Author: Chirichigno, 1973
Field Marks:
An unspotted, grey, rather stocky Mustelus with strongly cuspidate teeth, lanceolate denticles, short caudal peduncle, and broadly frayed posterior dorsal fin margins.
Diagnostic Features:
Body fairly stocky, almost humpbacked. Head fairly long, prepectoral length 20 to 24% of total length; snout moderately long and bluntly angular in lateral view, preoral snout 5.6 to 7.6% of total length, preorbital snout 6.7 to 8.5% of total length; internarial space very broad, 2.9 to 3.7% of total length; eyes fairly large, eye length 2 to 3.1 times in preorbital snout and 2.1 to 3.2% of total length; interorbital space moderately broad, 4.5 to 5.6% of total length; mouth moderately long, slightly longer than eye length and 2.6 to 3.7% of total length; upper labial furrows considerably longer than lowers and 2.6 to 3.7% of total length; teeth cuspidate and asymmetric, with a prominent primary cusp and low cusplets occasionally present; buccopharyngeal denticles confined to anterior fourth of palate and tongue tip. Interdorsal space 16 to 21% of total length; trailing edges of dorsal fins naked, with a conspicuous dark margin of bare ceratotrichia; first dorsal broadly triangular, with posteroventrally sloping posterior margin, midbase closer to pelvic bases than pectorals; pectoral fins fairly large, length of anterior margins 14 to 17% of total length, width of posterior margins 11 to 14% of total length; pelvic fins moderately large, length of anterior margins 7.1 to 9.4% of total length; anal firwheight 2.3 to 3.8% of total length; anal-caudal space less than or subequal to second dorsal height, and 4.7 to 7.4% of total length; ventral caudal lobe hardly falcate in adults. Crowns of lateral trunk denticles lanceolate, with longitudinal ridges extending their entire length. Skeleton not hypercalcified in adults; palatine processes of palatoquadrates usually subdivided at symphysis, with a short separate medial segment on each side; monospondylous precaudal centra 36 to 41, diplospondylous precaudal centra 47 to 55, precaudal centra 86 to 93. Colour uniform grey or grey-brown above, lighter below, no white or dark spots or dark bars. Development viviparous. Size moderate, adults 68 to 87 cm.
Geographical Distribution:
Eastern South Pacific: Peru to southern Chile.
Habitat and Biology:
A common offshore bottom-dwelling shark of the Pacific South American continental shelf, at depths of 16 to 211 m, but most common at 70 to 100 m. Prefers rocky bottom around islands. Viviparous, with 5 to 10 young per litter. Eats crabs, manis shrimp, and small bony fishes.
Size:
Maximum at least 87 cm (adult female), smallest adult male 68 cm, smallest adult female 74 cm; size at birth about 25 cm.
Interest to Fisheries:
A common species off Peru, and probably figuring in the landings of species of "tollo" there.
Type material:
Holotype: Instituto del Mar del Peru, IMARPE 1210, 645 mm adult male. Type Locality: Off Paita, Peru, 92 m depth.