Trimma

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 : 6-7

Key to the species of Trimma adults (> 16 mm SL)

1a Midline of predorsal with at least some scales, or, if scaleless, both interorbital and postorbital trenches well developed, with almost vertical sides................................................................................... 2

1b Midline of predorsal scaleless, interorbital and postorbital trenches either absent or with sloping sides................. 21

2a Interorbital and posterodorsal margin of orbit with a deep, almost vertically-sided trench ( Fig. 1 A)..................... 3

2b A trench or trough, when and if present, with sloping sides..................................................... 6

3a Pelvic fraenum present, side of interorbital trench with a row of vertically aligned scales, distal margin of first dorsal fin with black margin............................................................................... T. unisquame

3b Pelvic fraenum absent, side of trench scaleless, first dorsal without black margin................................... 4

4a Midline of predorsal scaleless or with only a few scales anteriorly with unscaled area anterior to origin of first dorsal fin........................................................................................ T. insularum sp. nov.

4b Midline of predorsal fully scaled......................................................................... 5

5a Second spine of first dorsal only marginally longer than third, cheek uniformly dusky or with two narrow vertical light bars, posterior caudal peduncle and fin not yellow........................................................ T. caesiura

5b Second dorsal spine of first dorsal fin usually elongated (to or beyond origin of second dorsal fin), cheek with dark red or brown blotches or bars but no light bars, posterior caudal peduncle and fin yellow........................... T. lantana

6a Fleshy interorbital ≥ pupil diameter ( Fig. 1 B)............................................................... 7

6b Fleshy interorbital <pupil diameter...................................................................... 12

7a Pectoral-fin rays unbranched............................................................................. 8

7b At least some pectoral-fin rays branched.................................................................. 11

8a Posterior region of peduncle the same colour or lighter than area anterior to it, not darker, caudal fin yellow in life.............................................................................................. T. kitrinum sp. nov.

8b Posterior region of peduncle either darker than area anterior to it, or with dark peduncular spot, caudal fin not yellow in life...................................................................................................... 9

9a Cheek scaleless, fifth pelvic-fin ray branched, midline of snout often with a dark stripe......................... T. nasa

9b At least posterodorsal region of cheek scaled, fifth pelvic-fin ray unbranched, midline of snout usually uniform in colour....................................................................................................... 10

10a Caudal peduncle with a dark blotch in region of hypurals, often a light longitudinal band on body just above mid-lateral septum............................................................................................. T. tevegae

10b Caudal half of body gradually becoming darker posteriorly, no light body band............................ T. flavatrum

11a Caudal-fin deeply forked, predorsal scales reaching half-way to orbit, fresh colouration translucent red (only the first haemal arch greatly expanded)........................................................................... T. hoesei

11b Caudal fin with upper rays longer than lower (wedge-shaped), predorsal scales reach orbit, fresh colouration translucent yel-

low often with darker yellow spots in the centers of the scales (first five haemal arches greatly expanded)......... T. taylori 12a Large, dark, rounded spot (1–1.5 X pupil diameter) present between pectoral-fin base and bases of first three dorsal spines.............................................................................................. T. nomurai

12b No large dark spot present in this position................................................................. 13

13a Light spots or lines on nape, pectoral-fin base and vertical limb of preopercle (yellow to red in life), scale pockets not strongly outlined by pigment................................................................................... 14

13b Cheek, pectoral-fin base and nape without well-defined light spots, bars or lines, scale pockets strongly outlined by pigment.................................................................................................... 17

14a Cheek below eye with a light vertical bar or two vertically aligned light spots, at least some central pectoral-fin rays branched................................................................................................... 15

14b Cheek below eye uniformly dusky, pectoral-fin rays unbranched............................................... 16

15a Cheek below posterior half of pupil with light, vertical bar, second spine of first dorsal fin not elongated (only reaching as far as base of second dorsal fin ray)................................................................. T. okinawae

15b Cheek below posterior half of pupil with two vertically aligned light spots, second spine of first dorsal fin elongated (reaching beyond base of second dorsal fin ray in males and many females)............................... T. readerae sp. nov.

16a Opercle with one to two scales, seven to eight rays in second dorsal fin, rounded red blotch on vertical limb of preopercle............................................................................................... T. annosum

16b No scales on opercle, usually nine dorsal rays, an ovoid yellow or orange blotch about half eye diameter in width on vertical limb of preopercle........................................................................... T. maiandros

17a Fifth pelvic-fin ray unbranched.......................................................................... 18

17b Fifth pelvic-fin ray branched............................................................................ 19

18a Scales present on dorsal margin of opercle, scale pockets outlined with dark chromatophores, plain yellowish to red-brown in life, iris without strongly contrasting colours in life...................................................... T. milta

18b Opercle scaleless, scale pockets poorly outlined, three light yellow stripes on body in life, iris with four yellow spots on a red/ magenta background.......................................................................... T. preclarum

19a Base of pectoral-fin uniform light brown............................................................ T. emeryi

19b Base of pectoral-fin with a dark, vertical bar.............................................................. 20

20a Eight anal-fin rays, fifth pelvic-fin ray branched once, pectoral-fin rays unbranched............... T. pentherum sp. nov.

20b Seven anal-fin rays, fifth pelvic-fin ray branched twice, about eight branched rays in pectoral fin....... T. meristum sp. nov.

21a Head and body with light spots, saddles, streaks or stripes (red or yellow in life)................................... 22

21b Head and body without light markings, more or less uniform in colouration...................................... 28

22a Head and nape with alternating, longitudinal light and dark stripes.............................................. 23

22b Head and nape with light spots, saddles, or short stripes...................................................... 24

23a Body plain or with small (<half pupil-diameter), diffuse, irregular light (red in life) spots, lower dark stripe on cheek separated from lower lip by clear space in midline............................................................ T. striatum

23b Body with large (up to pupil-diameter), discrete light spots, lower dark stripe on cheek continuous with pigment on lower lip........................................................................................ T. capostriatum

24a A large (half-pupil diameter) dark spot just above upper attachment of opercular membrane.................... T. fangi

24b No such dark spot................................................................................... 25

25a Cheek below posterior half of pupil with light, vertical bar, or with two vertically aligned light spots........ See couplet 15

25b Colour pattern not as above............................................................................. 26

26a Fifth pelvic-fin ray unbranched, light saddles across dorsum, no distinct round or ovoid light spots immediately below eye............................................................................................ T. maiandros

26b Fifth pelvic-fin ray branched, no light saddles across dorsum, distinct round or ovoid light spots on cheek immediately below eye............................................................................................... 27

27a Two vertically aligned dark-centred light spots on pectoral-fin base, origin of first dorsal spine in a light spot.................................................................................................. T. macrophthalmus

27b No dark-centred light spots on pectoral-fin base, origin of first dorsal spine in pigmented area............... T. necopinum

28a Fifth pelvic-fin ray nearly always unbranched.............................................................. 29

28b Fifth pelvic-fin ray branched........................................................................... 30

29a Four small dark saddles across dorsal midline of body, no black spot at anterodorsal margin of gill opening, pectoral-fin rays unbranched.................................................................................. T. anaima

29b No saddles across dorsum, small black spot just anterodorsal to upper attachment of gill opening, some pectoral-fin rays branched..................................................................................... T. stobbsi

30a Two short dark bars under eye, rim of orbit with thin band of melanophores, no dark spots above opercular opening, second dorsal spine usually elongated, deep interorbital trough............................................... T. benjamini

30b No dark bars under eye, no melanophore band around orbit, often a pair of horizontally aligned diffuse dark spots above dorsal attachment of opercular membrane, second dorsal fin spine usually not much longer than third, interorbital essentially flat........................................................................................ T. xanthum sp. nov.

Figures

FIGURE 1. Dorsal view of heads of A: Trimma caesiura, (26.3 mm SL male, ROM 64124, New Caledonia) to show fleshy interorbital width and interorbital and postorbital trenches; B: T. hoesei (21.7 mm SL female, ROM 83303, Palau) to show wide fleshy interorbital and fleshy median interorbital ridge. Photos by R. Winterbottom.