shark shark species requiem shark family found western atlantic_ocean northern gulf_of_mexico southern brazil inhabits shallow waters close shore particularly muddy bottoms tends swim low water column forms large segregated sex slim species generally exceeding length shark long pointed snout broad triangular dorsal fin second dorsal fin originates anal fin base plain gray color prominent markings fins diet shark consists mainly bony fishes crustaceans cephalopods smaller sharks rays consumed viviparous meaning developing embryos sustained connection females bear litters young cycle following approximately month gestation period shark caught meat fins liver oil impact fishing population largely unknown northern brazil declined significantly 1980s listed overall vulnerable brazil taxonomy phylogeny italian naturalist published scientific description shark volume named new shark greek referring prominent pores eyes type specimen male brazil lost species moved genus later authors shark evolutionary relationships shark uncertain based morphology tentatively placed group defined shark shark grouping supported based phylogenetic analysis alternately phylogenetic study based nuclear mitochondrial genes found close relationships shark shark shark shark pacific shark mistakenly resurrected distinct taxon species closely similar known southeast_asia description shark slender bodied species fairly long pointed snout leading margin enlarged narrow pointed lobe large circular eyes equipped membranes series prominent pores mouth bears short furrows corners contains tooth rows jaws usually upper lower upper teeth tall triangular strong increasing oblique sides lower teeth comparatively narrower upright finer pairs gill slits short small pectoral fins shaped relatively pointed tips dorsal fin broad forming nearly triangle adults blunt apex originates pectoral fin rear tips second dorsal fin small originates anal fin base ridge dorsal fins pelvic fins small pointed narrowly rounded tips anal fin deep notch trailing margin caudal fin strong lower lobe longer upper lobe ventral notch near tip dermal denticles non overlapping horizontal ridges leading posterior teeth central longest shark plain gray slate whitish faint lighter stripe flanks pectoral dorsal caudal fins tips shark reaches maximum known length typical females grow larger males distribution habitat known range shark extends northern gulf_of_mexico southern brazil excluding caribbean islands aside trinidad center abundance northern brazilian coast common shark species reported east mississippi_river past years despite historical evidence nursery area louisiana shark usually found close waters deeper northern brazil environment characterized tides high reaching knots rainy season dry season temperature ranges favors areas muddy bottoms biology ecology shark forms large segregated sex males generally found deeper females feeds mainly bony fishes including sea shrimp crabs squid secondary food sources adults capable taking young sharks sharks habits composition shark generally reflects available environment northern brazil important prey species juveniles consume wider variety prey adults turn shark potentially preyed larger sharks like members family shark viviparous developing embryos exhaust supply yolk yolk sac develops connection mother delivers females produce litters typically young year litter size increases size female gestation period lasts approximately months reproduction occurs year peak september november known nursery areas shallow waters northern brazil trinidad bays provide shelter food measure long grow average year years life males females mature sexually long respectively corresponding years age sexes average growth rate year maturation maximum lifespan years human interactions harmless humans shark caught incidentally fisheries range meat sold fresh frozen dried addition dried fins exported use shark fin soup liver oil processed iucn assessed species including pacific populations separated lack fishery data trinidad abundance makes economically important shark northern brazil substantial numbers caught fisheries targeting spanish 1980s species constituted roughly shark ray catch declined apparent decline thought resulted increasing fishing effort large proportion juveniles captured shark low reproductive rate consequently iucn assessed shark brazil vulnerable noted urgent need conservation measures given northern brazil represents center species range shark ostensibly given protection inclusion official list endangered animals brazil fishing remains effectively
Smalltail shark