As the standard name implies, the Humpback Scorpionfish has a hunched appearance. The species occurs in tropical and subtropical waters of the Indo-Pacific.
The Humpback Scorpionfish is one of five known humpback species of Scorpaenopsis that are characterized by a highly arched back below the spinous part of the dorsal fin, a broad interorbital space and a divided upper opercular spine.
The four other humpback species are S. diabolus, S. gibbosa, S. neglecta and S. obtusa. With the exception of S. neglecta, S. macrochir is easily distinguished from other humpback species by the colour pattern on the inside of the pectoral fin. Both S. macrochir and S. neglecta lack a large black spot (larger than the orbit diameter) on the middle of the inside of the pectoral fin, which is present in the other three species.
Scorpaenopsis macrochir is very similar to S. neglecta, but differs by the presence of two to six points on the nasal spine (versus serrations in S. neglecta). It can also be distinguished from S. neglecta by the relative positions of the bulge on the snout and the posterior nostrils. The posterior margin of the bulge in S. macrochir extends well beyond the level of the posterior nostrils, whereas in S. neglecta the bulge does not extend beyond the level of the posterior nostrils.
The species is found in depths less than 80 m.
The Humpback Scorpionfish is widely distributed in tropical and subtropical waters of the Indo-Pacific. It is common in Australian waters of Northern Western Australia to northern New South Wales.
The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Source: Atlas of Living Australia.
Ozcam map of Humpback Scorpionfish specimens in the Australian Museums. http://ozcam.ala.org.au/occurrences/search?q=Scorpaenopsis%20macrochir&zoom=off#mapView
- Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.
- Motomura, H., Yoshino, T. & N. Takamura. 2004. Review of the scorpionfish genus Scorpaenopsis (Scorpaeniformes: Scorpaenidae) in Japanese waters with three new records and an assessment of standard Japanese names. Japanese Journal of Ichthyology, 51(2): 89-115.
- Randall, J. E. & W.N. Eschmeyer. 2001. Revision of the Indo-Pacific scorpionfish genus Scorpaenopsis, with descriptions of eight new species. Indo-Pacific Fishes. 34: 1-79, pls. 1-12.