom (2007) compared Trimma flavatrum with T. tevegae stating that T. tevegae possessed a median fleshy ridge in the interorbital ridge, which is lacking in T. flavatrum . However, elsewhere in the paper they record a median fleshy ridge in the interorbital in Trimma flavatrum . Both species have the ridge, but it is better developed in T. tevegae as a rod-shaped ridge reaching to between the papillae near the anterodorsal margin of the eye, while the ridge is triangular in T. flavatrum , only reaching to between the papillae above the middle of the eye with a pit anterior to the ridge. Trimma tevegae lacks the pit in the interorbital region. The combination of the colouration, interorbital and 15 segmented caudal rays readily separates this species from all others. Only two specimens, both from Palau, were available for genetic analysis ( Winterbottom et al., 2014).

Discussion. This species has been referred to informally as Trimma DFH sp. 14 and Trimma RW sp. 25. The holotype is the largest specimen known at 23 mm SL.

Figures

FIGURE 14. Trimma flavatrum. A: 18 mm SL, AMS I. 20775 - 056, Raine Id., Queensland. B: 15.5 mm SL female, ROM 83348, Helen Reef, Palau. Photos by D. F. Hoese (A) and R. Winterbottom (B).

FIGURE 15. Map of the distributions of Trimma flavatrum (solid inverted triangles) and T. hoesei (solid pentagons). A solid square with a white center indicates localities at which both species occur.