Beachrock Mangrovegoby, Mugilogobius littoralis Larson 2001

Other Names: Beachrock Mangrove Goby, Seep Goby

Summary:

A small dusky grey goby with a blunt snout, irregular dark brown bars, spots and blotches, and a whitish to yellow submarginal band on first dorsal fin.

Cite this page as:

Martin F. Gomon, Mugilogobius littoralis in Fishes of Australia, accessed 18 Apr 2024, https://fishesofaustralia.net.au/home/species/2246

Beachrock Mangrovegoby, Mugilogobius littoralis Larson 2001

More Info

Distribution	Confined to tropical northern Australia from Shark Bay, WA to Bing Bong Creek, Gulf of Carpentaria, NT; a benthic species in the intertidal zone of rocky shores; typically found in rock pools near freshwater seepages, in brackish pools behind beach dunes or in sandy mangrove lagoons along beaches.
Features	Meristic features: Dorsal fin V-VI; I,7-9; Anal fin I,7-9; Caudal fin (segmented rays) 15-16, (branched rays) 13-16; Pectoral fin 13-16; Pelvic fin I, 5; Gill rakers 3-4 + 8-9 = 11-13; Vertebrae 10-11+15-17 = 16-17. Body slender, compressed, less so anteriorly; depth 4.5–6.8 in SL; caudal peduncle compressed. Head somewhat depressed, length 3.0-4.3 in SL. Snout slightly pointed to rounded, tip slightly inflated but not overhanging upper lip. Anterior nostril in a short tube on edge of upper lip, directed down and forward, preorbital curved forward to accommodate nostril; posterior nostril round to oval, close to anterior margin of eye. Eyes dorsolateral, high on head, top forming part of dorsal profile, 2.7-4.4 in HL; interorbital broad, flat to slightly concave; top of head, occasionally covered with very small, sparsely scattered villi. Mouth subterminal, slightly oblique; reaching about to below middle of eye or slightly less so; little sexual dimorphism; lips usually smooth; lower lip free at sides, fused across front; chin smooth; tongue tip blunt to slightly concave; jaw teeth in 4-5 rows, outer row in upper jaw largest, curved and pointed, others in both jaws small and sharp; teeth in females similar to males, but smaller and less curved. Gill opening restricted to pectoral base or extending forward to just under opercle; inner edge of pectoral girdle with low knobby or fleshy ridge or narrow irregular flange or with distinct fleshy knobs or flaps. Body fully scaled, ctenoid scales reaching forward in narrow wedge from caudal base to just below fourth ray of second dorsal fin or to gap between dorsals, and in isolated oval patch behind pectoral fin; lateral line absent; longitudinal series 36-46; evenly small predorsal scales, 12-21, usually forward to above preopercular margin, those near dorsal midline slightly farther forward; but not to behind eyes; upper two-thirds of operculum with small cycloid scales; cheek naked; pectoral base covered with small cycloid scales; prepelvic area covered with small cycloid scales; belly with isolated patch of ctenoid scales under pelvics, others cycloid. Head pores absent. Two dorsal fins, first low, triangular to somewhat rounded, spines falling short of second dorsal fin origin when depressed, gap of 3-4 scales between dorsal fins; second dorsal fin taller than or equal in height to first. Anal fin lower than dorsals; last rays of second dorsal and anal fins falling well short of caudal fin base when depressed. Pectoral fin broad, rounded. all rays but first branched. Pelvic fins fully united into disc, short, rounded to oval, reaching about half way to anus. Caudal fin short rounded.
Size	To around 5.5cm SL
Colour	Translucent grey or greyish yellow, with irregular pale grey bars and blotches, and scattered whitish patches of varying intensity; some with 7-10 saddles or pairs of grey blotches on either side of mid-dorsal line; markings on sides variable, usually rounded large dusky patches or blotches, though some without clear markings and others with grey reticulation or spotting; narrow grey scale margins on large fish; top of abdominal cavity, whitish, with blackish dorsal midline and black blotches; nape, shoulder and top of head reaching onto snout with irregular dusky pattern; dark oblique bar on shoulder; small black spot crossing top of caudal peduncle, at base of uppermost few caudal rays. Side of head greyish with 3 distinct oblique blackish stripes crossing preorbital and cheek. First dorsal fin with grey margin, grey to black edged orange or yellow submarginal stripe and pale grey on lower third of fin; second dorsal translucent to greyish with narrow dark grey margin and pinkish orange submarginal stripe. Caudal fin plain translucent greyish to whitish, with diffuse dusky spot at fin base, short vertical bar on fin close to base in large fish.
Species Citation	Mugilogobus littoralis Larson, 2001, Rec. West. Aust. Mus. Suppl. 62: 139, figs 123, 133–136. Type locality: Nightcliff Boat Ramp, Darwin, NT.
Author	Martin F. Gomon

Beachrock Mangrovegoby, Mugilogobius littoralis Larson 2001

References

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Perth : Western Australian Museum 394 pp.

Larson, H.K. 2001. A revision of the gobiid fish genus Mugilogobius (Teleostei: Gobioidei), and its systematic placement. Rec. West. Aust. Mus. Suppl. 62: 1–233.