Trimma striatum ( Herre, 1945 )

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 : 81-84

Trimma striatum ( Herre, 1945)

Redlined Pygmygoby

Figs. 8 A, 10, 46, Pl 3 G

Coronogobius striatus Herre, 1945:81 ( Philippines) .

Trimma sp. 2: Kuiter, 1992:236 E ( Indonesia).

Trimma striata: Burgess et al., 1990:577 (locality not given); Anonymous, 1995:99 (Surin & Similan Ids, Andaman Sea); Myers, 1999:pl. 163 ( Palau); Kimura & Matsuura, 2003:192 ( Indonesia); Allen et al., 2004:329 (western Pacific); Kuiter & Tonozuka, 2004:703 (x 2); Indonesia; Randall, 2005:553 (in part, figure from Palau); Kuiter & Debelius, 2006:662 ( Indonesia); Hayashi & Shiratori, 2003:42 ( Japan); Satapoomin, 2007:162 (Andaman Sea); Hoese & Larson, 2006:1690 (in part. Timor Sea); Allen & Erdmann, 2012:947 ( Maldives to Fiji).

Trimma striatum: Kuiter, 1996:361 (figure only); Kuiter, 1998:208 ( Maldives); Randall & Goren, 1993:22 ( Maldives — note: Pl. 4E is of a specimen from New Guinea).

Material. Holotype: CAS-SU 39854, 1(22), Coron, Busuanga Id, Philippines.

Australian material. Western Australia: Ashmore Reef: AMS I.2674 -019, 2(19–23), 15–16 m; AMS I.26745-010, 2(20–20), 2–10 m; AMS I.26749-015, 6(22–25), 4–5 m; NTM S.11965-068, 59(10–25), 10–12 m; NTM S.11966-012, 4(13–16); NTM S.11968-025, 5(12–20), 15–17 m; NTM S.11970-010, 5(12–24), 12–15 m; NTM S.11981-015, 7(12–22), 7–9 m; NTM S.11984-023, 9(12–22); NTM S.12322-022, 3(18–20), 12–13 m; WAM P.31434-025, 5(18–26), 3–6 m; WAM P.31436-047, 18(14–24), 3–6 m; WAM P.31437-026, 5(19–23), 3–6 m; WAM P.31438-051, 11(17–24), 4–6 m; Hibernia Reef: NTM S.13420-048, 24(9–23), 6–8 m; NTM S.13431- 0 17, (11), 5–9 m; WAM P.31196-001, 15(15–23), 22–23 m; WAM P.31378-010, 4(15–20), 24– 25 m.

Other material. Indonesia: Banggai Ids: WAM P.31503-001, 13(15–23), 15– 18 m. Flores: AMS I.34501- 0 65, 2(18–19), 12 m; AMS I.34502-034, 4(18–23), 4 m; AMS I.34503-049, 6(12–20), 6 m; AMS I.34504-030, 2(11–19), 17 m; WAM P.30719-022, 2(19–23), 13–20 m; WAM P.30719-022, 2(19–23), 6– 16 m. Papua: Teluk Sebakor: WAM P.32811-002, 3(19–20), 8– 15 m. Raja Ampat Ids: ROM 85089, 18(9–21), 18–23 m; ROM 85112, 10(13–17), 3–7 m; ROM 85121, 5(13–16), 15–31 m; ROM 85159, 34(9–22), 20–23 m; WAM P.31541-002, 4(14–21), 10–15 m; WAM P.31791, (17), 15–18 m; WAM P.32243-023, (21), 0.1–1 m; WAM P.32252-026, 3(13–15), 10–15 m; WAM P.33024-001, 12(17–20), 8– 12 m. Sulawesi: BPBM 26732, 2(17–18); NSMT-P.61020, 3(10–21), 20 m; NSMT-P.61466, 26(8–24). Sumatra: WAM P.31525-010, 4(14–21), 15– 40 m. Malaysia: Sabah: WAM P.30410-024, 8(16–23), 15– 20 m. Palau: AMS I.17938-001, (21), 6 m; AMS I.17938-001, (21), 6 m; ROM 80493, 75(9–22), 8–14 m; ROM 83079, 2(19–20), 2– 8 m. Philippines: BMNH 1983.3.25:937–939, 3(16–20). Bolinao: AMS I.21903-014, 23(13–19), 3–15 m; AMS I.23029-002, 2(18–19), 4 m. Calamian Ids: WAM P.31398- 0 21, (18), 10– 20 m. Busuanga: CAS-SU 39854, 1(22). Mindoro: AMS I.40159-028, (31.5). Palawan: LACM 42488–34, (20). Papua New Guinea: Madang: WAM P.30369-009, (21), 22–25 m; WAM P.30375-004, 2(20–21), 20–22 m; WAM P.30623-011, 3(9–21), 22–25 m; WAM P.31213-023, 3(19–20), 18–23 m; WAM P.31214-012, (20), 15– 18 m.

Diagnosis. A species of Trimma with a deep trench in bony interorbital about half-pupil diameter in width; a shallow trench behind the eye along the upper half of the posterodorsal margin of the eye; predorsal midline naked, sides of nape scaled to just behind the eye; cheek and operculum naked; basal membrane of the pelvic fins connected to the tips of the fifth ray, forming an indented plate; central 5–9 pectoral rays branched; head with 5–6 light stripes (orange to red in life) and blue interspaces; body uniformly coloured with a dense concentration of melanophores; snout light, with distinct dark stripes crossing the lips, (a median stripe, followed by a short stripe from the eye over the lips, the stripe continuing from under the eye crossing the lips posteriorly, lips largely pale, (except for the dark stripes); light stripe on the chin below the eye continuing onto the lower surface of the head anteriorly, continuous across the chin to the opposite side and not interrupted in the midline by a black median stripe (see Fig. 8 A); branchiostegal membranes largely dark, with a thin light stripe near the middle of membrane on each side.

Description. The description is primarily based primarily on specimens from Ashmore Reef in the Timor Sea. Dorsal fin VI + I 9 (rarely I 8 or I 10 in 8.1% of individuals), mean = 9.0, n = 37, second spine longest, reaching between posterior base of second segmented dorsal-fin ray to about last segmented ray when adpressed, sometimes third ray elongated into short filament; first segmented ray of dorsal fin usually unbranched in adults, anterior element of last element usually branched; anal fin I 8 (rarely I 7 or I 9, in 8.1% of individuals), mean = I 8.0, n = 37, first ray usually unbranched, anterior element of last ray branched; pectoral-fin rays usually 17 (in 65.8% of individuals) or 16 or 18 (in 31.6% of individuals), 19 (in 2.6% of individuals), mean = 17.1, n = 38; pectoral fin reaching just posterior to vertical in line between anal spine and third segmented anal ray; branching of pectoral rays variable, upper 4-8 pectoral rays unbranched, central 5–9 rays branched and lower 3–6 rays unbranched; V I 5, fifth ray about 80–90% length of fourth ray, ray thin and branched dichotomously (with 4–6 terminal tips); other four rays thicker and branched sequentially, fourth ray with 2–3 terminal tips, third usually with 2–3 terminal tips, and first and second rays with 2 terminal tips; pelvic fin reaching posteriorly to just anterior to anus in juveniles (<15 mm SL) to about third segmented ray of anal fin in adults; pelvic fraenum absent, basal membrane present, usually connected to tip of fifth ray, but often torn, forming indented plate; segmented caudal rays 16 (in 2), 17 (in 24); branched caudal rays 5/4 (1), 6/5 (25), 6/6 (2). Lateral scales, 24(18), 25(3), mean = 24.1; transverse scales usually 7 (13) or 8 (6), mean = 7.3; scales on pectoral-fin base, breast, anterior 1–2 rows on sides of nape and anteriormost 3–5 scales on midline of belly cycloid, remaining scales ctenoid; pectoral-fin base with 5–8 oval cycloid scales, arranged irregularly in about 2 rows horizontally and 4 rows vertically (missing in most specimen due to easy loss of scales); prepelvic area with 6–7 rows of cycloid scales, not extending forward onto isthmus anterior to posterior preopercular margin or onto sides of isthmus, single small embedded median scale between bases of pelvic fins, covering part of basal membrane; cheek and operculum naked; sides of nape scaled anteriorly almost to eye (less than one scale diameter from eye), scales extending anteriorly in line from side of first dorsal origin downward to near posterodorsal margin of eye; scales below second dorsal fin smaller than other scales on side. Head moderately compressed, eyes dorsolateral; nape crest low from first dorsal origin to above posterior quarter of operculum. Teeth in lower jaw with an enlarged outer row of curved canines spaced about twice width of each tooth anteriorly on dentary, followed by 3–4 inner rows of smaller canines tapering to two rows posteriorly, innermost row of slightly enlarged teeth (shorter than teeth in outer row, but longer than teeth in mid-rows); outer row of teeth in the upper jaw enlarged, curved and very wide-set, covering anterior half of premaxilla, with three to four small irregular inner rows of teeth anteriorly, tapering laterally to one row, anteriormost teeth in inner row slightly enlarged and directed posteriorly. Tongue tip triangular to truncate, with central point or slightly indented at anterior tip. Gill opening to below point between mideye and posterior end of pupil; gill rakers on first arch 4–5 + 14–16 = 19–21 (rarely 17 or 21, mean = 19.9 based on 7 specimens from Ashmore Reef, Indonesia and the Philippines); anterior nares at end of slender elongate tube just above upper lip; posterior nares with raised rim, one naris diameter from anterior and 2–3 diameters from eye; nasal sac elevated. Interorbital trough shallow, reaching just behind interorbital papillae above middle of eye, very short, shallow trench along posterodorsal margin of eye, bony interorbital narrow, width about one third or slightly less than pupil diameter; jaws forming an angle of 60–75° with body axis; horizontal line from tip of upper jaw passes through or just above lower margin of pupil; nape crest low from first dorsal origin to above posterior quarter of operculum. Posterior abdominal/anterior caudal vertebral pattern is Type B.

Colour pattern. Live and freshly collected, based on photos of freshly collected material from Philippines, Palau ( Fig. 46 ), New Guinea and Thailand and underwater photos provided by K. Hagiwara from Palau and M. Erdmann from Raja Ampat (Pl. 3 G).

Head with narrow reddish stripes, sometimes with tinge of orange; depth of stripes about half to one-third of charcoal blue interspaces; dark interspace forming stripe on midline from first dorsal origin forward to posterior interorbital space and continuing diffusely between eyes but distinct on snout; five light stripes on top and side of head: uppermost light stripe extending from dorsal margin of eye to below first dorsal origin in freshly collected material, but continuing faintly below first dorsal fin in life; second light stripe extending from posterodorsal margin of eye to below first dorsal fin in freshly collected material and continuing faintly to below second dorsal fin in life; third stripe from just above middle of eye, arching along dorsal margin of preoperculum and operculum, ending just above pectoral-fin base in freshly collected material to below first dorsal fin in life; fourth stripe beginning along middle of upper lip arching upward and continuing along lower iris extending posteriorly on to upper pectoral-fin base; fifth stripe beginning at posterior tip of jaw extending horizontally along cheek onto pectoral-fin base, just below middle; sixth stripe from below eye on lower surface of head extending to pelvic-fin origin posteriorly, usually broken into two sections by dark pigment on branchiostegal membranes (possibly extending forward of eye, but not fully visible from slides); top of snout largely red; body varying from overall charcoal grey colouration with faint reddish tinge to reddish-grey. Pectoral and pelvic fins largely translucent, often with orange tinge, base of pelvic fin reddish from sixth head stripe extending onto base of fin. First dorsal fin with series of orange to red spots, one centered on each dorsal spine forming broken stripe near base (much narrower than head stripes), rest of fin grey to dusky, sometimes darker ventrally. Second dorsal fin with 4 longitudinal rows of orange to red spots (centered on fin rays), similar to spots on first dorsal fin, sometimes lowermost series of spots forming stripe, but becoming irregular posteriorly; remainder of fin dusky to grey, rarely darker below lowermost series of spots. Anal fin grey to reddish, with reddish-orange pigment concentrated along fin rays; sometimes with thin reddish orange stripe near base of fin. Caudal fin with orange to red pigment concentrated along fin rays, sometimes forming faint oval spots, with membranes grey.

Preserved. Pattern of colouration generally similar to fresh colouration, with red and orange becoming light brown. A sixth light stripe extending from chin to pelvic-fin origin, not visible from slides, but probably reddishorange as in other stripes in life, usually broken into two sections by dark pigment on branchiostegal membranes, or narrowing on branchiostegal membranes. Reddish-orange stripes becoming light brown and interspaces dark grey to black. Median dark stripe from dorsal origin sometimes faintly discernible between eyes, but distinct on snout. Upper stripe from anterior margin of eye present at all sizes; middle and lower stripes only narrowly cross upper lip, but not lower lip. Lower lip uniformly light, with 3–5 small concentrations of melanophores. Lower surface of head usually with light dark stripe extending from lower operculum (fifth stripe), crossing lower lip and curving to meet stripe from other side just behind chin and without dark stripe connecting these bars with lower lip, but often with dark area on dark interspace on median of chin ( Fig. 8 A); sixth stripe also crossing midline without pigment in interspace; narrow dark interspace crossing midline just behind lower lip; branchiostegal membranes largely dark, but often faded on older preserved specimens. Body light brown, with dense concentration of melanophores on each scale, becoming sparse posteriorly; no light coloured areas on centers of scales, Dorsal, anal and caudal fins with scattered melanophores forming faint spots. Pectoral fin translucent. Pelvic fins largely translucent, sometimes with melanophores along membranes between some rays at base.

Etymology. From the Latin ‘striatus’ (striped), presumably in reference to the stripes on the head.

Distribution. Trimma striatum is known in Australia only from Ashmore Reef and Hibernia Reef in the Timor Sea. The species is found from Palau and Japan to Indonesia, Thailand, and the Maldives, and is syntopic with Trimma capostriatum in northern and eastern New Guinea and in the South West Islands of Palau ( Fig. 10 ). It is found over a wide range of depths from 1– 40 m.

Comparisons. The species is most similar in colouration and fin-ray and scale counts to Trimma capostriatum . See that species for comparisons.

Eleven specimens of T. capostriatum from the Great Barrier Reef and Rabaul, New Britain differ in their CO1 genome by 9% from six specimens of T. striatum from Palau and Raja Ampat, supporting the conclusion that there are two species ( Winterbottom et al., 2014). Based on the colour differences, the two species were taken together in the same collection at Helen Reef (SW Islands of Palau).

Discussion. Specimens from Palau and the Philippines are generally dark, with the dark pigment obscuring the reddish body colouration. Specimens from Thailand and New Guinea are generally lighter, with the reddish pigment being more intense than the dark pigment. Specimens from Palau have a distinct stripe on the proximal part of the anal fin; that fin is normally uniformly coloured in specimens from other areas.

Figures

FIGURE 8. Ventral view of the heads of A: Trimma striatum (20.0 mm SL male, ROM 83138) and B: T. capostriatum (19.2 mm SL male, ROM 84493), Helen Reef, Palau. See text for arrows. Photos by R. Winterbottom.

FIGURE 10. Distribution map for Trimma capostriatum (solid inverted triangles) and T. striatum (open inverted triangles).

FIGURE 46. Trimma striatum, 21.4 mm SL male, ROM 74959, Babeldaob Id., Palau. Photo by R. Winterbottom.