Bathygobius soporator (Valenciennes, 1837)
Frillfin goby
Bathygobius soporator
photo by Joyeux, J.-C.

Family:  Gobiidae (Gobies), subfamily: Gobiinae
Max. size:  15 cm TL (male/unsexed)
Environment:  demersal; freshwater; brackish; marine; depth range 0 - 16 m, non-migratory
Distribution:  Eastern Atlantic: Senegal to Angola (Ref. 5299, 57403, 79590) including the islands of the Gulf of Guinea (Ref. 79590). Western Atlantic: Florida Keys in the USA, Bermuda and the Bahamas to Santa Catarina, Brazil (Ref. 7251, 57756). Mediterranean Sea (Ref. 50345). Suspected to be conspecific with Bathygobius fuscus. Record from Algeria needs confirmation (Ref. 2682).
Diagnosis:  Dorsal spines (total): 7-7; Dorsal soft rays (total): 8-9; Anal spines: 1-1; Anal soft rays: 7-9. Diagnosis: body with 3 broad, oblique, dark cross bars; numerous pale striae along sides, corresponding to the center of each longitudinal scale row; head and pectoral-fin bases with white spots and mottling; predorsal scales extend well anterior to level of preoperculum, and anterior margin of scaled area appears convex in dorsal view (Ref. 57403, 79590). 4-5 outer/upper pectoral-fin rays free (Ref. 57403, 79590), hence its name "Frillfin goby" (Ref. 26938). Body shape is terete, slightly depressed; eyes situated dorso-laterally; reduced swim bladders (Ref. 92840). Description: predorsal scales extending anteriorly beyond level of preopercle, towards rear edge of orbit, with anterior margin of scaled area convex in dorsal view (Ref. 79590). 16-27 (usually 18-24) predorsal scales; 33-40 (usually 36 or 37) scales in a longitudinal series (including 3-5 scales on caudal fin base), 12-14 (usually 13) scales in rearward transverse series; 1st dorsal fin: VI; 2nd dorsal fin: I,8-9; anal fin I,7-9 (usually 8); pectoral fins: 18-21 (usually 19 or 20), 4-5 outer (dorsal) ones free; caudal fin: 14 or 15 branched rays (Ref. 57403, 79590). Coloration: Preserved specimens: 3 broad, oblique cross bars on body, middle one often paler than others; flanks with numerous pale striae, corresponding to scale centers of each longitudinal scale row (less distinct in large individuals); head with dark mottling, including intense dark spot behind eye and a more diffuse spot above preoperculum; cheeks, operculum and pectoral-fin bases covered with pale spots; faint lateral pre- and suborbital bands present; distal area of 1st dorsal fin pale, middle part with a broad dark band; 2nd dorsal fin with dark, oblique bands, sometimes confluent, and more intense posteriorly; anal fin dark, in particular posteriorly; bases of pectoral fins with upper and lower areas dark; pelvic dark with a paler rim; caudal fin with 3-4 concentric dark bands (Ref. 57403, 79590). In life: margins of both dorsal fins pink; 1st ray of 2nd dorsal fin with 3 black spots; ventral rays of caudal fin olivaceous green; spots on body olivaceous to black (Ref. 57403, 79590).
Biology:  A resident intertidal species with homing behavior (Ref. 32612). Lives benthically over sandy and muddy substrates (Ref. 79590). Mainly found in pools (Ref. 4343). Abundant in rocky tide pools and along water's edge (Ref. 7251) in lagoons, creeks, estuaries (Ref. 5299, 57403, 79590) and (mangrove) swamps (Ref. 57403, 79590). Occasionally found in fresh waters (Ref. 57403, 79590), with salinity range of 0.0-38.8 ppt (Ref. 97140). Maximum standard length reported 113 mm (= 145 mm TL)(Ref. 79590).
IUCN Red List Status: Least Concern (LC); Date assessed: 11 February 2019 Ref. (130435)
Threat to humans:  harmless


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