Scopeloberyx robustus

Common Name

Longjaw Bigscale

Year Described

G√ľnther, 1887

Identification

Dorsal Fin: II-III, 10-12
Anal Fin: I, 7-9
Pectoral Fin: 12-15
Pelvic Fin: I, 7-8
Caudal Fin: 9-10 branched, 2-4 procurrent rays
Lateral Scale Rows: 28-33
Gill Rakers: 19-22
Vertebrae:

Head with numerous bony ridges and pits. No post-temporal spines, projecting anterior spines, or raised bony crest on top of head. Preopercle and opercle margins relatively smooth or with weak spination. Gill rakers in first arch relatively numerous (20 or more). Anal fin origin varies from before to behind the last dorsal fin ray. Pectoral fin reaches last ray of dorsal fin. Pelvic fin origin well behind pectoral fin origin. Body scales large and easily shed.

Color

Uniformly brown

Size

Maximum size to 73mm SL

Habitat

Captured at depths between 0-4000m. Adults found in deeper water under 500m while juveniles are captured up to the surface at night.

Range

Widespread in the north Atlantic from off Canada to the Caribbean Sea, including the Gulf of Mexico. Also off Brazil.

References

Bartow, K. W. 2010. Taxonomy and Ecology of the Deep-Pelagic Fish Family Melamphaidae, With Emphasis on Interactions With a Midocean Ridge System. Unpublished PhD dissertation, Florida Atlantic University.

Keene M. J. 1987. Systematics and distribution of the deep-sea fish family Melamphaidae in the Atlantic Ocean. Unpublished Ph.D. dissertation, University of Rhode Island.

Kotlyar, A. N. 2004. Revision of the genus Scopeloberyx (Melamphaidae). Part 1. Multi-raker species of the group S. robustus. Journal of Ichthyology. v. 44 (no. 8): 537-554.

McEachran, J.D. and J.D. Fechhelm. 1998. Fishes of the Gulf of Mexico. Volume 1: Myxiniformes to Gasterosteiformes. University of Texas Press, Austin. i-viii + 1-1112.

Mincarone, M. M., F. Di Dario and P. A. S. Costa. 2014. Deep-sea bigscales, pricklefishes, gibberfishes and whalefishes (Teleostei: Stephanoberycoidei) off Brazil: new records, range extensions for the south-western Atlantic Ocean and remarks on the taxonomy of Poromitra. Journal of Fish Biology v. 85: 1546-1570.

Moore, J. A., K. E. Hartel, J. E. Craddock, and J. K. Galbraith. 2003. An annotated list of deepwater fishes from off the New England region, with new area records. Northeastern Naturalist 10(2): 159-248.

Other Notes

Keene (1987) described Scopeloberyx americanus from the northern Atlantic but this remains unpublished. The species was diagnosed by having a gill raker count of 20-23 which is within the diagnosis of S. robustus in Kotlyar (2004). The related Scopeloberyx rubriventer is diagnosed by Kotlyar (2004) with 23 gill rakers in the first arch, but only based on 5 juvenile specimens. The juvenile specimens may explain the uniserial teeth that are supposed to separate the species. Additional specimens of S. rubriventer from off the Bear Seamounts (Moore et al., 2003) were captured but no meristic information was provided, and “Scopeloberyx sp.” was also included that corresponded to the unpublished S. americanus. Given Keene’s (1987) " Scopeloberyx americanus " matches the diagnosis of S. robustus in Kotlyar (2004), the identity and validity of S. americanus is not known. The diagnosis of S. robustus in Bartow (2010) has higher gill raker counts than Kotlyar’s (2004) diagnosis of S. robustus, and is closer to S. rossicus or S. rubriventer. It is possible that Scopeloberyx americanus is attributable to S. robustus, and the higher gill raker count specimens are S. rubriventer, or that an additional species is actually present with these two species. Additional information is needed on Atlantic S. robustus complex material.

The status of Keene’s “Scopeloberyx congergencus”, as well as his Atlantic records of S. microlepis, S. nigrescens, and S. opercularis need to be confirmed. They would key to the multi-rakered relatives of the S. robustus group.