Trimma tevegae Cohen & Davis 1969
Creators: name: Winterbottom, Richard
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Gobiidae
Trimma
Trimma tevegae

description: Trimma tevegae Cohen & Davis, 1969
Tevegae Pygmygoby
Figs. 1–12, 31.
Trimma tevegae Cohen & Davis, 1969:321 (Rabaul, New Britain); Allen & Erdmann, 2012:948, Raja Ampat (Red Sea to western Pacific—many of these records may represent other species); Winterbottom et al. 2014:88 (Group 6 only)
Material examined. Holotype. USNM 203436, 19.2 mm SL female, Papua New Guinea (PNG), New Britain, Rabaul, Simpson Bay, Dawapia Rocks, 40–50' (= 12.2–15.2 m), 5 Mar., 1965, D. M. Cohen & W. P. Davis.
Paratypes. USNM 203437, 9(12.5–20.0), collected with the holotype.
Additional material from the type locality. All specimens collected with clove oil from the south side of Dawapia Rocks, Rabaul, New Britain in November, 2011 by R. Winterbottom & W. Holleman: ROM 86598, (18.2), 4°14.134'S, 152°10.038'E, 19.5 m, RW11-04AR 2, 20 Nov. ROM 88119, (17.9), 4°14.164'S, 152°10.023'E, 19.2 m, RW11-02CR 1, 19 Nov. ROM 88124, 3(16.7–17.2), 4°14.155'S, 152°10.034'E, 19.5 m, RW11-03CR 1, 20 Nov. ROM 88143, (20.3), 4°14.134'S, 152°10.038'E, 17.7 m, RW11-04CR 2, 20 Nov. ROM 88153, (20.3), 4°14.141'S, 152°10.030'E, 16.2 m, RW11-06DR 2, 21 Nov. ROM 92091, 4°14.127'S, 152°10.015'E, 13.4 m, RW11-07CR 1, 22 Nov. ROM 92112, (18.2), 4°14.167'S, 152°10.029'E, 18.3 m, RW11-08HR 1, 22 Nov. ROM 92121, (15.4), 4°14.167'S, 152°10.029'E, 20 m, RW11-08BW 2, 22 Nov. ROM 92139, 3(16.2–19.2), 4°14.160'S, 152°09.950'E, 21.9 m, RW11-10ER 1, 23 Nov. ROM 92152, 2(17.2–17.9), 4°14.160'S, 152°09.950'E, 18.2 m, RW11-10BW 2, 23 Nov. ROM 92172, 2(15.3–17.3), 4°14.167'S, 152°10.029'E, 30.5 M, RW11-12AR 2, 24 Nov. ROM 92177, (18.2), 4°14.167'S, 152°10.029'E, 32.4 m, RW11-12AW 2, 24 Nov. ROM 92182, 8(12.9–20.3), 4°14.144'S, 152°10.010'E, 26.8 m, RW11-13BR 2, 25 Nov. ROM 92246, 3(16.0–17.5, 4°14.144'S, 152°10.010'E, 19.5 m, RW11-13CR 2, 25 Nov. ROM 92253, (14.2), 4°14.144'S, 152°10.010'E, 18.9 m, RW11-13JR 2, 25 Nov. ROM 92265, (17.3), 4°14.185'S, 152°09.980'E, depth not recorded, RW11-14BW 2, 25 Nov. ROM 92268, (14.5), 4°14.185'S, 152°09.980'E, depth not recorded, RW11-14IR 2, 25 Nov. ROM 92271, 3(19.0–20.1), 4°14.185'S, 152°09.980'E, 17.1 m, RW11-14DR 1, 25 Nov. ROM 92277, 3(13.1–20.0), 4°14.185'S, 152°09.980'E, 21.3 m, RW11-14BR 1, 25 Nov. ROM 92285, (18.6), 4°14.185'S, 152°09.980'E, 17.8 m, RW11-15CW 2, 26 Nov. ROM 92290, 4(18.1–19.3), 4°14.185'S, 152°09.980'E, 15.2 m, RW11-15JR 1, 26 Nov. ROM 92304, (17.0), 4°14.185'S, 152°09.980'E, 16.5 m, RW11-15IR 1, 26 Nov. ROM 92313, (19.1), 4°14.185'S, 152°09.980'E, 19.8 m, RW11- 15FR 1, 26 Nov. ROM 92321, (21.0), 4°14.185'S, 152°09.980'E, 17.4 m, RW11-15HR 1, 26 Nov. ROM 1914CS (was ROM 92259), 3(15.8–17.5), 4°14.185'S, 152°09.980'E, 23.8 m, RW11-14AR 1, 25 Nov. Tissues: T13142, collected with ROM 88119. T13148, collected with ROM 88124. T13157, collected with ROM 88143. T13162, collected with ROM 88153. T13168, collected with ROM 92091. T13172, collected with ROM 92112. T13180 – 81, collected with ROM 92139. T13183, collected with ROM 92152. T13192, collected with ROM 92182. T13139, 4°14.164'S, 152°10.023'E, 27.7m, RW11-02AR 1, 19 Nov. T13140, 4°14.164'S, 152°10.023'E, 21.4 m, RW11-02JW 1, 19 Nov. T13141, 4°14.164'S, 152°10.023'E, 22.7 m, RW11-02AW 1, 19 Nov. T13169, 4°14.147'S, 152°10.029'E, 28.7 m, RW11-08ER 1, 22 Nov.
Material from other localities. Indonesia: Halmahera: ROM 93641, 3 (17.6–24.90), Proco, 00°24.344'S, 127°43.341'E, 14 m, 2 May, 2012, M.V. Erdmann (plus tissue specimen, ROM T12743). Moluccas: ROM 98807, 6 (17.5–18.7), Banda harbour, 04°30.794'S, 129°53.589'E, 48 m, 7 Oct., 2014, M.V. Erdmann (plus two tissue specimens, MB0615201 and MB0615202). Raja Ampat: ROM 85131, 20 (7.8–19.60), Jef Tsiep Id, west side, channel between it and small island to the west, steep coral rock wall in sandy slope with patch reef, 00°23'05.7''S, 130°16'37.1''E, 19.8–22.9 m, clove oil, 28 Jan., 2010, RW10–20, R. Winterbottom et al. ROM 85224, 3 (16.7– 20.6), Wofoh Id, west coast near south end, vertical wall and large cave, 00°15'21.9''S, 130°17'32.0''E, 12–16 m, clove oil, 29 Jan., 2010, L. Katz et al. ROM 85311, 7 (10.5–16.5), S of Misool Id off Waaf Id, wall and cave, 02°08'56.4''S, 130°13'17.0''E, 20 m, clove oil, 1 Feb., 2010, M. V. Erdmann (plus tissue specimen, ROM T07760). ROM 85320, 23 (13.9–22.0), Kepotsol Id (SE of Misool Id), 02°09'32.1"S, 130°17'34.0"E, 18.3–21.3 m, 1 Feb, 2010, Winterbottom et al. (plus tissue specimen, ROM T07762). ROM 85337, 4 (13.2–14.6), Kepotsol Island, north side, slope with cracks, 02°09'32.1''S, 130°17'34.0''E, 3 m, clove oil, 1 Feb., 2010, M. V. Erdmann. ROM 85379, 2 (17.4−17.9), SE islands off Misool, south side of Balbulol Island, deep undercut in vertical wall with sand/silt/ rubble floor, 02°01'29.5''S, 130°41'34.9''E, 13.7–18.3 m, rotenone, 2 Feb., 2010, R. Winterbottom et al. ROM 85388, 3 (16.5–22.1), SE islands off Misool, south side of Balbulol Id, cave in reef slope, 02°01'29.5''S, 130°41'34.9''E, 15 m, rotenone, 2 Feb., 2010, M. V. Erdmann. ROM 87437, 4(21.9–25.0), Mesempta, SE Misool Id, deep inlet in island, vertical wall with cracks, silt & rubble bottom, 01°58'43.2''S, 130°27'56.9''E, 18.3–24.4 m, rotenone, 3 Feb., 2010, Winterbottom et al. ROM 93642, 2 (21.6–25.10), Indonesia, Raja Ampat, Batu Kapal, 00°21.948'S, 130°27.937'E, 20 m, 29 Mar., 2012, M. V. Erdmann (plus 3 tissue specimens, ROM T12740–12472). Malaysia: Sabah: ROM 56633, (20.0), Pulau Sipidan, 8 m, 8 Sept., 1980, M. Swan. Philippines: Cebu: ROM 49223, 2 (8.7–18.1), off Hudson Beach about 2 km S of Tambuli Beach Resort, vertical wall of drop-off, 10°15'N, 124°00'E, 12–20 m, rotenone, 7 Aug., 1985, R. Winterbottom & E.O. Murdy. Oriental Negros: ROM 53092, 6 (12.1−26.6), mouth of Bais Bay, 09°36'54''N, 123°11'06''E, 24.4–36.6 m, rotenone, 15 May, 1987, R. Winterbottom et al. Palawan: ROM 88026, (18.0), Apuilt Id, 10°57.677'N, 119°36.990'E, 30 m, 24 May, 2011, M. V. Erdmann (plus three tissue specimens, ROM T12721–T12723). Siquijor: ROM 53090, 2 (15.8–20.3), Tonga Point, west side about 1 km from tip of point, 09°12'16''N, 123°27'16''E, 4.6–12.2 m, rotenone, 9 May, 1987, D. Johnson et al. ROM 53096, (21.9), Tonga Point, 09°12'17''N, 123°27'14''E, 9.1–21.3 m, rotenone, 22 May, 1987, R. Winterbottom et al. Solomon Islands: Guadalcanal Island: ROM 46130, 13 (8.2–20.5), 11.7 km NW of Honiara, wreck of ' Bonegi 1', gap in west side of wreck, 09°23.440'S, 159°52.817'E, 18–22 m, rotenone, 14 Mar., 19834, R. Winterbottom et al. ROM 46132, 9(11.6–18.3), as for ROM 46130, east side and hold of wreck, 09°23.440'S, 159°52.817'E, 18–22 m, rotenone, 15 Mar., 1983, R. Winterbottom et al. ROM 0839 CS, (16.3), wreck of Japanese ship (‘Kyusyu Maru’) about 12 km NW of Honiara, inside of wreck on vertical face of superstructure, soft and hard corals, sponges and hydroids, 09°21.159'’S, 159°50.609'E, 20–22 m, PN83- 01, 24 Apr., 1983, P. Nichols & D. Evans.
Diagnosis. A species of Trimma with a bony interorbital 70–95% pupil diameter, a fully scaled nape with the anterior 2–4 rows cycloid, a second dorsal spine that does not reach beyond the base of the third dorsal fin ray, and is usually much shorter than this, papillae in longitudinal row immediately below eye single or with two papillae in a vertical row but not in vertical rows of 3–5 papillae each, usually unbranched pectoral-fin rays, an unbranched fifth pelvic-fin ray that is about 50% the length of the fourth ray, and a large dark blotch on the posterior caudal peduncle. Fresh, mature specimens> 15 mm SL may have a white to bluish-white stripe along the midline of the body reaching across the dorsal margin of the pupil, no light blue stripe in the dorsal midline or beneath the eye across the upper cheek. Preserved specimens have a fairly uniform light brown dorsal surface of the snout formed of rounded or anastomosing chromatophores with scattered, larger and much darker spots, the cheek below the eye has little pigment but with a thin line of brown chromatophores touching the ventral edge of the orbit, and usually a brown spot on the chin just behind the symphysis of the lower jaw.
Description. The redescription is based on up to 50 specimens, 12.9–21.0 mm SL (mean 17.7) from 25 lots collected at the type locality (Dawapia Rocks, Simpson Harbour, Rabaul, New Britain, PNG) in 2011. An additional 14 specimens of this species were collected for analysis of the COI gene (see Genetics). Dorsal fin VI + I 8, second spine slightly to moderately elongated, reaching to between interspace between dorsal fins and base of third ray of second dorsal fin (Table 1), all fin rays branched except for posterior element of last ray, which reaches posteriorly 20–41% (mean 27.8%, n = 33) distance between its base and first exposed dorsal procurrent caudal fin ray; anal fin I 8 (once 7), first ray usually unbranched (branched in 11 of 50 specimens), which reaches posteriorly 22–46% (mean 29.0%, n = 33) distance between its base and first exposed ventral procurrent caudal fin ray; pectoral fin 12–14 (mean 13.0, n = 50, 12 once, 14 in three), rays unbranched (once 1 ray branched in middle of fin, one side only); pelvic fin I 5, fifth ray unbranched (branched in 1 of 50 specimens) and 46–60% (mean 52.0, n = 40) length of fourth ray, which reaches posteriorly to between urogenital papilla and base of fourth anal ray, pelvic rays 1–4 with a single sequential branch point; basal membrane 4–8% (mean 5.4, n = 21) length of fifth ray; no fraenum. Lateral scales 23 (n = 37); anterior transverse scales 9–10 (mean 9.4, n = 32); posterior transverse scales 8–9 (mean 8.1, n = 33); predorsal scales 9–11 (mean 9.9, n = 36), first 2–4 rows (Fig. 1) and often posterior-most scales of predorsal midline cycloid (all cycloid in 12.9 mm SL specimen), usually cycloid scales around posterodorsal rim of orbit, scales reaching anteriorly to above anterior to middle of pupil; cheek with 1–3 rows of cycloid scales, uppermost row (if present, 9 of 17) of 1–2 scales, middle row of 7 scales (once 8, n = 17, see Fig. 2), lowest row (15 of 17) of 1–2 scales; opercle with 3–4 horizontal rows of 6–9 mostly cycloid scales (Fig. 2; note very small supernumerary dorsal opercular scale), a few larger, more central, scales may be ctenoid; 3 vertical rows of cycloid scales on pectoral fin base with 1–3 in anteriormost row and 3–4 in next two rows; 7–8 (mean 7.4, n = 17) cycloid scales in midline anterior to pelvic fin base; area between pelvic spine and ventral margin of pectoral fin base, midline of belly and sometimes anteriormost row of body scales beneath axil of pectoral fin base with cycloid scales. Upper jaw with outer row of enlarged, curved, closely spaced teeth, decreasing in size posteriorly, reaching almost to posteroventral tip of premaxilla, 1–2 irregular inner rows of small conical teeth grading posteriorly to single row extending almost to posteroventral tip of premaxilla, innermost row slightly enlarged and pointing posteriorly, ending at bend of premaxilla. Lower jaw with outer row of about 5–6 enlarged, curved, spaced canines ending at bend of dentary, followed by 1–2 rows of small conical teeth which grade posteriorly to single row just posterior to bend and end near dorsal tip of coronoid process of dentary, some of these teeth enlarged to twice size of others. (Description of teeth based on cleared and stained material). Tongue truncate with rounded edges. Gill opening extending anteroventrally to below mid-pupil; gill rakers 2–4 + 13–15 = 16–20 (mean 3.0 + 14.0 = 17.0, n = 42; 2 and 4 upper rakers once each, 13 and 15 lower rakers in 7 specimens each). Anterior nares in 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 3–4 times its diameter, nasal sac raised and on anterior one-third of snout. Bony interorbital width 70–95% (mean 82.4, n = 16) pupil diameter; shallowly concave with median fleshy ridge forming broadly rounded W in cross section; epaxialis extending anteriorly to point above middle of pupil. Caudal peduncle depth as percentage caudal peduncle length 33.3–43.3 (mean 37.5, n = 31); head length as percentage SL 28.9–35.0 (mean 31.5, n = 49); as percentage head length: horizontal eye diameter 32.5–37.2 (mean 35.3, n = 49); snout length 20.3–26.9 (mean 23.0, n = 49), cheek depth 8.9–17.2 (mean 12.1, n = 39). Cephalic sensory papillae as in Figs. 3 and 4 (latter includes named papillae lines), number of papillae in each row given in Table 2. Abdominal/ caudal vertebral transition Type A, with haemal arches of first two caudal vertebrae expanded (data from ROM 1914CS and ROM 0839CS).
Colour pattern. Live, based on underwater photographs from Banda, Cendrawasih Bay and Halmahera, Indonesia. Banda specimen (dorsolateral view, Fig. 5 A): dorsum with dark olive-green scale margins and partially translucent dark salmon scale centres, followed by light stripe about one scale in height from upper eye and gently curving ventrally to end at mid-peduncle where it forms posterodorsal to anteroventral irregular bar across entire width of peduncle just anterior to position of ural complex, with scale margins iridescent whitish blue and scale centres amethyst; an eye-diameter black blotch over ural complex and bases of caudal-fin rays grading to dark red along posterior margin; ventrum dark red mixed with dark olive green above anal fin with narrow off-white stripe from peduncle to below pectoral-fin base and continuing anteriorly across cheek just below eye and onto chin. Head dark red above this, including most of upper jaw and medial half of lower jaw and thin line margining ventral edge of orbit. Snout also dark red mixed with dark olive green and a few light spots (may be due to reflection from camera strobe). Eye brownish, darker above with narrow gold ring around pupil, bluish-white body stripe continuing anteriorly across top of iris and touching dorsal rim of pupil, area just above this stripe red, three diffuse small light spots ventrally at 4, 6 and 8 o’clock positions. Base of pectoral fin just anterior to bases of fin rays with diffuse golden bar. Diffuse yellowish-red saddles at anterior and posterior ends of second dorsal fin and another smaller saddle just anterior to white bar on peduncle. Fin elements of dorsal fins red, other fins translucent but with vague reddish stripes on lobes of caudal fin. Specimen from Halmahera (Fig. 5 B) essentially similar, but dorsum lighter with white scale margins on anterior half, light lateral stripe less obvious, ventrum orange-yellow, and all visible fin elements brick-red. Cendrawasih Bay specimen (Fig. 5 C) a cross between these two, with light lateral stripe very diffuse, abdomen and posterorventral body orange with dense pattern of dark subdermal chromatophores, and white bar on peduncle broader.
Freshly collected. Based primarily on four images (Fig. 6, out of 24 available images) from Dawapia Rocks, Rabaul, New Britain, two of which, A and D, represent tissue specimens. Specimen in Fig. 6 A (16.0 mm SL female) with irregularly dark dorsum followed ventrally by ill-defined lighter stripe from posterodorsal eye to peduncle, where it expands dorsally and ventrally to form light bar just ahead of large black blotch covering remaining part of peduncle and anterior ends of caudal-fin rays, a dark reddish-black ventrum extending anteriorly in almost straight line from base of last anal ray to below pectoral-fin base, continuing anteriorly just below ventral margin of orbit to tip of lower jaw, area below this pale, with little pigment. Tip of lower jaw, most of upper jaw, area above this, and margin of eye red with scattered large melanophores, red continues posteriorly in thin line below eye, cheek and opercle above this line red with scattered large melanophores except for vertical limb of preopercle, where melanophores virtually absent. Cheek below thin red line with scattered erythrophores and small brown melanophores. A few dark melanophores along sides of lower jaw just posterior to red tip. Snout and interorbital region brown with scattered large melanophores, iris mottled with black, brown and gold pigment cells with some red which is concentrated as vague stripe above diffuse black stripe above dorsal margin of pupil which is rimmed with thin yellow halo. Anterior part of nape brick-red, as are scale margins of dorsalmost 2–3 rows of body scales, scale pockets increasingly invested with brown and black pigment posteriorly with small lighter patch below end of second dorsal fin. Lighter stripe from posterodorsal eye to peduncle mainly due to fewer pigment cells and scale margins not as well outlined with red, dark pigment in scale pockets less intense and more or less confined to posterior margins of pockets; light bar over peduncle 1–2 scales wide, with numerous large dark pigment cells on ventral half. Caudal blotch covers full depth of peduncle, made up of brick-red pigment heavily invested with large dark brown and black pigment cells, anterior and posterior margins with only red chromatophores. Red ventral stripe of red to orange suffusion with many irregular dark brown chromatophores and scattered, better defined, larger and rounded melanophores. Pectoral-fin base with brick red suffusion with numerous large dark pigment cells, with slight concentration of these cells on dorsal margin to form diffuse dark spot, fin rays reddish, membranes apparently hyaline. Pelvic fin elements hyaline with scattered yellow-brown pigment cells. First dorsal fin with reddish spines and diffuse, one-third pupil diameter wide stripe of reddish pigment cells about half-pupil diameter in height above base followed by a clear area with distal one-third of fin with scattered dark pigment cells; second dorsal fin with orange-red stripe, widening somewhat posteriorly above half pupil diameter basal stripe which is clear anteriorly but lightly invested with dark pigment cells posterior to base of second dorsal fin ray, distal half of fin hyaline. Anal fin with clear basal half except for few scattered dark pigment cells in posterior half, distal half with yellow suffusion invested with numerous darker pigment cells. Caudal fin with numerous scattered dark pigment cells dorsally, ventrally and posteriorly, with three diffuse red lines along branched caudal rays, anterior middle part of fin clear, bases of fin rays red (part of caudal blotch). A 16.8 mm SL male (Fig. 6 B) more densely pigmented, light lateral stripe less evident and almost obliterated ventrally, as is white bar on peduncle, ventrum more yellow over abdomen, underside of lower jaw and most of lower half of cheek with numerous erythrocytes, iris with diffuse dark bar crossing it just above pupil, middle of pelvic fin yellow, basal dark stripe in first dorsal followed by red stripe, dark basal stripe of second dorsal complete followed by orange-yellow stripe in membranes and red fin elements, and distal two-thirds of anal fin yellow. In a 19.2 mm SL female (Fig. 6 C), dorsum dark with lighter diffuse saddles at mid-nape, interspace between dorsal fins and below last ray of second dorsal fin, white stripe well developed (up to 1.5 scales wide), ventral half of white peduncular bar well developed but dorsal counterpart less so, lower cheek and posteroventral part of lower jaw moderately pigmented. Both stripes in first dorsal fin virtually absent, basal stripe in second dorsal virtually absent, stripe above it less well developed, as is yellow stripe in anal fin, and no red stripes in caudal fin. The 19.8 mm SL male (Fig. 6 D) much like preceding female, dark bar across top of pupil better defined, ending in anterior bluish spot, colouration of dorsal fins as for 16.8 mm SL male, upper third of pectoral base with diffuse light band.
Preserved. (Note: specimens which have lost scales tend to have a somewhat distorted colour pattern). Body pale straw-yellow, dorsum heavily pigmented with diffusely defined dark brown chromatophores mixed with smaller, better defined, rounded and darker chromatophores, former type absent below second spine of first dorsal fin, spine of second dorsal, and bases of last two dorsal fin rays to form slightly lighter saddles (Fig. 7). Diffuse chromatophores not extending ventrally for more than 1–2 scales, defined chromatophores decreasing in number (but still present) as far as midlateral septum, forming vague lighter stripe along body. Below midlateral septum, concentration of chromatophores mix with less defined, larger brown pigment cells to form darker ventral stripe (but not as dark as dorsum), number of chromatophores decreasing on ventral portion of body, and virtually absent about two scales lateral to midline. Nape heavily pigmented along scale margins (see Fig. 3) with dark rounded chromatophores, opercle well pigmented with similar chromatophores and with larger, more amorphous, lighter brown chromatophores, cheek immediately below eye and anterior to vertical limb of preopercle with scattered brown chromatophores with only a few pigment cells below line d of sensory papillae, lips heavily pigmented with small, dark, rounded chromatophores except distally, where clear. Top and sides of snout densely pigmented with small, dark, rounded chromatophores mixed with slightly larger, amorphous, lighter brown chromatophores, and a sprinkling of much larger, darker, rounded chromatophores (some indicated by blue arrows in Fig. 8). Ventral region just behind lower jaw symphysis usually with a diffuse dark blotch made up of rounded dark chromatophores (Fig. 9). Caudal peduncle (Fig. 10) with large, amorphous, brown chromatophores on ventral half becoming smaller, more rounded and fewer dorsally, light peduncular bar vaguely recognizable on dorsal (but not ventral) half as areas lacking pigmentation, dark caudal spot encompassing last two lateral scales plus an equal area over caudal fin ray bases, formed by mix of amorphous large brown pigment cells, smaller, more rounded darker brown cells and a few larger, even darker rounded chromatophores; caudal fin membranes mostly hyaline except for distal band of irregularly outlined, brown chromatophores. Posterior base of first dorsal with few large brown chromatophores, base of second dorsal with well-defined basal stripe of brown chromatophores which continues to distal margins of last two fin rays. Pigment virtually absent from anal, pelvic and pectoral fins, base of latter heavily invested with well-defined rounded dark brown chromatophores.
Etymology. Named after the American research vessel “Te Vega”, a converted luxury yacht, operated at the time the type specimens were collected (1965) by Stanford University's Hopkins Marine Station.
Distribution. Based only on material examined in this study, the range of T. tevegae covers the area between north-east Borneo and the northern Philippines southward to the Solomon Islands (Fig. 11). The species appears to be absent from Australian, Palauan and Japanese waters, but is probably more widely distributed in Indonesia than currently documented. The report on the presence of this species from Jeddah, Red Sea (Winterbottom, 1995:98) is erroneous, and was based on misidentified specimens of T. fishelsoni Goren, 1985 (specimens from WAM, not ANSP, as stated).
Comparisons. Among the described species of Trimma possessing a broad bony interorbital, all five species dealt with here, as well as T. xanthochrum, T. yoshinoi, T. griffithsi Winterbottom, 1984 and T. nasa Winterbottom, 2005b have a dark spot on the hypural region of the caudal peduncle. Trimma griffithsi and T. nasa can be distinguished from the species described in this paper in having a branched fifth pelvic ray, no scales on the cheek, and only cycloid scales on the nape (vs. fifth ray unbranched, cheeks scaled, and ctenoid scales on at least the posterior two-thirds of the nape). The caudal spot in T. griffithsi is much smaller than in any of the other species, and is confined to the lower half of the peduncle. Trimma nasa has a very light colouration with much less pigment on the body compared to the species treated here, except for a dark ‘shadow’ created along the side of the body by pigment on the peritoneum. The Trimma described in this paper are also more heavily pigmented along the dorsal surface than T. nasa. Trimma xanthochrum and T. yoshinoi differ from the species described here in having the row of papillae under the eye consisting of short vertical rows of 2–3 papillae each in row 2, 3 and 4 (vs. single papilla at each position except for row 2 in a few specimens of T. burridgeae and T. hollemani, where 2 papillae may be present), the mid-snout and posterior interorbital papillae of row p (the third and fifth papillae in the row counting from the anteriormost) consisting of short transverse rows of 2–4 papillae (vs. usually a single papilla), branched rays in the mid-region of the pectoral fin (vs. rays usually unbranched), and usually having a fifth pelvic ray that is branched once (vs. unbranched).
Trimma tevegae can be distinguished from the other four species treated here only by a combination of characters (Table 3). It has a short second dorsal spine (maximum length when adpressed only reaching to the base of the third ray of the second dorsal fin vs. to fifth ray or beyond in T. burridgeae and T. caudomaculatum), in usually having 13 pectoral fin rays, 17 total gill rakers and no blue stripe (dark in preservative) along the midline of the snout to the origin of the first dorsal fin (vs. usually 14, 18 or more, and snout stripe present respectively in T. burridgeae, T. caudomaculatum and T. hollemani). In these three characters, it resembles T. corerefum. However, it differs from that species in the preserved colour on the top of the snout by the presence of several large, dark, rounded chromatophores (see arrows in Fig, 8) in addition to the smaller rounded chromatophores mixed with amorphous large light brown chromatophores that are also present in T. corerefum. This latter species is morphologically the most distinctive of the group. It differs from all the other species in a shorter fifth pelvic fin ray (45% or less of length of 4th pelvic ray vs. 46% or more), usually a single row of cheek scales with a total of 7– 8 scales (vs. two or more rows totalling more than 8 scales), in nearly always having fewer papillae in rows d ʹ, ea, ep, r, f and ot (a maximum of 5, 10, 13, 2, 2 and 11 respectively vs. a minimum of 6, 11, 12, 3, 3 and 11), in the posteroventral body pigment above and behind the anal fin in preserved material consisting almost entirely of widely-spaced, amorphous, light brown chromatophores with only a very few tiny round, black melanophores (vs. this area much more densely pigmented, with a variety of different and darker chromatophores), and in the four discrete clusters of small round melanophores around the eye (vs. such discrete clusters absent). Trimma burridgeae, T. caudomaculatum and T. hollemani all have a blue stripe (dark in preservative) extending from the midline of the tip of the snout to at least the origin of the first dorsal fin (and sometimes even further posteriorly). The posterior extent of the dark stripe in preserved material becomes faint or absent posterior to the orbit. In the first two species, the mean position of the abducted second dorsal spine reaches posteriorly just beyond the end of the second dorsal fin, whereas in T. hollemani it reaches to the base of the third dorsal fin ray. However, the usefulness of this character in separating these species is offset by the large variance in spine length in individual specimens. In T. hollemani, the dark stripe on the snout is often made up of amorphous, brown chromatophores, but the stippled stripe of the other two species is also present, including in all specimens from the Philippines. To make matters more difficult, the latter also have the longest second dorsal spines among the specimens examined (Table 1). It is unfortunate that no specimens from the Philippines were available for genetic analysis. Trimma caudomaculatum can be separated from the other two species on the basis of colouration. Live specimens have blue blotches anterior to the eye, on the iris at the five o’clock position, and on the opercle level with the ventral part of the pupil, and a blue stripe under the eye that extends posteriorly at least as far as the bend of the preopercle, and often continues to the posterior margin of the subopercle (see Fig. 16). These are retained (except for the one on the iris) as dark blotches or a stripe in preserved material (see Fig. 18). These markings are absent in T. burridgeae and T. hollemani, although live specimens of the latter species may have a pale bluish-white stripe below the eye (which is not apparent in preserved material). Trimma burridgeae has a mean of 4 free neuromasts in row r (vs. a mean of 5 in T. hollemani), and differs further from all other species in this group in having a broad diffuse internal dark stripe over the abdominal cavity which narrows and continues posteriorly on and just below the vertebral column in freshly collected and in preserved specimens. Finally, T. burridgeae has a mean of 19.5 total gill rakers (vs. 18 for the other two species), and T. caudomaculatum has a mean of 11 predorsal scales (vs. 10 for T. hollemani —see Table 3). The difficulties in identifying these species (along with the members of the T. xanthochrum group) are exacerbated by the fact that several of them may co-occur syntopically, and may even form mixed schools.
Discussion. The length of the second spine of the first dorsal fin of T. tevegae was postulated to be sexually dimorphic by Cohen & Davis (1969:321), with females having a shorter spine. In an attempt to quantitatively test this hypothesis, spines that did not reach the base of the first spine of the second dorsal fin were scored as 0, those reaching the spine base were given a value of 1, with the number increasing with fin ray base number after that (to a maximum of 3). Females scored between 0 and 2, with a mean of 0.6 (n = 25); males between 0 and 3, with a mean of 1.5 (n = 12). Thus, the adpressed second dorsal spine of females reaches, on average, to just anterior to the base of the dorsal spine of the second dorsal fin whereas that of males reaches to between the bases of the spine and first ray of that fin. However, the length of the spine is not a good indicator of sex because there is a significant interaction between SL and sex whereby small individual females have longer spines but large individual males have longer spines (ANCOVA, p-value for SL*sex interaction = 0.00063, Fig. 12 A). This would tend to refute Cohen & Davis’ (op.cit.) suggestion of sexual dimorphism in this character (which was based on a single male and 9 females).
At the type locality of Dawapia Rocks, the average estimated underwater visibility during 19–26 November, 2011 was 9 metres (based on 12 dives). In two dives made outside of Simpson Bay at Little Pigeon Island, about 20 km to the south, the visibility was estimated at about 22 metres. No T. tevegae were seen or collected at the latter locality. In the Raja Ampat region of Indonesia, the average estimated visibility where this species was collected was 14.5 metres. It would seem that T. tevegae occurs most frequently in slightly turbid inshore waters, and is not generally present in the clear off-shore waters of oceanic reefs.
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 4-19, DOI: 10.11646/zootaxa.4144.1.1, http://zenodo.org/record/257666