Tadpole Goby, Chlamydogobius ranunculus Larson 1995


Tadpole Goby, Chlamydogobius ranunculus. Source: Glynn Ayland. License: All rights reserved

Summary:

A small goby usually found in freshwater floodplains and muddy mangrove creeks, as well as in drains and buffalo wallows.

Identifying features:
Males bluish-grey, darker above with dark scale margins; head and body with scattered black spots;
Outer half of first dorsal fin with a broad yellow band; basal half of second dorsal and anal fins bluish with a black central stripe and a broad white margin;
Females tannish.

Video of a Tadpole Goby in an aquarium


Cite this page as:
Martin F. Gomon & Dianne J. Bray, Chlamydogobius ranunculus in Fishes of Australia, accessed 29 Jan 2020, http://136.154.202.208/home/species/1327

Tadpole Goby, Chlamydogobius ranunculus Larson 1995

More Info


Distribution

Known from coastal areas of northern Australia between about Darwin and the Adelaide River, Northern Territory, to Bowen and Hinchinbrook Island, Queensland. 

The Tadpole Goby inhabits inshore estuarine, mangrove and freshwaters. It is usually found amongst mangroves and ponds in freshwater to brackish habitats.

Features

Meristic features:
Dorsal-fin spines/rays: V-VI; I, 6-8
Anal-fin spines/rays: I, 5-7
Pectoral-fin rays: 11-13
Caudal-fin rays: (segmented rays) 15-17 (branched rays) 11-16
Pelvic-fin spines/rays: I, 5
Vertebrae: 10-11 + 16-18 = 26-29
Gill rakers: 1-4 + 6-7 = 7-11

Body compressed, less so anteriorly. Head rounded, length 3.0-3.6 in SL. Snout somewhat steep, rounded, sometimes inflated and partially overhanging upper lip. Anterior nostril in short tube on preorbital edge just behind upper lip, tube oriented down and forward, preorbital curved forward to accommodate nostril. Posterior nostril small, rounded to oval, halfway between front margin of eye and preorbital.  Eyes lateral, high on head, top usually part of dorsal profile, 2.8-4.6 in HL. Interorbital broad, flat; top of head, from rear of interorbital space up to snout tip sometimes with very fine dark-pigmented villi. Lips usually smooth, lower lip free at sides, fused across front. Mouth terminal to subterminal, somewhat oblique, generally reaching to below mid-eye in both sexes, to front half of eye in smaller females; teeth of upper jaw in 3-4 rows, outermost larger than others, stout and curved or almost upright, others slightly smaller; teeth of lower jaw in 2-3 rows; tips of teeth in both jaws often tinted orange to honey brown; teeth similar in males and females; tongue broad, concave to bluntly rounded. Gill opening restricted to pectoral base; inner edge of shoulder girdle smooth.

Ctenoid scales on side of body in narrow wedge along midline, or in  patch behind pectoral fin and others from below second dorsal fin origin or posteriorly on caudal peduncle, ctenii weak; predorsal scales evenly small, cycloid, reaching forward to above preopercular margin or slightly further, 3-20 in front of dorsal; operculum with patch of small cycloid scales on upper third to half; cheek naked; pectoral fin base covered with cycloid scales; prepelvic area naked, or with few cycloid scales before pelvics, occasionally completely covered with scales; belly usually with isolated patch of weakly ctenoid scales under pelvics, rest cycloid; some with entire belly cycloid.  Lateral line absent; lateral scale series 32-52. Head pores absent.

Two dorsal fins, first low, rounded, fin barely reach second dorsal origin when depressed in large males; First dorsal fin third and fourth spines longest or subequal; spines often slightly longer in males than females; in mature males, spines; fin usually falls short of second dorsal in females; second dorsal and anal fins low, posteriormost rays falling well short of caudal fin base when depressed. Pectoral fin rounded. Pelvic fins united into complete disc, short, usually oval, sometimes reaching half distance to anus. Caudal fin broad, rounded.

Colour

Translucent yellowish grey, underside whitish, upper half of peritoneum through body wall pinkish white overlain by diffuse blackish narrow bars, ventral half whitish; body with indistinct grey to darker yellowish grey saddles and mottling; diffuse greenish grey streak from behind eye along upper half of body to below origin of second dorsal fin; scattered scales along mid-side of body with bluish white spots. Top and upper sides of head with greenish grey spots, small blotches and vermiculate lines; lower half of opercle greenish silvery white; iris pale gold with narrow brown ring around pupil. Pectoral base pinkish white, greyish close to ray bases. First dorsal fin with narrow grey margin, broad greyish yellow band across distal half of fin; below this, bright pale blue rounded spot between fourth and sixth spines; lower half of fin translucent dusky grey; second dorsal translucent pale grey with pinkish white margin, lower half of fin irregularly marked with slightly darker greyish or pinkish white vermiculate lines or diffuse blotches. Anal fin dark grey with white margin, proximal half of fin with greyish white markings. Caudal fin translucent pale grey with white margin; most of fin with vertically aligned rows of small grey or white spots; diffuse greenish grey dark spot on either side of fin base. Pectoral fin membranes translucent; rays pale translucent grey. Pelvic fins dark grey.

Mature males brownish grey with pale yellowish white to whitish grey underside; 6-7 darker brownish grey bars or saddles across back to mid-side of body; posteriormost bars somewhat oblique; indistinct brownish grey spot at centre of caudal base. Head plain except for two diffuse dark bars from eye to upper lip and to behind rictus. First dorsal fin darker with brighter yellow submarginal band and blue oval spot, spot edged with black ventrally; second dorsal fin dark grey to blackish with broad white margin and greyish blue band basally; middle of fin with vertically oriented black blotches. Anal fin similar to second dorsal but without black blotches. Caudal fin grey with faint vertical oval dark blotch on each side of fin base; vertical rows of small dark spots and blotches on basal half of fin, more indistinct distally; narrow margin dull white. Pectoral fin translucent, with greyish to yellowish-white rays. Pelvic fins yellowish white.

Biology

Oviparous. Females lay 30 large eggs that are guarded by male. Hatching occurs after about nine days at 25°C.

Conservation

  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not Evaluated
  • Similar Species

    Differs from other species in the genus Chlamydogobius in usually having the second dorsal and anal fin-ray counts I, 6.

    Etymology

    The species name is from the Latin ranunculus, meaning tadpole, a resemblance to which this rather frog-headed goby displayed to the author upon first their encounter, at the edge of a drying-up water buffalo wallow.

    Species Citation

    Chlamydogobius ranunculus Larson, 1995, The Beagle 12: 38, figs 3–4, 11–12, pl. 2.
    Type locality: Beatrice Lagoon, Adelaide River drainage, Northern Territory.

    Author

    Martin F. Gomon & Dianne J. Bray

    Tadpole Goby, Chlamydogobius ranunculus Larson 1995

    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. No. 62):1-233.Larson, H.K. 1995. A review of the Australian endemic gobiid fish genus Chlamydogobius with descriptions of five new species. The Beagle. Rec. Mus. Art. Gall. N. Terr. 12: 19–51 figs 1–4 pls 1–2

    Larson, H.K. & Williams, R.S. 1997. Darwin Harbour fishes: a survey and annotated checklist. pp. 339-380 in Hanley, H.R., Caswell, G., Megirian, D. & Larson, H.K. (eds). The Marine Flora and Fauna of Darwin Harbour, Northern Territory, Australia. Proceedings of the Sixth International Marine Biology Workshop. Darwin : Museum and Art Gallery of the Northern Territory 466 pp.

    Quick Facts


    CAAB Code:37428305

    Fishing:Aquarium fish

    Habitat:Freshwater to inshore marine

    Max Size:3.8 cm SL

    Native:Endemic

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