Trimma stobbsi Winterbottom, 2001, Winterbottom, 2001

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: 78-81

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Trimma stobbsi Winterbottom, 2001


Trimma stobbsi Winterbottom, 2001  

Stobbs’ Pygmygoby

Figs. 44–45 View FIGURE 44 View FIGURE 45 , Pl. 3 F

Trimma stobbsi Winterbottom, 2001: 20   ( New Caledonia, also Maldives, Indonesia, the Philippines, Papua New Guinea, Solomon Ids, New Caledonia, and western Australia); Hayashi & Shiratori, 2003: 42; Anderson, 2005: 105; Allen et al., 2004: 331; Allen & Erdmann, 2012: 947 (western Pacific).

Australian material. Western Australia: Ashmore Reef: WAM P. 31437 -033, (13), 1– 7 m.

Other material. The following lists material we examined from localities that had not previously been reported for this species: Indonesia: Flores: AMS I. 34500 -027, 14 (12–17), 29– 30m. Raja Ampat: ROM 84882 View Materials , 3(16–17), 70 m; ROM 84889 View Materials , 11(13–17), 56 m; ROM 84900 View Materials , 18(10–16), 8–25 m; ROM 85086 View Materials , 2(10–15), 50 m; ROM 85135 View Materials , 14(8–14), 20–23 m; ROM 85146 View Materials , 3(10–16), 42 m; ROM 85157 View Materials , (13), 20–23 m; ROM 85188 View Materials , (17), 52 m; ROM 85203 View Materials , 3(9–14), 18–23 m; ROM 85229 View Materials , (15), 12–16 m; ROM 85244 View Materials , (12), 12–26 m; ROM 85276 View Materials , 5(8–15), 15–22 m; ROM 85291 View Materials , 3(9–17), 2–28 m; ROM 85316 View Materials , 4(12–15); ROM 85329 View Materials , 10(8–17), 18–21 m; ROM 85332 View Materials , 13(10–17), 66 m; ROM 85345 View Materials , 11(10–17), 20–27 m; ROM 85359 View Materials , 9(10–17), 60 m; ROM 85368 View Materials , 5(11–17), 55 m; ROM 85373 View Materials , 5(12–17), 14–18 m; ROM 85392 View Materials , 22(12–17), 45 m; ROM 87422 View Materials , 4(9–17), 6–21m; ROM 87455 View Materials , 5(10–16), 15– 18 m. Palau: Main Ids: ROM 74938 View Materials , (16), 12–21 m; ROM 74786 View Materials , (15), 14–26 m; ROM 74787 View Materials , 3(17–19), 15–27 m; ROM 76416 View Materials , 2(8–13), 18– 30 m. South West Ids: ROM 82982 View Materials , 4(15–175), 20–36 m; ROM 82994 View Materials , 10(9–20), 16–33 m; ROM 83018 View Materials , 7(16–19), 20–31 m; ROM 83028 View Materials , 4(18–19), 7–15 m; ROM 83041 View Materials , 6(15–18), 20–35 m; ROM 83045 View Materials , 6(15–19), 12–30 m; ROM 83060 View Materials , 2(15–21), 18–30 m; ROM 83069 View Materials , 10(16–19), 16–28 m; ROM 83148 View Materials , (17), 8–20 m; ROM 83257 View Materials , 3(8–16), 20–35 m; ROM 83270 View Materials , 2(17–18), 22–34 m; ROM 83295 View Materials , 3(13–15), 24–32 m; ROM 83395 View Materials , 3(16.1 –17.0), 22– 35 m. Papua New Guinea: Rabaul: ROM 88137 View Materials , 6(12–15), 16 m; ROM 8157, 4(12–16), 19 m; ROM 92132 View Materials , 5(10–17), 26 m; ROM 92245 View Materials , 7(12–15), 20 m; ROM 92284 View Materials , 10(8–16), 18 m. Vietnam: ROM 73196 View Materials , (18), 23– 29 m.

Diagnosis. A species of Trimma   with a yellow head, a grey-brown body, and a distinct oval dark spot above and just anterior to the posterodorsal corner of the operculum. This spot is preceded by a shallow groove which extends along the dorsal margin of the operculum. No predorsal scales, posterior half of the nape with a slightly developed longitudinal ridge in the midline, scales present on either side of the ridge with a very narrow scaleless gap between them; slight interorbital trench which extends posteriorly barely beyond mid pupil, no postorbital trench; fifth pelvic-fin ray unbranched and 50–70 % of the length of the fourth.

Description. The following is based on the original description because only a single specimen is currently known from Australian waters. Dorsal fins VI + I 9–10, (mean = 9.1, n = 47), second spine not elongated or occasionally slightly elongated, reaching posteriorly to base of spine or first ray of second dorsal fin when adpressed, first ray of second dorsal fin branched or unbranched, all remaining rays except posterior half of last ray branched; A I 8–9 (mean = 9.0, n = 47, 8 twice); P 16–19, (mean = 17.6, n = 47, 16 twice, 19 twice), variable number of uppermost and lowermost rays unbranched with branched rays in between, may all be unbranched in smaller specimens <13 mm SL, reaching posteriorly to vertical through base of first anal fin ray or just anterior to this; V I 5, no fraenum, basal membrane vestigial, first four rays with a single sequential branch, fifth ray unbranched (one dichotomous branch on one side in three specimens), 50–70 % of length of fourth ray, fourth ray reaching posteriorly to first to fifth elements of anal fin. Lateral scales 22–24 (mean = 23.4, n = 38), transverse scales 7–8 (mean = 7.4, n = 43); no predorsal scales in midline; a slightly developed, raised, longitudinal fleshy ridge from anterior of dorsal fin to mid-nape, scales on either side of ridge with a narrow scaleless gap between them, gap widens towards head where ridge ends; two specimens with one and two scales respectively across nape anterior to ridge; no scales on cheek or opercle; scales on breast (usually five rows), belly, and pectoral-fin base (4 vertical rows) cycloid; scales extend anteriorly 1 / 2 to one scale width posterior to eye. Ventral attachment of gill opening anywhere between vertical through posterior margin and mid-point of pupil. Teeth in both jaws of outer row of curved, evenly spaced, enlarged canines, with inner row of smaller conical teeth. In some specimens large outer canines on lower jaw appear to be in pairs, with gap between each pair. Tongue truncate or rounded. Gill rakers on first arch 2–4 (2 twice) + 11–15 (11, 15 once each; mean = 3.5 + 12.9, n = 34). Anterior nares long narrow tube, posterior nares pore with raised rim. Bony interorbital quarter to half pupil width, with poorly developed interorbital trench which does not extend posteriorly beyond posterior third of pupil; no postorbital trench. Abdominal/caudal vertebral transition Type B.

Colour pattern. Freshly collected. From 35mm colour slides of living specimens from Ataoru, Flores, Raja Ampat (Pl. 3 F) and Sabah. Distinct round to oval spot (vivid red to dark red-brown) above and just anterior to posterodorsal corner of opercle. Head yellow, with brown chromatophores, yellow pigment extending around eyes and along sides of head just beyond opercular spot. Tinges of pink on opercle (probably from gill filaments) and pectoral base. Body ranging from light yellowish-brown to dull grey brown, with colour extending anteriorly to behind pectoral-fin base and along nape just posterior to eye. Scale pockets faintly outlined with brown chromatophores. Dorsal fins with brown chromatophores, a yellow stripe just above base. Specimen from Flores with yellow head and body appears to be bright salmon pink, although brown chromatophores present. Iridocytes present on pectoral fins of Flores specimen only.

Freshly dead. From 35mm colour slides of specimens from Vietnam ( Fig. 44 View FIGURE 44 ), the Philippines, Palau, Indonesia, and New Caledonia. Background colour of head and body uniform orange or yellow, with numerous brown chromatophores throughout. Distinct black spot (third pupil size) above and anterior to posterodorsal corner of opercle, preceded by groove which runs along two-thirds of dorsal margin of opercle. Greatest concentration of brown chromatophores on body just above pectoral fin and posterior to opercular spot. Scale pockets outlined with orange or yellow and brown chromatophores. Base of dorsal and anal fins with brown chromatophores, single row of orange or yellow spots on fin rays of both dorsal fins, similar spots on base of caudal fin; opercle, pectoral-fin base, and pectoral fin pinkish.

Preserved. Background colour of head and body pale straw yellow sprinkled heavily with brown chromatophores, body appears straw yellow to light brown, head and belly (with fewer chromatophores) straw yellow. Dorsal and anal fins dusky, with row of light spots just above bases of dorsal fin rays; pectoral fins hyaline.

Caudal and pelvic fins sprinkled lightly with chromatophores; scale pockets clearly outlined on anterior half of body.

Etymology. Named for Robin E. Stobbs, friend, guru, and colleague of RW, whose expertise in so many things was instrumental in launching RW’s career (especially the field-work aspects) many years ago at the JLB Smith Institute of Ichthyology in Grahamstown, South Africa.

Distribution. The species has been found in the Indian Ocean at the Maldive Islands. In the Pacific it has been recorded from Western Australia (a single specimen from Ashmore Reef), Indonesia, the Philippines, Vietnam, Papua New Guinea, Solomon Islands, Vanuatu, and New Caledonia ( Fig. 43 View FIGURE 43 ). The specimens have been collected in 1–40 m of water, on reefs and drop-offs, and in caves.

Comparisons. Trimma stobbsi   shares the characteristics of a distinct opercular spot and no scales in the predorsal with T. agrena   , T. fangi   , T. sheppardi   , and T. winterbottomi   , but the less complex colour pattern of T. stobbsi   easily distinguishes it from these four species in both the live and the preserved state. Trimma fangi   and T. agrena   differ from T. stobbsi   in possessing a pattern of yellow, orange or red spots and blotches on the head (which remain as light areas in preserved material), usually a full basal membrane, and a fifth pelvic-fin ray which branches dichotomously at least twice. Trimma winterbottomi   can be distinguished from T. stobbsi   by the dark banding pattern on the upper part of the body, well developed interorbital and postorbital trenches, full basal membrane and a fifth pelvic fin ray which is sub-equal to the fourth and branched dichotomously twice. Trimma sheppardi   and T. stobbsi   both have a raised longitudinal ridge that runs anterior from the dorsal fin to the mid-nape and the dark spot above the opercle. The spot on T. sheppardi   is an elongate oval (or two rounder spots side by side) and tends to be more posterior on the body so that much of the spot is above the pectoral-fin base, rather than just above the opercle as in T. stobbsi   . Trimma sheppardi   also has vertical bars on the head, dark internal blotches along the vertebral column, and no interorbital trench.

A barcode analysis of 11 specimens identified morphologically as T. stobbsi   was divided into three haplogroups ( Winterbottom et al., 2014). The first, from Palau and Raja Ampat (Group 1; n = 2) differed from the other two groups by a minimum of 12 %; the second group ( Palau only, Group 2; n = 3) differed from the third group from New Caledonia, Rabaul and Raja Ampat (Group 3; n = 6) by 8 % sequence divergence. The third group probably represents the same haplogroup as the holotype, which was collected at New Caledonia. These results suggest that there may be at least two other undescribed species currently identified as T. stobbsi   . No tissue samples are currently available from Australia, and we use the name here with some reservations.

This species has been informally referred to as Trimma   DFH sp. 36 or RW sp. 23.


Western Australian Museum


Royal Ontario Museum














Trimma stobbsi Winterbottom, 2001

Winterbottom, Richard & Hoese, Douglass F. 2015

Trimma stobbsi

Allen 2012: 947
Anderson 2005: 105
Allen 2004: 331
Hayashi 2003: 42
Winterbottom 2001: 20