false false shark species ground shark family sole member genus worldwide distribution commonly recorded close continental slopes depths reaching length heavy bodied shark readily identified elongated keel like dorsal fin long narrow eyes large mouth filled numerous tiny teeth usually dark brown color light gray muscles large liver false slow moving predator variety fishes invertebrates viviparous mode reproduction featuring unusual form developing embryos consume egg fragments released mother use yolk material external yolk later use species typically gives birth pups time presently lacks sufficient data assess conservation status false targeted fisheries commercially valuable caught incidentally low reproductive rate render susceptible population taxonomy phylogeny false described portuguese based account long adult male caught portugal thought specimen resembled member genus lacking membrane known species fact trait assigned new genus greek pseudo false time classified false specific comes greek small tooth common names species dumb shark japanese keel dorsal shark pacific populations false regarded separate species morphological comparisons failed find consistent differences leading conclusion species false closest relatives false share number morphological similarities phylogenetic analysis protein genes found genetic divergence taxa shark species genus result suggests unique traits false evolved relatively recently supports grouping family description soft bodied false broad head short rounded snout nostrils large flaps skin anterior narrow eyes twice long high equipped rudimentary membranes eyes large huge mouth arched bears short furrows corners rows tiny teeth jaw arranged straight lines upper jaw diagonal lines lower jaw tooth pointed central flanked smaller pairs gill slits fairly small pectoral fins small rounded fin rays near base dorsal fin highly distinctive long roughly equal caudal fin low resembling keel ship originates pectoral fin rear tips terminates pelvic fin origins second dorsal fin larger originates ahead anal fin fins positioned close caudal fin caudal fin long upper lobe ventral notch near tip indistinct lower lobe dermal denticles shaped like central ridge sparsely distributed skin species typically plain dark brown color fin margins individuals instead light gray irregular darker fine dots false grows long weight distribution habitat rarely encountered false caught locations scattered world indicating wide distribution western atlantic reported canada united_states cuba brazil eastern atlantic known waters iceland france portugal islands azores cape_verde records indian_ocean come madagascar mauritius indonesia australia pacific_ocean documented japan taiwan indonesia new_zealand inhabiting continental slopes false occurs depths recorded deep individuals occasionally relatively shallower waters continental shelf following submarine suffering abnormal condition false generally close sea floor found reefs biology ecology soft fins skin false suggest sluggish lifestyle enormous oil filled liver makes total weight allowing maintain near neutral little effort species likely captures prey quick bursts speed large mouth allowing consume food considerable size feeds mainly bony fishes snake takes shrimp likely examination stomach contents found surface dwelling fishes frigate specimen caught human garbage including potatoes pear plastic bag soft drink record false found bite marks great white shark unusual ground sharks false viviparous developing embryos practicing adult females single functional right functional female long found contain estimated averaging gestation developing embryos initially yolk later transition feeding egg fragments mother excess egg material embryo stored external yolk sac close birth embryo transfers yolk external yolk sac internal yolk sac serve post birth food reserve typical litter size pups litters possible gestation period probably longer year possibly lasting years measure long males females probably mature sexually long respectively human interactions false minimal economic value meat fins liver oil utilized okinawa oil traditionally seal hulls wooden fishing boats like sharks species thought highly susceptible slow reproductive rate rarely caught information available population listed
False catshark