The onefin skate (Gurgesiella dorsalifera) is a species of fish in the family Gurgesiellidae. It is endemic to Brazil. Its natural habitat is open seas, specifically on the bottom along the continental slope between 400mand800mm (1,300feetand2,600feetm) deep. It is a bycatch of fishing boats targeting shrimp and Argentine squid (Illex argentinus), which has contributed to significant population declines among G. dorsalifera.