Common Name
Nordenskjold's Bigscale
Year Described
Lönnberg, 1905
Identification
Dorsal Fin: III, 9
Anal Fin: I, 8-9
Pectoral Fin: 13-15
Pelvic Fin: I, 7
Caudal Fin: 9-11 branched, 3-5 procurrent rays
Lateral Scale Rows: 29-35
Gill Rakers: 24-29
Vertebrae: 27-28
Head with numerous bony ridges and pits. No post-temporal spines, projecting anterior spines, or raised bony crest on top of head. Preopercle and upper opercular margins with serrations. Gill rakers in first arch relatively numerous (20 or more). Anal fin origin under last few dorsal rays. Pectoral fin reaches last ray of dorsal fin. Pelvic fin origin slightly behind pectoral fin origin. Body scales large and easily shed.
Color
Uniformly brown to black
Size
Maximum size to 108mm SL
Habitat
Mesopelagic from 200-3000m. Adults are found more frequently in colder Antarctic waters while juveniles and larvae are collected into the subtropical boundary currents.
Range
Circumpolar: found mostly south of the Southern Subtropical Convergence off Uruguay and Argentina. Juveniles are most likely to be caught further north and adults are far more commonly caught south of the South Polar Front around Antarctica and the Scotia Arc.
References
Kotlyar, A. N. 2002. Sio nordenskjoldii (Melamphaeidae): morphology and distribution. Journal of Ichthyology v. 42 (no. 1): 28-36.
Other Notes
Sio kreffti (Keene, 1987), an unpublished species from the southern ocean, is of uncertain status.