Trimma kardium, Winterbottom, Richard, Erdmann, Mark V. & Dita Cahyani, N. K., 2015

Winterbottom, Richard, Erdmann, Mark V. & Dita Cahyani, N. K., 2015, New species of Trimma (Actinopterygii, Gobiidae) from Indonesia, with comments on head papillae nomenclature, Zootaxa 3973 (2), pp. 201-226 : 210-217

Trimma kardium sp. nov.

Heart pygmy goby

Figs. 7–11 , 18

Material examined. Five lots, five specimens (12.0– 16.7 mm SL), description excludes data from ROM T 012726 (tissue specimen), all from the West Papua province of Indonesia.

Holotype. ROM 98815, (16.7), Kaimana, Triton Bay, White Rock Falls, (03°53.757'S, 134°06.638'E), 50 m, clove oil, field number: MVE-14-018, 3 Dec., 2014, M.V. Erdmann.

Paratypes. MZB 22714, (12.0, ex-ROM 936491), Teluk Cendrawasih, Pulau Mansinam, (00°55.344'S, 134°06.557'E), 70 m, clove oil, 20 Mar., 2012, M.V. Erdmann. ROM 87545, (15.8), Raja Ampat, Keruo I., (00°35.269'S, 130°17.685'E), steep slope with overhangs sand/gorgonians, 70 m, clove oil, 27 Aug., 2010, M.V. Erdmann. ROM T 012726, (12.2), Raja Ampat, Keruo I., (00°35.269'S, 130°17.685'E), steep slope with overhangs sand/gorgonians, 70 m, clove oil, 6 Dec., 2010, M.V. Erdmann. ROM 88107, (13.8), Raja Ampat, off Misool I., Pulau Fiabacet, (02°13.196'S, 130°33.834'E), clove oil, 26 Oct., 2010, M. V. Erdmann.

Diagnosis. A species of Trimma with a narrow bony interorbital (≤40% pupil width), a moderate interorbital trench with a slight groove posterodorsal to the eye, 17–18 unbranched pectoral fin rays, 1–5 cycloid scales in the predorsal midline confined to about the middle third of the distance between the posterodorsal margin of the eye and the base of the spine of the first dorsal fin, and a single row of 1–3 cycloid scales along the upper border of the opercle. In live and freshly collected specimens of this species, the presence of oval red hyoid spots connected anteriorly in the midline is diagnostic.

Description. Based on the holotype and an additional three specimens (12.0– 16.7 mm SL). Dorsal fins VI + I 9, second or third spine longest but not elongate, and reaching to between base of first to second elements of D2 when adpressed, first ray of second dorsal fin branched (unbranched in holotype), posterior element of last dorsal ray unbranched, last ray reaching posteriorly 55– 64 % (mean = 59.0%) of distance between its base and first dorsal procurrent caudal ray; anal fin I 8– 9, first ray unbranched, as is posterior element of last ray, which reaches posteriorly 40– 48 –54% (mean = 47.3%) distance between its base and first ventral procurrent caudal ray; pectoral fin 17– 18 (mean = 17.8), all rays unbranched, fin reaching posteriorly to a point above first to third anal fin element; pelvic fin I 5, first four rays with one sequential branch, fifth ray unbranched ( Fig. 7 A) or branched (n = 1, Fig. 7 B) and 52 –60% the length of fourth (mean = 56.5%), fourth ray reaching posteriorly to a point between bases of third to sixth anal elements; no fraenum; basal membrane varies from vestigial (perhaps torn) to 11 –15% length of fourth ray ( Fig. 7 B). Lateral scales 23; anterior transverse scales 8– 9 (mean = 8.5); posterior transverse scales 7– 8 (mean = 7.3); median predorsal scales 1 –5 (mean = 2.8; Fig. 8 ); scaled midline area confined to about middle third of nape with naked areas anteriorly and posteriorly; scales extending anteriorly on sides of nape to just behind eye; scales on cheek apparently absent; opercle with single row of 1–3 cycloid scales; pectoral-fin base margined posteriorly with 2– 3 vertical rows of cycloid scales with 4 scales in outer row, 3 in row anterior to this, and 1 in anterior-most row (if present, holotype only); scales anterior to pelvic fin 4– 6 (mean = 4.8), scales on and immediately behind pectoral-fin base, breast, anterior midline of belly, and midline of nape cycloid, scales on sides of nape may be ctenoid or cycloid, other scales ctenoid. Upper jaw teeth with an outer row of about 6 evenly spaced, curved, enlarged canines decreasing in size posteriorly and extending to bend of premaxilla, inner row of about 4 straight conical teeth about one-third size of outer row, ending before bend of premaxilla, 2–3 irregular rows of small conical teeth between these, grading to single row on posterior part of premaxilla. Lower jaw teeth with outer row of about 6 evenly spaced, curved, enlarged canines ending at bend of dentary, inner row of slightly enlarged and curved teeth decreasing in size posteriorly to end at beginning of coronoid process, 2–3 irregular rows of small conical teeth between these, grading posteriorly to single row ending near anterodorsal tip of coronoid process of dentary. Tongue teretely rounded to weakly bilobed. Gill opening extending anteroventrally to below mid- to posterior third-pupil; outer gill rakers on first gill arch 3 –4 (mean = 3.3) + 13– 14 (mean = 13.5), total rakers 16– 17 (mean = 16.7). Anterior naris a long thin tube extending well past upper lip, almost equal in length to width of nasal capsule, which is confined to anterior half of snout; posterior naris a pore with raised rim, separated from eye by 2.5 –3 times its diameter ( Fig. 9 ). Bony interorbital width 34 –40% of pupil diameter in width (mean = 38.0%), interorbital with moderately developed ‘U’-shaped trench about as wide as deep, a shallow postorbital groove but not trench-like. Sensory papillae as in Figure 9 , number of papillae in each row given in Table 1 . Ridge of tissue (or dermal crest) may extend anterior to first dorsal spine for one-third distance to interorbital ( Fig. 8 A, red arrows). Epaxialis extending anteriorly to above a vertical with posterior margin of pupil. Abdominal/caudal vertebral transition not examined, but presumed to be Type B.

Colour pattern, freshly collected, based on images of holotype, 16.7 mm SL male, ROM 98815, Fig. 10 A, and paratype, 12.2 mm SL, ROM T 012726, Fig. 10 B. Holotype with head light purplish-grey, grading into light yellow behind eye, along dorsal margin of opercle and across posterior margin of opercle (where suffused with pale red), light pink lips, upper branchiostegal membrane and pectoral fin base, cheek with scattered iridocytes and darker pigment cells; ovoid bright red spot with diffuse dark pigment cells centrally over hyoid arch on ventral surface, tapering anteriorly where joined at midline below hypohyals, diverging slightly from midline posteriorly ( Fig. 11 A). Iris with dark blue border and thin, sandy-yellowish halo around pupil, middle portion reddish with darker diffuse stripe above pupil. Nape and body greenish yellow dorsally, becoming less green below midlateral septum, posterior margins of scales slightly darker, especially on anterodorsal half of body, some scattered dark chromatophores present, especially anteriorly. First dorsal fin with half-pupil diameter basal yellow stripe, fin membrane above this hyaline with numerous scattered iridocytes. Second dorsal fin with narrow dark basal stripe followed by yellow stripe (in line with stripe of first dorsal fin), membrane above this with iridocytes, fin rays pinkish. Anal fin mostly yellow, margined by distal stripe of iridocytes and dark pigment cells. Caudal fin yellow, somewhat paler distally. Pectoral fin rays yellow, membrane hyaline. Pelvic fin rays off-white, scattered iridocytes in membrane. Paratype similar ( Fig. 10 B), but snout, jaws and anterior cheek red, middle ring of iris mix of red and yellow, no darker stripe above pupil, scale pockets on side of nape outlined with darker pigment, breast and lower pectoral fin base orange and numerous iridocytes on belly.

Preserved colour. Holotype pale straw-yellow, cheek and opercle with heavy scattering of dark chromatophores, sides and top of snout covered with small round chromatophores with some scattered on lips, nape with scattered melanophores and larger brown chromatophores, which decrease in concentration along dorsum to end of second dorsal fin, and tend to be concentrated along posterior margins of scales. Diffuse hyoid spot made up of brown chromatophores on branchiostegal membrane beneath hypohyals and below posterior half of eye ( Fig. 11 B). Base and distal half of first dorsal fin hyaline, with stripe of dark chromatophores between; thin dark basal stripe in second dorsal fin followed by clear stripe and then another diffuse dark stripe before becoming hyaline distally; anal fin with similar basal and distal dark stripes, middle of fin hyaline; caudal fin hyaline with few scattered dark chromatophores (especially on ventral procurrent fin rays); pectoral fin hyaline; pelvic fin with some dark chromatophores along margins of rays. Paratype similar, but with dark chromatophores on nape and anterior body more strongly associated with scale pockets, and no trace of hyoid spot.

Etymology. Named for the Greek ‘kardia’, a heart, in allusion to the two ovoid red spots that are joined anteriorly on the ventral surface of the head, and have an admittedly tenuous stereotypical resemblance to that organ when viewed from below. This species has been informally referred to as Trimma RW sp 98.

Distribution. Currently know from 5 specimens collected in 50–70 m at Raja Ampat, Cendrawasih Bay and Triton Bay, all in the province of West Papua, Indonesia ( Fig. 18 ).

Comparisons. Most species of Trimma either have a scaled or a naked predorsal midline. However, several species exhibit variation in this region. A few (<6%) specimens of T. maiandros Hoese et al., 2011 , may have 1–5 scales in the middle of the nape as in the present species. That species lacks opercular scales (vs. present), has a dark zig-zag stripe on the nape and dorsal half of the body separated by yellow blotches, which are also present on the nape and cheek (vs. such markings absent), and lacks the red hyoid spots (vs. present). Some specimens of Trimma anthrenum Winterbottom, 2006 , may have reduced predorsal scalation with naked areas in front of the first dorsal spine and immediately behind the eye. Trimma anthrenum has at least some branched pectoral fin rays (vs. unbranched), and lacks scales on the opercle and the red hyoid spot (vs. both present). A few large specimens (> 20 mm SL) of T. erdmanni Winterbottom, 2011 , have up to 6 scales in the midline of the central portion of the predorsal area, but may be differentiated by the presence of branched pectoral fin rays, a red lateral stripe on the body (vs. both absent) and by the lack of the red hyoid spots. Trimma hoesei Winterbottom, 1984 , has a few scales in the predorsal midline, but these are confined to the area just anterior to the first dorsal fin spine (vs. middle of the nape), there are branched pectoral fin rays (vs. unbranched), no opercular scales (vs. present) and the caudal fin is forked (vs. rounded). Trimma okinawae ( Aoyagi, 1949) and T. readerae Winterbottom & Hoese, 2015 may have 3– 5 scales across the midline of the nape anterior to the first dorsal fin spine, and additionally may have a red spot on the branchiostegal membranes. However, these two species have branched rays in the pectoral fin (vs. unbranched), lack opercular scales (vs. present) and the red spot on the branchiostegal membranes are smaller, situated more posteriorly (just below the vertical limb of the preopercle and posterior to the point where the branchiostegal membranes join in the midline), and do not join anteriorly in the midline. Trimma irinae Winterbottom, 2014 also has a dark red spot on the branchiostegal membranes, but has a fully scaled predorsal midline (vs. partially scaled) an elongate second dorsal spine (vs. not elongate), branched pectoral fin rays (vs. unbranched) and two black spots near the base of the first dorsal fin (vs. absent). Trimma hayashii Hagiwara & Winterbottom, 2007 has a dark ocellated spot on the branchiostegal membranes, but its position is the same as that in T. okinawae and T. readerae above (vs. anterior to the junction of the membranes). It also has some pectoral fin rays branched (vs. unbranched), lacks opercular scales (vs. present) and has red spots on the head and nape (vs. spots absent).

Discussion. Specimens examined for this study were collected between 50–71 m, where they were invariably collected living associated with larger coral rubble pieces lying on soft bottoms below the reef slope. Unlike most species of Trimma , this species appears to live a solitary existence, and only single specimens were collected at any given time. The species seems to have a similar behaviour to T. meranyx Winterbottom et al., 2014a , which cooccurs with this species and has a similar depth distribution. Other deep-dwelling Trimma that also are generally found individually include T. zurae Winterbottom et al., 2014a and T. irinae .

Phenetically, the single specimen of this species available for genetic analysis forms a grade with an undescribed species from Fiji (T. RW sp 97) and three haplogroups of T. stobbsi according to the CO1 analysis of Winterbottom et al. (2014b).

Figures

FIGURE 7. Trimma kardium, ventral view of pelvic fin area to show basal membrane (left arrow) and fifth pelvic fin ray (right arrow). A: ROM 93649, 12.0 mm SL. B: ROM 88107, 13.8 mm SL. Specimen stained with cyanine blue. Photos by R. Winterbottom.

FIGURE 8. Trimma kardium, dorsal view of anterior half of body to show predorsal scalation and extent of nuchal crest (red arrows in A). A: ROM 98815, 16.7 mm SL. B: ROM 87545, 15.8 mm SL. Specimen stained with cyanine blue. Photos by R. Winterbottom.

FIGURE 9. Trimma kardium, disposition of head papillae, ROM 87545, 15.8 mm SL. A: lateral view. B: dorsal view. Red arrows in B point to anterior and posterior nares respectively. Specimen stained with cyanine blue. Photos by R. Winterbottom.

FIGURE 10. Trimma kardium. Left lateral view of: A: freshly collected holotype, ROM 98815, 16.7 mm SL male, Triton Bay; B: freshly collected paratype, 12.2 mm SL, ROM T 012726, Keruo Island (image reversed). Photos by M. V. Erdmann (A) and G. R. Allen (B).

FIGURE 11. Trimma kardium, ventral view of head of holotype, ROM 98815, 16.7 mm SL male, Triton Bay. A: freshly collected. B: preserved. Photos by M. V. Erdmann (A) and R. Winterbottom (B).

FIGURE 18. Distribution of the three new species based on material examined for this study. Trimma aturirii, black inverted triangles. Trimma kardium, black diamonds. Trimma trioculatum, coloured pentagons. Blue fill, type locality, Group 1 haplogroup; green fill, Palau, Group 2 haplogroup; yellow fill, Rabaul, New Britain, Group 3 haplogroup; red fill, unknown haplogroup.