Trimma burridgeae Winterbottom, 2016, n.sp.
Creators: name: Winterbottom, Richard
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Gobiidae
Trimma
Trimma burridgeae

description: Trimma burridgeae n.sp.
Mary’s Pygmygoby
Figs. 11, 19–23, 31
Trimma tevegae: (non Cohen & Davis, 1969:321)—Winterbotton et al., 2014:88 (Group 5 only)
Material examined. All type specimens collected in Hatohobei State, South West Islands of Palau. The description is based primarily on up to 28 specimens, (16.4–24.7 mm SL) from Helen Reef (plus one specimen from Tobi Id). Additional material is from the main group of islands of Palau.
Holotype. ROM 100153, (21.1 mm SL male, Helen Reef, southern margin near E end, 02°47'56" N, 131°45'20" E, huge cave (ca. 15 m wide, 4 m high) and surrounding area with sand/silt floor at 27 m, hydroids, some hard coral, sea fans, sponges, ascidians, 24–32 m, rotenone, 23 Sep., 2008, R. Winterbottom et al.
Paratypes. ROM 83066, (26.6), off southern-most tip of fringing reef of Tobi Id, good hard corals (Acropora, Pocillopora, plate coral), hydroids in caves, sponges, 02°59'50" N, 131°07'23" E, 16–28 m, rotenone, 15 Sep., 2008, R. Winterbottom et al. ROM 83215, (19.6), Helen Reef, at marker buoy on W side of 'no take' zone in middle of lagoon, some live coral (lettuce, Acropora, Seriatopora), a few soft corals, 02°52'47"" N, 131°46'30 E, 15–28 m, rotenone, 19 Sep., 2008, R. Winterbottom et al. (plus T04002). ROM 83255, 27(7.2–17.2), Helen Reef, steep (80°) outer reef slope along SE edge, sea fans, hard corals (variety), soft corals (Nephytes), many small caves with hydroids in overhangs, 02°49'40" N, 131°47'18" E, 20–35 m, rotenone, 22 Sep., 2008, R. Winterbottom et al. (plus T04035). ROM 83273, 2(19.5–19.6), Helen Reef, south end 'embayment', vertical drop-off from reef top (no reef slope), sponges, hydroids, sea-fans, ascidians, some small heads of hard corals, 02°47'57.1" N, 131°45'18.2" E, 22–34 m, rotenone, 22 Sep., 2008, R. Winterbottom et al. (plus T04043). ROM 83298, 18(17.1–21.0), collected with the holotype (plus T04055–04056). ROM 83321, 4 (8.7–19.9), Helen Reef, S coast near E point, lots of hard and soft corals, some sea fans, sponges, 02°47'58" N, 131°45'17" E, 12–30 m, rotenone, 24 Sep., 2008, R. Winterbottom et al. ROM 83332, (21.0), Helen Reef, W side, about 0.75 km south of channel entrance, wide variety of hard corals, some sea-fans and sea whips, Millepora, sponges, ascidians, 02°51'47" N, 131°43'48" E, 10–30 m, rotenone, 25 Sep., 2008, R. Winterbottom et al. ROM 83350, (17.2), Helen Reef, NW outer reef about 0.5 km S of northern large ship wreck, NW of N tip of island in lagoon, huge variety of hard corals (Acropora, Pocillopora, cactus, star, lettuce corals), a few hydroids, soft corals, some encrusting algae, 02°58'38" N, 131°47'59" E, 7–33 m, rotenone, 27 Sep., 2008, R. Winterbottom et al. ROM 83371, 6(16.3–20.6), Helen Reef, S coast at W side, lots of hard corals, some sea-fans, sponges, hydroids, 02°48'08" N, 131°43'53" E, 23–36 m, rotenone, 28 Sep., 2008, R. Winterbottom et al.
Additional (non-type) material. ROM 70729, 3 (20.0–28.7), Uchelbeluu Reef east of Koror Id, 07°16'41" N, 134°31'44" E, 91.4 m, quinaldine, 12 May, 1997, J.L. Earle & R. Pyle. ROM 70730, 4 (16.7–22.4). Uchelbeluu Reef east of Koror Id, 07°16'41" N, 134°31'44" E, 91 m, quinaldine, 10 May, 1997, J.L. Earle. ROM 74794, 21 (12.6–20.6), Koror State, SE of Koror Id at SW corner of Uchelbeluu Reef (aka the Short Drop-off), hard corals (Acropora, Montipora), hydroids, 07°16'28.7" N, 134°31'32.1" E, 13.7–25.9 m, rotenone, 21 May, 2004, R. Winterbottom et al. ROM 74796, 6 (14.3–22.8), Koror State, S of Shark City, W side of Koror, south of Ulong Pass, antipatherians, numerous small hard corals, 07°14'41.3" N, 134°12'05.0" E, 30.5–42.7 m, rotenone, 11 Jun., 2004, R. Winterbottom et al. ROM 74888, 11 (12.8–23.2), off SE coast of Koror I., SW corner of Uchelbeluu Reef, corals and hydroids, 07°16'26.9" N, 134°31'29.3" E, 12.2–21.3 m, rotenone, 20 May, 2004, R. Winterbottom et al. ROM 76100, 13 (6.9–19.0), Koror State, outer reef off Ulong pass N of Ngerumekaul Pass, hydroids, sea fans, various hard corals, Favea, 07°18'11.2" N, 134°14'06.2" E, 15.2–30.5 m,. rotenone, 26 May, 2004, R. Winterbottom et al. ROM 76414, 10 (10.8–20.1), Koror State, just N of pass to W of Ulong Id, outer reef, some gorgonians, Acropora, Pocillopora, sponges, 07°17'44.2" N, 134°14'18.9" E, 18.3–30.5 m, rotenone, 7 Jun., 2004, R. Winterbottom et al. ROM 80024, 2 (20.9–23.1), Babeldaob Id, off west coast at " The Channel ", 07°32'32.0" N, 134°28'03.1" E, 12 m, quinaldine, 30 Mar., 2006, P. Colin. ROM 80305, 2 (15.8–18.2), Pelilieu State, off west coast of Pelilieu Id, steep (80 degree) drop-off slope with a few caves and recesses, some coarse sand, coral rock, 7°01'12.9" N, 134°13'51.5" E, 27–41.5 m, rotenone, 12 Apr., 2006, R. Winterbottom et al. ROM 80312, 2 (19.2–22.5), Koror State, west coast near Blue Corner, steep coral covered slope below reef crest on outer reef, 07°10'13.0" N, 134°13'18.2" E, 12–25.9 m, rotenone, 22 Mar., 2006, R. Winterbottom et al. ROM 80321, (17.0), Koror State, lagoon, west side about 1 km east of reef top, consolidated bommie about 20m in diameter and reaching to within 3m of surface surrounded by fine white sand, 7°12'35.0" N, 134°13'42.3" E, 0–6.7 m, rotenone, 22 Mar., 2006, R. Winterbottom et al. ROM 80325, 2 (12.2–16.0), Pelilieu State, off west coast of Pelilieu, outer reef, 50° slope, scattered limestone and coarse shell sand, 07°01'03.5" N, 134°13'35.3" E, 36.6–45.7 m, rotenone, 24 Mar., 2006, R. Winterbottom et al. ROM 80363, 3 (16.9–21.0), Koror State, Uchelbeluu Reef, overhang in steep reef slope, 07°16'24.8" N, 134°01'26.6" E, 17.4 m, quinaldine, 29 Mar., 2006, P. Colin. ROM 80400, 3 (17.3–20.3), Anguar State, west coast of Anguar a little south of northern shore, almost vertical reef with caves, ledges, some sand, vertical cleft, 6°54'45.0" N, 134°07'38.3" E, 33.5–44.2 m, rotenone, 0 1 Apr., 2006, R. Winterbottom et al. ROM 80417, 9 (8.7–18.6), Koror State, north of Ulong Pass, western reef, 80° outer reef slope, small caves, sand, 7°18'18.0" N, 134°13'59.9" E, 24.4–36.6 m, rotenone, 4 Apr., 2006, R. Winterbottom et al. ROM 93074, 21 (12.8–21.4), off SE coast of Koror Id, Uchelbeluu Reef near east tip, drop-off wall and steep gully with sand, numerous small caves, overhang and crevices, 07°16'29.2" N, 134° 31' 32.0" E, 19.8–27.4 m, rotenone, 31 Mar., 2006, R. Winterbottom et al. ROM 95422, 25 (13.9–24.4), off SE coast of Koror Id, SW corner of Uchelbeluu Reef, drop-off wall, hydroids, sea fans, variety of hard corals, 07°16'54.3" N, 134°31'38.7" E, 15.2–26.5 m, rotenone, 28 May, 2004, R. Winterbottom et al. ROM 1915CS, 4(18.2–19.8), collected with ROM 93074. ROM T00612– T00613, Koror State, due west of Eleven Islands, almost vertical slopes, coral/limestone interspersed with course (shelly) sand on outer reef, 7°11'08.1" N, 134°12'56.0" E, 33.5–44.5 m, rotenone, 23 Mar., 2006, R. Winterbottom et al. ROM T03745, Koror State, Uchelbeluu Reef, 7°15' N, 134°31.5' E, 50 m, quinaldine, 10 May, 2007, P. Colin.
Diagnosis. A species of Trimma with a bony interorbital 80–100% pupil diameter, 11 scales in predorsal midline with the anterior few rows often cycloid in adults, a second dorsal spine that reaches to between the middle and the end of the second dorsal fin or just beyond this point, normally four free neuromasts (sensory papillae) in row f on the chin and in row r on the top of the snout, usually 14 unbranched pectoral-fin rays, and an unbranched fifth pelvic-fin ray that is 47–63% the length of the fourth ray. Freshly collected specimens have a red to yellow background colour with a light stripe along the mid-lateral body that continues forward over the top of the pupil, a light stripe below the eye bordered dorsally by a narrow red stripe (both light stripes apparently blue in life) and a broad diffuse internal dark stripe over the abdominal cavity which narrows and continues posteriorly on and just below the vertebral column, ending at the pale bar in front of the dark caudal blotch.
Description. The description is based on up to 28 specimens, 16.4–24.7 mm SL (mean 19.5) from six collections from Helen Reef and one from Tobi Id, South West Islands, Palau. Dorsal fin VI + I 8 (once I 9, n = 28), second spine variably elongated, reaching to base of last ray of second dorsal fin on average, but adpressed tip of spine to between base of fourth ray of second dorsal fin to sixth scale behind last dorsal ray base, (Table 1, see Discussion for details of sexual dimorphism in length of spine), all fin rays branched except for posterior element of last (first dorsal ray unbranched in one specimen), third spine slightly elongated, reaching to between just anterior to spine of second dorsal fin and base of third fin ray (mean value to between spine and base of first ray), last ray 40– 78 % (mean 56.2%, n = 20) of distance between its base and first dorsal procurrent caudal fin ray; anal fin I 8 (n = 28), first ray usually branched (unbranched in 4), last ray 31– 57 –68% (mean 47.4, n = 19) of distance between its base and first ventral procurrent caudal fin ray; pectoral fin 13– 14 (mean 13.9, n = 28), rays usually unbranched (1 and 3 branched rays in one specimen each), reaching posteriorly to vertical line above urogenital papilla to base of second element of anal fin; pelvic fin I 5, fifth ray unbranched and 47– 51 –63% (mean 55.2%, n = 25) length of fourth ray, which reaches posteriorly to between bases first to third element of anal fin, pelvic rays 1–4 with a single sequential branch point; basal membrane restricted to fold across midline beneath last prepelvic scale or attached to sides of body near midline; no fraenum. Lateral scales 23 –24 (mean 23.0, n = 22); anterior transverse scales 8 –10 (mean 9.2, n = 21); posterior transverse scales 7 –9 (mean 8.0, n = 21); predorsal midline scales 11 (once 10, n = 18) with up to first three anteriormost scale rows cycloid, but may all be ctenoid in specimens> 18 mm SL, other scales on nape ctenoid, scales rimming orbit a mix of mostly cycloid with some ctenoid (especially in larger specimens,> 19 mm SL), scales reaching anteriorly to above anterior to middle of pupil; cheek with three rows of cycloid scales, uppermost row of 1– 2 –3 scales (mean 1.4, n = 20), row below it of 7 –8 scales (mean 7.7, n = 20), ventralmost row of 1– 3 –5 scales (mean 2.2, n = 20); opercle with four (twice three) horizontal rows of scales, often with 1–2 very small supernumerary cycloid scales dorsally, larger, more central scales usually ctenoid, others cycloid (Fig. 19), dorsalmost row with 2–4 scales (mean 3.0, n = 6), second row 2–3 (mean 2.8, n = 6), third row 2–3 (mean 2.2, n = 6), ventralmost row if present of 2 (n = 2); pectoral base with 2 –3 vertical rows of cycloid scales, with 1–3 in anterior row (if present, mean 1.8, n = 6), 2– 3 – 4 in next row (mean 2.9, n = 12), and 4 in outer row (n = 12); 6 –8 rows of cycloid prepelvic scales along midline (mean 6.9, n = 17); area between pelvic spine and ventral margin of pectoral fin base and midline of belly just behind pelvic fin base with cycloid scales, those adjacent to bases of dorsal and anal fins ctenoid. Upper jaw with outer row of closely spaced, curved conical teeth, decreasing slightly in size and curvature posteriorly, reaching almost to posteroventral tip of premaxilla; about 3 irregular rows of small, conical, slightly curved inner teeth at symphysis reducing to single row at about middle of premaxilla which continues almost to proximal tip of premaxilla, innermost row slightly enlarged near symphysis and directed posteriorly. Lower jaw with outer row of about 5–7 enlarged, slightly curved, spaced canines ending at bend in dentary, 1–2 irregular rows of smaller, conical, slightly curved teeth at symphysis grading into single row to anterodorsal tip of coronoid process of dentary, teeth at bend of dentary may be somewhat enlarged (description of teeth based on cleared and stained material). Tongue rounded to truncately pointed. Gill opening extending anteroventrally to below mid-pupil; gill rakers 3– 4 + 15– 16 –17 = 19– 20 –21 (mean 3.5 + 16.1 = 19.6, n = 27). Anterior nares a short tube reaching anteriorly to above anterior margin of upper lip, posterior opening pore-like with raised rim, separated from bony front of orbit by 2 –2.5 times its diameter, nasal sac raised and on anterior one-third of snout. Bony interorbital 80– 86 –100% (mean 91.9%, n = 17) pupil diameter; shallowly concave with slight median fleshy ridge forming broadly rounded W in cross section; epaxialis extending anteriorly to point above posterior of pupil. Caudal peduncle depth as percentage caudal peduncle length 34.2–45.3 (mean 39.7, n = 16); head length as percentage SL 29.9–34.4 (mean 31.3, n= 24); as percentage head length, horizontal eye diameter 31.9–36.2 (34.0, n = 24); snout length 21.0–26.9 (mean 23.5, n = 24), cheek depth 10.8–18.5 (mean 13.9, n = 24). Cephalic sensory papillae as in Fig. 20, number of papillae in each row given in Table 2, occasional supernumerary papillae may be present. In addition, papillae in row p at positions 3 and 5 (from anteriormost papilla) and in row 2 below eye (Winterbottom, 2011, Fig. 2 B) may be augmented by one additional papilla to form transverse series in row p and vertical series in row 2. At position 3 of row p, extra papillae present in 2 specimens (unilaterally, see left side, Fig. 20 B, red arrow, and 4 specimens bilaterally), at position 5 in 5 (including holotype) and 7 specimens respectively, and in row 2 (see Fig. 20 A, red arrow) in 6 (including holotype) and 3 specimens respectively (n = 27 specimens for row p and 28 specimens for row 2). Overall, 10 of 28 specimens possessed extra papillae in one or more positions on at least one side of body, although no specimens exhibited extra papillae at all three positions. Abdominal/caudal vertebral transition Type A, with haemal arches of first two caudal vertebrae expanded (based on cleared and stained material).
Colour pattern. Freshly collected. (No images of live specimens available, descriptions based on photos of 16 freshly collected individuals from both island groups, including 5 tissue specimens from Helen Reef). Colour somewhat variable. Background brownish-orange in 17.2 mm SL female (Fig. 21 A), with half-pupil width lighter stripe from upper eye margined dorsally with brick red and curving along scale row above midlateral line to end in front of large (eye diameter) black blotch on dark red background covering posterior peduncle and anterior bases of caudal fin rays. Light stripe irregularly expanded just anterior to blotch, more so dorsally than ventrally, to form vague light bar across peduncle. Stripe continues anteriorly across orbit as dark blue to black stripe above pupil. Dorsal part of body above stripe with numerous rounded dark chromatophores, especially along scale margins; indistinct dark red line along bases of elements of dorsal fins. Abdomen with numerous large, amorphous and very dark subdermal chromatophores, becoming more concentrated above anal fin before decreasing in number along peduncle. Top of snout dark, with numerous melanophores. Chin, cheek, lower part of opercle, breast and lower abdomen almost white, with some scattered xanthophores and erythrophores, demarcation on head fairly abrupt just below eye and across distal ends of jaws, distinctly margined with red just below eye. Dorsal fin elements reddish, membranes without much pigment except for yellow blush at posterodorsal end of second dorsal fin, bases of caudal rays red (as part of caudal blotch), some scattered small black pigment cells in membrane, especially towards tips of rays. Anal fin with some small scattered xanthophores, pelvic and pectoral fins hyaline, pectoral rays reddish. Iris yellow with many amorphous melanophores, especially anteriorly, dorsally and posterodorsally. A 17.2 mm SL male (Fig. 21 B) basically similar, but more yellow-brown in background colour. Light lateral stripe bordered by thin brick-red line both dorsally and ventrally, red stripe below eye extending anteriorly onto maxilla and posteriorly to vertical margin of preopercle and underlain below pupil by abutting white stripe; throat, cheek and breast yellow. Thin dark basal stripe in second dorsal fin followed by pupil-diameter wide yellow stripe which continues anteriorly into first dorsal fin, membrane of second spine of first dorsal fin heavily invested with black melanophores, very faint amorphous yellow stripe in anal fin, pelvic fin membranes yellow. Male (26.6 mm SL) from Tobi Island (Fig. 21 C) with yellow background (especially on lower half of body above anal fin) with much more dark pigment above this extending anteriorly to eye, amorphous dark blotches anterior and posteroventral to eye, black and yellow stripes in dorsal fins well developed with most of membranes dorsal to yellow stripe in first dorsal fin heavily invested with small black melanophores, and some basal yellow streaks in caudal fin. Juvenile (10.3 mm SL, Fig. 21 D) with translucent dorsum margined dorsally by light tan, posteroventral part of head dark red (possibly due to gills), snout and lips yellow-brown, large amorphous black chromatophores on dorsal braincase, and over opercular region, abdomen and vertebral column (where densely scattered), lower part of vertebral column and upper abdomen light reddish yellow which extends down haemal spines, upper half of head and snout yellowish, iris black mottled with gold, and narrow gold ring around pupil. Caudal blotch intensely black, light bar across peduncle anterior to blotch broad, no trace of lateral light stripe. Specimens from main Palauan islands similar (Fig. 22). Overall background redder than described above in 18.7 mm SL female (Fig. 22 A), with less well demarcated light lateral stripe, smaller caudal blotch, white bar anterior to caudal spot poorly developed, stripe across top of pupil blue, two blue spots at anterior and posterior ventral margins of pupil, and dark internal stripe over abdominal cavity and along body less obvious. A 22.5 mm SL male (Fig. 22 B) similar to 26.6 mm SL male (Fig. 21 C), but red and white stripes below eye extend from jaws to vertical limb of preopercle and second dorsal spine of first dorsal fin much longer. Red borders to light lateral stripe very clear in 23.2 mm SL female (Fig. 22 C) and continue anteriorly bordering blue stripe across pupil; red stripe on cheek continues diffusely below pectoral fin base and on to abdomen, ending above anal fin origin.
Preserved: Similar to above, but all colour faded (Fig. 23). Background pale straw, scale pockets on nape and dorsum outlined with very small round black melanophores and larger, lighter, amorphous brown chromatophores which may also extend into centres of scale pockets, most concentrated along dorsum adjacent to dorsal fin bases; broad, posteriorly tapering wedge of internal brown chromatophores over abdomen ending at caudal spot; upper half of pectoral fin base, upper opercle, and posterodorsal portion of cheek with scattered, larger, amorphous, light brown and smaller, darker, rounded chromatophores; snout in front of eye with very dark but ill-defined blotch; dorsomedial surface of upper lip heavily invested with dark, irregular chromatophores; lower one-third of head (including chin) and body with virtually no pigment cells (Fig. 23 A). Dorsal surface of snout (Fig. 23 B) with poorly defined central stripe, wider anteriorly where made up of amorphous brown chromatophores mixed with smaller, rounder and darker pigment cells and a few slightly larger and darker cells, more or less constricted to central ridge between eyes where consists almost entirely of small rounded dark cells before fading out in predorsal midline. Caudal spot (Fig. 23 C) of large rounded, internal light and dark brown chromatophores with small dark pigment cells on surface. Small juvenile (8.4 mm SL) with rounded black melanophores confined to dorsal surface of braincase with two small dark blotches adjacent to nares (Fig. 23 D), a few dark chromatophores in lining of anterodorsal part of abdominal cavity, caudal spot well developed with internal and external large, irregular, brown chromatophores, smaller ones between bases of procurrent caudal fin rays, remainder of head and body without pigment cells. (Fig. 23 E)
Etymology. The name burridgeae is a tribute to Mary Elizabeth Burridge in recognition of her extensive work in the revisions of the gobiid genus Priolepis, her ongoing work on barcoding Trimma spp., her field work collecting fishes in the Philippines and Vietnam, and her extensive contributions to the maintenance of the fish and frozen tissue collections at the Royal Ontario Museum.
Distribution. Based only on material examined in this study, the range of T. burridgeae is virtually confined to outer reefs with vertical walls throughout the Palauan islands (Fig. 11). Although collected between 4–50 m, this species is most abundant in caves and under overhangs between 20– 30 m.
Comparisons. See under Trimma tevegae for differences between various similar-looking species.
Discussion. The length of the second spine of the first dorsal fin is sexually dimorphic. Based on specimens from both the Main and the Southwest Islands, the spine in adults (<17 mm SL) is significantly shorter in females than in males (ANCOVA, p-value for sex = 0.00614). The adpressed tip of the spine reaches to between the base of the third ray of the second dorsal fin to the second scale behind the last ray (mean between bases of sixth and seventh rays, n = 15) vs. to between the base of the third ray of the second dorsal fin to the eighth scale behind the last ray (mean to second scale behind last ray, n = 14) in males. The third dorsal spine is also a little elongated, reaching on average to between the bases of the spine and first ray of the second dorsal fin in females (n = 15) and to between the bases of the first and second rays in males (n = 13). However, this apparent difference was not significant between males and females (ANCOVA, p-value for sex = 0.0605).
Almost half (3 of 7) the non-type specimens from Uchelbeluu Reef collected in 90–90.4 m (ROM 70729 and 70730) have a branched fifth pelvic fin ray. Genetic material of specimens from this depth and locality would be the simplest way to test for con-specificity with the rest of the material, as no other differences were apparent.
description: Published as part of Winterbottom, Richard, 2016, Trimma tevegae and T. caudomaculatum revisited and redescribed (Acanthopterygii, Gobiidae), with descriptions of three new similar species from the western Pacific, pp. 1-53 in Zootaxa 4144 (1) on pages 28-36, DOI: 10.11646/zootaxa.4144.1.1, http://zenodo.org/record/257666