Smallhead Grunter, Scortum parviceps (Macleay 1883)


Other Names: Small Headed Grunter, Small-headed Grunter

Smallhead Grunter, Scortum parviceps. Source: John Merrick. License: all rights reserved

Summary:
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Cite this page as:
Martin F. Gomon, Scortum parviceps in Fishes of Australia, accessed 15 Nov 2018, http://fishesofaustralia.net.au/home/species/703

Smallhead Grunter, Scortum parviceps (Macleay 1883)

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Distribution

Known only from the upper Burdekin River, QLD (19º53´S, 146º14´E); a tropical species inhabiting swift flowing, clear freshwater streams, near rapids; swims close to the bottom.

Features

D XIII, 10-11; A III, 9; P 15-16; V I, 5; LL 49-53; Trv Sc 8-10/1/20-22; GR 9-10+1+18-22; Vert 11+14.
Body moderately deep, 2.6-2.9 in SL, ovate, compressed. Dorsal profile straight or slightly convex to nape, then straight to origin of dorsal fin. Dorsal profile much more pronounced than ventral. Ventral profile straight to isthmus; slightly convex from isthmus to insertion of pelvics, then straight from insertion to anus. head length 3.0-3.5 in SL; snout length 3.0-3.5 in HL; eye width 3.7-5.0 in HL; jaw length 3.4-3.8 in HL; Jaws equal, lower jaw slightly flattened, with teeth projecting slightly outward. Gape horizontal. Snout elongate. Maxillary reaching to vertical through anterior of eye in young, falling short with age, reaching only to vertical through posterior nostril. Teeth slightly flattened, depressible with outer row enlarged. Young with vomerine teeth. Vomers and palatines smooth in adults (some adults with one or two vomerine teeth). Interorbital region smooth. Nostrils separated by a distance equal to or slightly greater than diameter of posterior nostril. Lacrimal serrate in young; serrations reduced in adults. Preoperculum serrate; serrations largest on angle. Lower opercular spine stronger and longer; not extending beyond edge of opercular lobe. Cleithrum exposed; serrate posteriorly; scales on side. Supracleithrum exposed. Posttemporal exposed; serrate along posterior edge.
Scales finely ctenoid; lateral line continuous, smoothly curved; 3-4 scales on caudal; 51-61 scales above lateral line; 8-10 scales below lateral line; 16-20 predorsal scales to occiput; two rows of scales in sheath at base of dorsal, sheath extending to seventh or eighth dorsal ray; 3-4 rows of scales in sheath at base of anal, sheath extending across base of all rays; cheek scales in 4-6 rows.
Dorsal fin continuous, base 1.65-1.8 in SL; spinous portion arched; first spine very short; fifth or sixth spines longest, 1.8-2.0 in HL, those following decreasing in length to penultimate which is approximately as long as ultimate. Longest dorsal spine longer than longest dorsal rays; longest dorsal ray 1.8-2.0 in HL; soft dorsal angular; posterior border straight. Second and third anal spines subequal; longest shorter than longest anal rays, longest anal spine 2.2-2.5 in HL; longest anal ray 1.6-1.7 in HL, posterior margin of soft anal obliquely truncate or slightly convex. Pectoral fins asymmetrically pointed; first ray longest and slightly filamentous; reaching to anus; falling short with age. Caudal fin deeply emarginate.

Size

To 38 cm SL.

Colour

Body darker above, with random dark blotches on sides; edges of scales more heavily pigmented. Head darker above, pale below; band from tip of snout to lower margin of eye. Opercular membranes heavily pigmented around lower opercular spine. Spinous porstion of dorsal fin with pigmentation more pronounced along anterior edges of spines; soft dorsal dusky with paler margins. Anal fin dusky, margin much lighter. Caudal clear to dusky with pale margin. Pectoral fins dusky. Pelvic fins yellowish.

Feeding

Omnivorous, feeding on algae, fishes, crustaceans, insects and molluscs.

Biology

Oviparous pelagic spawners; breeding is thought to occur between October and November. Eggs pelagic, large 4.2-4.3 mm. Larvae hatch after 36 hours.

Etymology

The species name parviceps, from the Latin parvus, small, and new Latin ceps, head, refers to the relatively small head of this species in comparison to those of other members of the genus.

Species Citation

Therapon parviceps Macleay, W.J. (1883). Notes on a collection of fishes from the Burdekin and Mary Rivers, Queensland. Proc. Linn. Soc. N.S.W. (1)8(2): 199–213 [201]. Upper Burdekin River, QLD.

Author

Martin F. Gomon

Smallhead Grunter, Scortum parviceps (Macleay 1883)

References


Allen, G.R., Midgley, S.H. & Allen, M. (2002). Field guide to the freshwater fishes of Australia.  Perth : Western Australian Museum 394 pp.

Pusey B., Kennard M. & Arthington A. (2004) Freshwater Fishes of North-Eastern Australia. CSIRO Publishing Collingwood, Victoria. 684 pp.

Vari, R.P. (1978). The terapon perches (Percoidei, Terapontidae) a cladistic analysis and taxonomic revision. Bull. Amer. Mus. Nat. Hist. 159(5): 175–340 figs 1–94 [302].

Quick Facts


CAAB Code:37321027

Habitat:clear freshwater streams

Max Size:38 cm SL

Native:endemic

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