Trimma tigrinum Chen & Harefa, new species

(Figures 1‒2)

New english name: Tiger pygmygoby.

Materials examined

Holotype: NTOUP-2008-07-294, female, 1 specimen (20.1 mm SL), Jihue, Chenggong Township, Taitung County, Taiwan, depth 6–7 m, coll. coll. IS. Chen, 16 July 2008.

Paratypes

Taitung county NTOUP-2008-07-295, 2 specimens (18.7–18.9 mm SL), same data as holotype. NTOUP-2020-09-065, 4 specimens (19.5–24.2 mm SL), Jihue, Chenggong Township, depth 6–7 m, coll. T. Harefa, 29 September 2020.

NTOUP-2021-02-114, 1 specimen, female (22.4 mm SL), Jihue, Chenggong Township, depth 5–6 m, coll. T. Harefa & DY. Hong, 25 February 2021.

NTOUP-2021-09-220, Male, 1 specimen (27.1 mm SL), Jihue, Chenggong Township, Taitung County, Taiwan, depth 6–7 m, coll. T. Harefa & D.Y. Hong, 24 September 2021.

NTOUP-2021-09-221, 5 specimens (15.5–20.0 mm SL), Jihue, Chenggong Township, Taitung County, Taiwan, depth 6–7 m, coll. T. Harefa & D.Y. Hong, 24 September 2021.

NTOUP-2021-09-222, 6 specimens (21.8–24.6 mm SL), Jihue, Chenggong Township, Taitung County, Taiwan, depth 6–7 m, coll. T. Harefa & D.Y. Hong, 24 September 2021.

NTOUP-2021-12-182, 5 specimens (19.4–25.4mm SL), Jihue, Chenggong Townshi, depth 6–7 m, coll. T. Harefa & DY. Hong, 21 December 2021.

NTOUP-2023-01-102, 1 specimen (22.2 mm SL), Jihue, Chenggong Township, depth 5–6 m, coll. T. Harefa et al., 12 January 2023.

Pingtung county NTOUP-2020-11-093, 4 specimens (24.9–26.8 mm SL), Tiaoshi, Hengchun Township, depth 5–6 m, coll. T. Harefa, 16 November 2020.

NTOUP-2021-04-099, 3 specimens (21.4–23.8 mm SL), Nanren, Manzhou Township, depth 5–8 m, coll. T. Harefa & JZ. Ho, 02 April 2021.

NTOUP-2022-01-050, 4 specimens (23.0– 25.5mm SL), Tiaoshi, Hengchun Township, depth 4–5 m, coll. T. Harefa & DY. Hong, 22 January 2022.

NTOUP-2022-01-051, 1 specimen (24.9 mm SL), Hongchaikeng, Hengchun Township, depth 8–12 m, coll. T. Harefa et al., 23 January 2022.

NTOUP-2022-01-052, 4 specimens (23.2–25.6mm SL), Shanhai, Hengchun Township, depth 8–9 m, coll. T. Harefa et al., 22 January 2022.

New Taipei City NTOUP-2021-08-059, 1 specimen, female (22.1 mm SL), Maoao, Gongliao District, depth 8–12m, coll. T. Harefa & DY. Hong, 09 August 2021

Nontypes

NTOUP-2021-09-219, 5 specimens (14.8–17.8 mm SL), Jihue, Chenggong Township, depth 6–7 m, coll. T. Harefa, 29 September 2020.

NTOUP-2021-11-148, 12 specimens (17.8–21.4 mm SL), Jihue, Chenggong Townshi, depth 5 m, coll. T. Harefa & DY. Hong, 17 November 2021.

NTOUP-2021-12-189, 5 specimens (16.2–18.8 mm SL), Jihue, Chenggong Townshi, depth 6–7 m, coll. T. Harefa & DY. Hong, 21 December 2021.

NTOUP-2023-01-103, 2 specimens (17.3–19.8 mm SL), Jihue, Chenggong Township, depth 5–6 m, coll. T. Harefa et al., 12 January 2023.

Diagnosis

The new species Trimma tigrinum sp. nov. is well distinguished from other congeners by the following unique combination of features: (1) fin rays: D2 I/9, A I/9, P 17–19; second and third spines of D1 equal in length and not elongated; D2 rays branched; first ray of A not branched; fifth ray of V unbranched. (2) Squamation: LR 23–24 (modally 23), TR 6–7 (modally 7), PreD 7–8; no scales on the cheek and opercle. (3) Interorbital width narrow with deep trench and postorbital trench with slightly groove. (4) Specific colorations: cheek with two yellow vertical bands; anterior margin of pectoral-fin base with large yellow bar, two third of pupil diameter-sized; spine of second dorsal-fin with two small, dark reddish spots. dorsum from D1 to dorsal procurrent caudal-fin with seven yellow-orange bands like saddles; ventral from origin A to ventral procurrent caudal-fin with five diffuse yellowish or reddish orange bands.

Description

Body proportion in Table 1. Body moderately elongated, slightly compressed posteriorly. Head slightly depressed anteriorly. Mouth oblique, maxilla extending posteriorly to slightly beyond vertical drawn through anterior margin of orbit. Lower jaw protruding slightly beyond tip upper jaw. Anterior nasal with a short tapering tube reaching anteriorly to above anterior margin of upper lip, posterior opening pore-like with low raised rim. Eyes large, dorsolateral. Interorbital narrow, with deep trench and postorbital trench with slightly groove. Cheek slightly fleshy. Gill opening on each side large, extending anteroventrally to vertical drawn through posterior edge of mid-pupil.

Fins. —D1 VI, D2 I/9, A I/9, P 16–19 (modally 18), V I/5+I/5 (distribution frequency in Table 2). Second to fourth spine of D1 equal in length, not elongate, and not reaching origin D2, when adpressed. D2 rays all branched and last ray always two rays with one branched. A origin located below first ray of D2; first ray usually unbranched remaining rays branched and last ray always two rays with one branched. Upper 2-4 (usually 2–3) and lower 2–8 (usually 2–7) of P rays unbranched, central 6–14 (usually 8–11) rays branched. V no fraenum, basal membrane vestigial (about 3-12% length of fifth ray); first to fourth ray branched once; fifth ray unbranched, 40–50% length of fourth ray; fourth segmented ray longest reaching between first to third segmented ray of A.

Scales. —LR 23–25 (modally 24), TR 6–7 (modally 7), PreD 7–8 (modally 7) SDP 4; cheek and opercle region naked; three rows of cycloid scales on pectoral-fin base; cycloid scales on breast, pelvic-fin base and belly.

Head lateral-line system.—(Figure 2)

Canals: No canal pore on head.

Sensory papillae: Distributed as follows, with counts and ranges shown in parentheses: row a (6) long, extending from posterior to anterior of orbit; rows b and d (8–9 and 8–9 respectively); row c (6) present longitudinally below infraorbital; single cp pappilla (1); rows e and i (34–35 and 14–15, respectively) on preoperculo-mandibular; row f (3 paired papillae) on rostral mandibular; rows n and g (1 and 5 respectively) anteriodorsal; rows ot, oi and os (18–19, 5–6 and 6–7, respectively) on opercular; p papillae (6, paired) longitudinally on interorbital; rows r and s (2 and 1, respectively, all paired) flanking midline in preorbital area; rows u, x and z (4–5, 5–6 and 8–9, respectively) on oculoscapular.

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Colouration while fresh

Head and body with whitish-pale yellow or pink background. Scale pockets outlined with brown melanophores. Head with 4 yellowish vertical bars, scattered with brown melanophores: first bar extending vertically from anteroventral margin of eye to posterior end of maxilla; second bar extending from posteroventral margin of eye to posteroventral of cheek; third bar behind the eye, connecting to band on anterior nape and extending vertically along to middle preopercular, larger dorsally and grading to thin bar ventrally; fourth bar extending from upper posterior opercle to middle of opercle. Mid-anterior of pectoral-fin base with yellowish-orange blotch, two third of diameter-pupil size, and a small blotch, same colour, on upper posteriormost near rays. Snout yellow, lighter anteriorly and darker posterioly. Iris dark gold with thin yellow margin around pupil. Body with irregular yellow-darker blotches, somewhat larger dorsally, gradding to lighter ventrally. Dorsum from first dorsal fin to dorsal procurrent caudal fin with seven yellow-orange bands like saddles, scattered with brown melanophores. Ventral from origin of anal fin to ventral procurrent caudal fin with five diffuse yellowish or reddish-orange bands, lighter anteriorly to strong colored posteriorly. Both dorsal fins with two yellowish orange or reddish-orange stripes; upper stripe broader; outer margin whitish; first, fifth and sixth spine of first dorsal-fin with small dark reddish spot; spine of second dorsal fin with two small dark reddish spot. Anal fin with broad yellowish-orange or reddish-orange stripe, outer margin whitish. Pectoral and pelvic fins hyaline with yellowish or pinkish rays. Caudal fin with 4 yellowish or reddish-orange stripes, extending posteriorly; sometimes with some small dark reddish spot, dorsal and ventral margin whitish, posterior margin scattered with brown melanophores.

Colouration in preserved (based on holotype). Head and body creamy yellow, marking bars on cheek, nape, pectoral-fin base with brown melanophores. Brown blotches on dorsum strongly colored with brown melanophores anteriorly and fading posteriorly. Ventral body without blotches. Dorsal-fin translucent with black spots on spines; upper posterior margin of second-dorsal fin scattered with brown melanophores. Anal-fin translucent with brown melanophores scattered basally. Pectoral-fin and pelvic-fin translucent. Caudal-fin tranclucent with brown melanophores scattered on posterior margin of segmented rays.

Distribution

Currently known from the coastal regions of northern to southeastern Taiwan.

Etymology

The specific name, tigrinum derived from the latin “ tīgris” meaning tiger, in allusion to the bars and spots on head and body.