Author: Fowler, 1941
Field Marks:
Sharks with elongate, catlike eyes with nictitating eyelids, nostrils without barbels or nasoral grooves, mouth long and angular, arched and reaching past anterior ends of eyes, labial furrows very short or absent, small cuspidate teeth, two small, spineless dorsal fins and anal fin, the first dorsal base well ahead of pelvic bases, no precaudal pits, and the caudal fin without a strong ventral lobe or lateral undulations on its dorsal margin.
Diagnostic Features:
Head without laterally expanded blades; eyes elongated and fusiform, oval, or slitlike, with lengths over 2 times height; nictitating eyelids rudimentary; spiracles present and moderately large; anterior nasal flaps broadly angular, not barbel-like; internarial width about 0.5 to 1.9 times nostril width; labial furrows absent or very short; teeth small, with acute narrow cusps, often lateral cusplets, and strong basal ledges and grooves, not bladelike and similar in both jaws; posterior teeth comblike; tooth rows 46 to 99/49 to 114. Precaudal pits absent. First dorsal fin small and not keel-like, much shorter than caudal fin; first dorsal base well ahead of pelvic bases, but usually closer to pelvic bases than to pectorals; midpoint of first dorsal base always in front of pelvic origins; pectoral fins with radials confined to bases of fins; ventral caudal lobe absent or very weak; no undulations or ripples in dorsal caudal margin. Neurocranium with supraorbital crests; vertebral centra without strong, wedge-shaped intermedial calcificiations. Valvular intestine with a spiral valve of 6 to 11 turns. Some species with variegated colour patterns, others without them. Development oviparous or ovoviviparous.
Habitat, Distribution and Biology:
This is a small family of poorly-known, deepwater sharks with a disjunct distribution in tropical to warm temperate waters of the western North Atlantic and Indo-West Pacific. Finback catsharks live on the outer continental and insular shelves and upper slopes, on or near the bottom, at depths of 50 to 713 m. Their size is small; none exceed 1.2 m, and one species, Eridacnis radcliffei, is one of the two smallest sharks known. Most of the species are ovoviviparous, except for the oviparous Proscyllium habereri. Food of these harmless sharks consists of small fishes and invertebrates.
Interest to Fisheries:
Minimal, a few species are taken by commercial bottom trawlers, but their small size makes them unsuitable for fisheries utilization other than for fishmeal.
Remarks:
The arrangement of this family follows Compagno (1979).