The whitetail dogfish is a rare species known only from a few specimens taken by tunalongliners and trawlers. The dorsal fins are small, the pectoral fins are angular, and there is an asymmetric caudal fin with a dark-tipped upper lobe. Coloration is grey and white, mottled with large brown or black spots, the tail mostly white with black tips.
The whitetail dogfish is ovoviviparous, with at least 59 pups per litter.[2]