Puzzling Grouper, Hyporthodus perplexus (Randall, Hoese & Last 1991)

Other Names: Thompson's Rock-cod

Illustration of the holotype of Hyporthodus perplexus (originally described as Epinephelus perplexus), AMS E.2116, 465 mm SL, north-east of Cape Moreton, Queensland . Source: Roger Swainston, Fig. 6, in Randall, Hoese & Last (1993) Records Australian Museum 45: 25-31. License: CC By Attribution-NonCommercial-ShareAlike

A rare deepwater grouper known from a single specimen collected in about 130 m, NE of Cape Moreton, southern Queensland.
This species was previously placed in the genus Epinephelus.

Cite this page as:
Bray, D.J. 2018, Hyporthodus perplexus in Fishes of Australia, accessed 25 May 2024, https://fishesofaustralia.net.au/Home/species/3856

Puzzling Grouper, Hyporthodus perplexus (Randall, Hoese & Last 1991)

More Info


Known only from the holotype taken from north-east of Cape Moreton, southern Queensland, from a depth of about 130 m.


Dorsal fin XI, 13; Anal fin III, 8; Pectoral fin 18; Lateral-line scales 52 (not "about 83" as given by Whitley); longitudinal scale series 104; Gill rakers 10 + 17. 

Body depth 2.9 in SL; body width 1.6 in depth; head length 2.35 in SL; snout 3.8 in head; orbit diameter 6.0 in head; interorbital space slightly convex, the fleshy width 6.8 in head; suborbital depth 9.5 in head; least depth of caudal peduncle 3.65 in head. Mouth moderately large: maxilla nearly reaching a vertical through rear margin of orbit, its length 2.3 in head. Dentition typical of the genus; rows of teeth on side of lower jaw, the teeth of the inner row about twice as long as those of the outer row. Posterior nostril ovate, about twice as large as anterior nostril; membranous flap on rear edge of anterior nostril just reaching posterior nostril when adpressed. Middle opercular spine nearer lower than upper spine; margin of preopercle finely serrate, the corner with a prominent posterior bulge bearing 7 moderately enlarged serrae which seem to be somewhat worn; subopercle and interopercle not serrate. 
Scales ctenoid except on thorax and abdomen; no auxiliary scales on body; no small scales on maxilla. 
Third dorsal spine longest, 3.25 in head; sixth soft dorsal fin ray longest, 3.1 in head; second anal fin spine 4.1 in head; third soft anal fin ray longest, 2.9 in head; caudal fin slightly rounded, 2.2 in head; pectoral fins not fleshy, their length 2.05 in head; pelvic fins short, 2.5 in head. 


Colour in life unknown. Of the colour, Whitley (1948) wrote, "after long preservation in formalin, light brown. Margins of unpaired fins dark brown. A dark spot on each body-scale. No dark moustache or other conspicuous markings." 


This species is named perplexus due to its many peculiarities. 

Species Citation

Epinephelus perplexus Randall, Hoese & Last, in Randall & Heemstra 1991, Indo-Pacific Fishes 20: 222, fig. 116.  Type locality: 6.5 miles north-east of Cape Moreton, QLD. [Replacement name for Epinephelus thompsoni Whitley 1948 - junior secondary homonym of E. thompsoni (Fowler, 1923)].


Bray, D.J. 2018


Australian Faunal Directory

Puzzling Grouper, Hyporthodus perplexus (Randall, Hoese & Last 1991)


Craig, M.T., Sadovy de Mitcheson, Y.J. & Heemstra, P.C. 2011. Groupers of the World: a Field and Market Guide. Grahamstown, South Africa : NISC Ltd 356 pp., Appendix 47 pp. 

Craig, M.T. & Hastings, P.A. 2007. A molecular phylogeny of the groupers of the subfamily Epinephelinae (Serranidae) with a revised classification of the Epinephelini. Ichthyological Research 54(1): 1-17 

Heemstra, P.C. & Randall, J.E. 1993. Groupers of the World (Family Serranidae, Subfamily Epinephelinae). An annotated and illustrated catalogue of grouper, rockcod, hind, coral grouper and lyretail species known to date. FAO Fisheries Synopsis No. 125 Vol. 16. Rome: FAO. pp. 1-382 

Heemstra, P.C. & Randall, J.E. 1999. Family Serranidae. pp. 2442-2548 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 pp. 2069-2790. 

Randall, J.E., Hoese, D.F. & Last, P.L. 1993. On the status of the Australian serranid fishes Epinephelus ergastularius Whitley and E. thompsoni Whitley. Records of the Australian Museum 45: 25-31 PDF available, open access

Randall, J.E., Hoese, D.F. & Last, P.R. in Randall, J.E. & Heemstra, P.C. 1991. Revision of Indo-Pacific groupers (Perciformes: Serranidae: Epinephelinae), with descriptions of five new species. Indo-Pacific Fishes 20: 1-332 

Randall, J.E. & Heemstra, P.C. 1991. Revision of Indo-Pacific groupers (Perciformes: Serranidae: Epinephelinae), with descriptions of five new species. Indo-Pacific Fishes 20: 1-332 

Rhodes, K., Heemstra, P.C., Russell, B. & Pollard, D. 2008. Hyporthodus perplexus. The IUCN Red List of Threatened Species 2008: e.T64404A12776824. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T64404A12776824.en. Downloaded on 13 February 2018.

Whitley, G.P. 1948. Studies in Ichthyology No. 13. Records of the Australian Museum 22(1): 70-94 figs 1-11 (as Epinephelus thompsoni) PDF available, open access

Quick Facts

CAAB Code:37311153

Conservation:IUCN Data Deficient

Depth:129-137 m

Habitat:Reef associated

Max Size:46.5 cm SL/56.5 cm TL


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