Ancistrogobius dipus Shibukawa, Yoshino & Allen, 2010
Double-fin cheek-hook goby
Ancistrogobius dipus
photo by Allen, G.R.

Family:  Gobiidae (Gobies), subfamily: Gobiinae
Max. size:  4.24 cm SL (male/unsexed)
Environment:  benthopelagic; marine; depth range 15 - 35 m
Distribution:  Western Pacific: Japan to the Great Barrier Reef.
Diagnosis:  Dorsal spines (total): 7-7; Dorsal soft rays (total): 9-10; Anal spines: 1-1; Anal soft rays: 9-9. This species is unique from its congeners by having the following characters: largely separated pelvic fin with rudimentary connecting membrane and no frenum; fifth segmented ray of pelvic fin short, length 67.9-71.9% of preceding ray; a narrow black blotch on distal tip of first dorsal fin (not reaching posteriorly to third spine); pectoral-fin rays 19-21, usually 20; head and most of nape naked, no predorsal scales (except for one specimen, WAM-P.32537-001, with one predorsal scale); third spine of first dorsal fin greatly elongated, filamentous, obviously longer than preceding spine, typically with alternating pale and dusky (or yellow) bands when alive or fresh; faint, dusky blotches (not forming distinct vertical bar) below eye; sensory papilla x^1 and x^2 not continuous, interrupted by row trp; sensory papilla rows trp long, extending dorsally to well above a longitudinal line through row x^1; anterior tip of sensory papilla row b meeting row 4; sensory papilla row 4 long, dorsal tip close to eye; possess a relatively slender and pointed snout (this character difficult to quantify) (Ref. 84001).
Biology:  Collected from sandy-mud or silt bottoms with dead-coral rubble at depths of 15-35 m (Ref. 84001).
IUCN Red List Status: Least Concern (LC); Date assessed: 14 August 2023 Ref. (130435)
Threat to humans:  harmless


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