Nasal-bar pygmygoby, Nasal pygmygoby, Nasal pygmy goby,

Description
Dorsal spines (total): 7; Dorsal soft rays (total): 7-8 (usually: 8); Anal spine: 1; Anal soft rays: 7-9 (usually: 8); Pectoral fin rays: 13-15 (usually: 14); Pelvic fin rays: I, 5; Lateral ligne scales: 23; Transverse scales: 6; Predorsal scales: 5-7; Depth of body: 4.3-4.6 in SL. Second spine of first dorsal fin elongated, reaching posteriorly to caudal peduncle when adpressed, anterior half of last fin ray unbranched, all other rays branched, last ray often elongated, sometimes almost reaching procurrent-fin rays; Anal fin usually, all rays branched except anterior half of last ray, last ray often elongated, sometimes almost reaching procurrent-fin rays; Pelvic fin, first four rays with single sequential branch, fifth ray branched once dichotomously and about 60 % the length of fourth ray; Basal membrane complete but often damaged; No fraenum; Scales cycloid anterior to lines between pelvic- and ventral pectoral fin base, and dorsal pectoral fin base and base of fifth dorsal spine dorsally. Max. length: 2.3 cm SL. Depth range: 0 - 41 m, usually: 0 - 20 m.

Color
Body translucent, with sprinkling of red chromatophores on head and snout. Yellow chromatophores present on margin of eye bordering interorbital space, and white stripe from anterior portion of snout right through interorbital region to posterior margin of pupil. Large, eye-sized, dark red-brown spot on hypural region of peduncle, with rounded spot of melanophores in centre. Red coloration begins immediately behind eye and passes down side of body to mid peduncle region and appears to be entirely internal. Iridescent green suffusion present on peritoneum and along most of vertebral column (could be artefact of electronic flash photography). Sprinkling of red chromatophores present around bases of first two dorsal spines, with some red pigment present in fin rays of first dorsal and pectoral fins.

Etymology
Trimma: from Greek, trimma, -atos = something crushed.
nasa: derived from the old English word 'nasal', a bar descending from the front of many medieval helmets to protect the nose of the wearer, in allusion to the snout stripe of the species.
Original description: Trimma nasa Winterbottom, 2005 - Type locality: Tonga Point, 9°12'N, 123°28'E, Siquijor Island, Philippines.

Distribution
Eastern Indian Ocean, western Pacific: Bali (Indonesia), east to Palau, Solomon Islands and Fiji, north to Philippines, south to Queensland (Australia) and New Caledonia.

Biology
Cryptobenthic, epibenthic. Collected on drop-offs, either sloping or vertical with caves. Apparently tends to congregate in loose schools close to the shelter of caves and sea fans, to which they retreat when approached.

Similar species
Trimma marinae (Winterbottom, 2005) - Reported from Eastern Indian Ocean, western Pacific: Bali (Indonesia) east to Palau, New Britain (Papua New Guinea) and Solomon Islands, north to Japan, south to Great Barrier Reef (Queensland, Australia). Trimma marinae is very similar to Trimma nasa, but has virtually no caudal spot and has a nasal pit rather than the nasal sac present in all other species of Trimma.
Trimma tevegae (Cohen & Davis, 1969) - Reported from New Caledonia - Link to the species (here). Second spine of first dorsal fin less elongated, not reaching beyond base of third ray of second dorsal fin; Anterior midline of head without a blue stripe (dark in preservative); A diffuse dark spot behind symphysis of lower jaw; Top and sides of snout densely pigmented with small, dark, rounded melanophores mixed with slightly larger, amorphous, lighter brown melanophores and a sprinkling of much larger, darker, rounded melanophores.

Last update: 8, April 2023