Trimma pajama, Winterbottom, Richard, Erdmann, Mark V. & Dita Cahyani, N. K., 2014

Winterbottom, Richard, Erdmann, Mark V. & Dita Cahyani, N. K., 2014, Three new species of Trimma (Pisces; Gobioidei) from Indonesia, Zootaxa 3838 (3), pp. 367-384 : 374-378

Trimma pajama n. sp.

( Figures 4–6 )

Suggested common name: Pajama pygmy goby.

Trimma species 2— Allen & Erdmann, 2012: 946 (Kalimantan, Moluccas in Indonesia, Papua New Guinea, Solomon Is., Palau, and Tonga).

Material Examined. Three lots, 11 specimens (11.8–15.6 mm SL) from Raja Ampat (Penemu Is.) and the Fakfak Peninsula, West Papua, Indonesia.

Holotype. ROM 94175, 14.0 mm SL female, Indonesia, SW side of Fakfak Peninsula near Ekka, (02° 58.050' S, 132° 06.846' E), 10 m, clove oil. 21 Jan., 2013, M. V. Erdmann.

Paratypes. AMS I.46370-001, 1 (14.3), collected with the holotype. MZB.22093, 3 (11.8–13.3), collected with the holotype. ROM 94928, 2 (12.5–13.3), collected with the holotype. ROM 94899, 2 (15.0–15.6), Indonesia, Raja Ampat, Fam Is., Penemu I., lagoon, (00° 35.534’ S, 130° 17.236’ E), Halimeda algae bed, 6 m, clove oil, 28 Nov., 2013, M. V. Erdmann. ROM 95784, 1 (12.5), Indonesia, Raja Ampat, Fam Is., Penemu I., lagoon, (00° 35.332.0’ S, 130° 14.2’ E), Halimeda algae bed, 3 m, clove oil, 19 Aug., 2013, M. V. Erdmann. ROM T12762, 1 (12.9), and ROM T 12763 1 (14.6), collected with the holotype; tissue specimens for genetic analysis. USNM 427489, 1 (13.5), collected with the holotype.

Non-type Material. ROM 80296, (1), Palau, between Garreru and Balbeldoab Is. USNM 209629, (4), Indonesia, Ceram, Tandjung Liang. USNM 264527, (1), Papua New Guinea, Hermit Is., Pechu I. MB0613101, (1), collected with ROM 94899, tissue specimen.

Diagnosis. Trimma pajama has 6 scales in the predorsal midline, two ctenoid scales along the upper border of the opercle, no cheek scales, first two dorsal spines slightly elongated and reaching posteriorly to between the base of the spine and the base of the first ray of the second dorsal fin, rays of the pectoral fin unbranched, a fifth pelvic fin ray which branches once dichotomously and is 58–72% the length of the fourth ray, and a full basal membrane connecting the inner margins of the fifth pelvic fins rays in undamaged specimens. The live colour pattern of redorange and dark brown or grey stripes on the body reaching posteriorly to the anterior half of the caudal peduncle is unique among members of the genus, as is the preserved colour pattern of dark and light body stripes.

Description. Dorsal fins VI + I 8, first and second spines slightly elongate, reaching posteriorly to between bases of spine and ray 1 of second dorsal fin when adpressed, rays branched except, usually, posterior element of last ray and, in 2 of 11 specimens, the first ray, last ray reaching posteriorly 39 –52% of distance from its base to first dorsal procurrent ray; anal fin I 8, all but posterior element of posteriormost ray and first ray branched (first ray unbranched in two specimens); posteriormost ray 24 –40% of distance from its base to first ventral procurrent ray; pectoral fin 12– 13 –14 (mean 12.7), all rays unbranched, fin reaching posteriorly to a vertical line between just anterior to anal spine and base of first ray of anal fin; pelvic fin I 5, no frenum, basal membrane 100 % length of inner branch of fifth ray when undamaged, first four rays with one sequential branch, fifth ray branched once dichotomously and 58– 70 –72% length of fourth, fourth ray reaching posteriorly to between bases of anal rays 3—5. Lateral scales 23; anterior transverse scales 8; posterior transverse scales 7; predorsal scales 5– 6 (mean = 5.9), anteriormost cycloid, others ctenoid; no scales on cheek; opercle with 1 row of 2 ctenoid scales; pectoral base with 2 vertical rows of cycloid scales with 2 scales in posterior row, dorsalmost of which is much enlarged and covers most of fin base; 6 –7 prepelvic scales (in midline anterior to basal membrane), middle scales in series may be ctenoid; 12 circumpeduncular scales; body scales ctenoid except for cycloid scales on anterior belly midline, and beneath pectoral fin base; body scales extending anteriorly to just behind eye. Gill opening extending anteroventrally to a vertical below mid- to post-pupil. Teeth not examined in detail, but appear to be typical of other Trimma . Cephalic sensory papillae ( Fig. 4 ) row counts given in Table 1 . Tongue broadly truncate with rounded edges, may have a central tip (}-shaped). Gill rakers on first arch 2 –3 + 10 –13 = 12 –16 (means = 2.6 + 11.7 = 14.3). Anterior nasal opening a short tube, posterior nasal opening a pore with a raised rim, both protruding from slightly raised oval sac confined to anterior half of snout. Bony interorbital 66– 77 –79% pupil width, with a slightly convex ridge between interorbital papillae and no postorbital groove. No ridge of tissue (or dermal crest) extending anterior to first dorsal spine. Epaxialis extending anteriorly to above a vertical with posterior margin of pupil. Vertebral transition not examined, but predicted to be Type B (see Winterbottom, 2011, for definitions).

Colour pattern (live, from four images of specimens from Fakfak and Penemu Is.). The holotype, a 14.0 mm SL female from Fakfak ( Fig. 5 A) has a purplish-red snout and cheek, lighter dorsally. There are eight red stripes along the body behind the eye, approximately half-pupil in width, and separated anteriorly by eight grey stripes (the dorsalmost in the midline), equal in width anteriorly. The grey stripes gradually taper out posteriorly, the longest being the one along the mid-lateral scale row which ends about half-way along the caudal peduncle, which is an almost uniform reddish-yellow. The dorsalmost red stripe connects with its antimere across the midline above the posterior margin of the pupil. The dorsal fins have a half pupil diameter dark basal stripe made up of iridocytes and dark brown chromatophores, and a similar stripe (lacking iridocytes) is present at the base of the anal fin. Just distal to these stripes, both fins have a red stripe of similar width. The remainder of the fins are hyaline with scattered brown chromatophores, more thickly scattered in the anal fin than the dorsal fins. The unbranched caudal fin rays also have a fairly dense scattering of dark chromatophores, but the rest of the fin is hyaline with orangeyellow fin rays. Brown chromatophores are scattered along the rays of the pectoral and pelvic fins; the membranes are hyaline. A light coloured spot is present on the upper base of the pectoral fin, and another is present at the posterodorsal coner of the opercle. The iris is bright red with a thin, pure white band around the margin of the pupil. A second specimen from the same collection as the holotype ( Fig. 5 B, ROM T12762, 12.9 mm SL) appears to have had many of the body scales abraded off. The lines on the body are orange, and appear largely in a zig-zag pattern, the stripe in the dorsal and anal fins distal to the basal stripe is orange rather than red, and the red body colour grades to yellow on the peduncle. In addition to iridocytes in the basal stripe of the dorsal fin, they are present in the basal and distal portions of the anal fin and along the unbranched caudal fin rays, which are yellow rather than orange. A 15.6 mm SL female from Penemu Is and a 12.5 mm SL male from Fakfak ( Figs. 5 C and 5 D, ROM 94899 and 95784 respectively) are very similar to the holotype, but the white circle around the pupil has a thin black outer rim.

Colour pattern in alcohol: Background colour pale straw yellow to white, and all traces of red and yellow have disappeared. The grey stripes are present, either as continuous lines made up of brown chromatophores and melanophores, or consisting of square to rectangular blocks of pigment cells separated by thin irregular white bars (cf. Fig. 6 A and B).

Comparisons. Trimma pajama belongs to a limited grade of four described species which lack an elongate spine in the first dorsal fin, have a scaled predorsal midline, no cheek scales, a scaled opercle, only unbranched pectoral fin rays, and a fifth pelvic fin ray that is branched once dichotomously. The described species are: Trimma annosum Winterbottom, 2003 , T. emeryi Winterbottom, 1985 , T. flavicaudatum ( Goren, 1982) , and T. fucatum Winterbottom and Southcott, 2007 . All these species have more pectoral fin rays (16–18 vs. 12–14), and all but T. flavicaudatum have a narrower bony interorbital region that forms a steep-sided trench (<50% pupil width, vs.> 66% with no trench). None of the four species possesses red to orange stripes alternating with dark stripes on the body as seen in T. pajama , and, although T. flavicaudatum does have a yellow caudal peduncle in life, the body is very dark with scattered red spots, and the head has several almost pupil diameter red spots (vs. striped body with no spots on head). Trimma striatum ( Herre, 1945) and T. capostriatum (Goren, 1981) are the only other species in the genus with stripes, but in these species the stripes are confined to the region anterior to the base of the first dorsal fin. Neither of these species have scales in the predorsal midline (vs. such scales present).

Distribution. Trimma pajama is currently known from specimens from Raja Ampat and the Fakfak Peninsula of West Papua, Indonesia, and the Milne Bay district, Papua New Guinea from depths of 3– 10 m. There are also photographs and/or specimens of what may be this species from Kalimantan, Indonesia, Palau, the Hermit Is of Papua New Guinea, and the Solomon Is.

Etymology. The name is derived from the Hindi word “ pajama ” (= pājāma ), loose clothing worn when retiring for the night, in allusion to the contrasting stripes so common in at least the British version of that garment. The name is to be treated as a noun in apposition. This species has been informally referred to as Trimma RW sp. 70.

Discussion. Live and freshly collected specimens from Palau and the Solomon Islands differ from those described above in having i) the dark grey stripes on the body are almost white; ii) the red body stripes are much darker, being brick red (live, Solomons) to red-brown (collected specimens, Solomons and Palau); and iii) the inner ring of the iris is wider and yellow (rather than white). Given recent studies using the Cytochrome Oxidase 1 gene (Winterbottom et al., 2014) suggesting that morphology may only be distinguishing about half the genetic species of this genus, and that more than one exceedingly similar morphological species can be found in the same general area (and even in the same collection), we prefer to err on the side of caution in selecting type specimens, and accordingly have restricted the types to specimens from Raja Ampat and the Fakfak peninsula. It seems quite possible that more than one species is present in the samples and photographs from other areas available to us. Sequences for the mitochondrial gene CO1 have been deposited in GenBank under Accession Number KJ624418 .

Trimma pajama appears to be restricted to relatively shallow (3–10 m) reef areas protected from wave exposure, and all type specimens were collected exclusively from within beds of Halimeda macroalgae growing beneath branching Acropora coral stands. This is the only species of the genus we are aware of to be limited to this habitat.

Figures

FIGURE 4. Cephalic sensory papillae of T. pajama, 14.0 mm SL female holotype, ROM 94175, Fakfak Peninsula, West Papua. A: left lateral view. B: dorsal view. Photos by R. Winterbottom.

FIGURE 5. Left lateral views of freshly collected T. pajama. A: 14.0 female holotype, ROM 94175, Fakfak Peninsula, West Papua. B: 12.9 mm SL paratype, ROM T 12762, Fakfak Peninsula, West Papua. C: 15.6 mm SL female paratype, ROM 94899, Penemu Is West Papua. D: 12.5 male paratype, ROM 95784, Penemu I., West Papua. Images C D reversed. Photos: M. V. Erdmann.

FIGURE 6. Left lateral views of body pigmentation of preserved specimens of T. pajama. A: 14.0 female holotype, ROM 94175, Fakfak Peninsula, West Papua. B: 15.0 male paratype, ROM 94899, Penemu Is., West Papua. Photos: R. Winterbottom.