Six- and Sevengill SharksSix- and Sevengill Sharks

HexanchidaeHexanchidae

Diagnostic FeaturesDiagnostic Features• Body cylindrical and moderately slender to Body cylindrical and moderately slender to

snout with no abdominal keelssnout with no abdominal keels

• 6 or 7 pairs of gill slits not connected across 6 or 7 pairs of gill slits not connected across throatthroat

• Mouth subterminal on snoutMouth subterminal on snout

• Teeth in upper and lower jaws differentiatedTeeth in upper and lower jaws differentiated

• Anal fin smaller than dorsalAnal fin smaller than dorsal

• Caudal fin with strong subterminal notchCaudal fin with strong subterminal notch

• Can be 4.5’ to 16’ max length at maturityCan be 4.5’ to 16’ max length at maturity

Teeth StructureTeeth Structure

Habitat and DistributionHabitat and Distribution• Boreal and cold temperate to tropical Boreal and cold temperate to tropical

seasseas

• Most species deepwater, some in Most species deepwater, some in bays and close inshorebays and close inshore

Feeding HabitsFeeding Habits• SharksSharks

• RaysRays

• Large bony fishesLarge bony fishes

• CrustaceansCrustaceans

• Carrion—sometimes mammalsCarrion—sometimes mammals

EcologyEcology• OvoviviparousOvoviviparous

– 6-12 pups per litter6-12 pups per litter– Lack yolk-sac placentaLack yolk-sac placenta

GeneraGenera• HexanchusHexanchus

• HeptranchiusHeptranchius

• NotorynchusNotorynchus

HexanchusHexanchus• Head broad or narrow and pointedHead broad or narrow and pointed

• Six pairs of gill slitsSix pairs of gill slits

• No spots on bodyNo spots on body

• No black tipped finsNo black tipped fins

• Max length: 6’ to 16’Max length: 6’ to 16’

HeptranchiasHeptranchias• Head narrow, pointedHead narrow, pointed

• Seven pairs of gill slitsSeven pairs of gill slits

• Large eyesLarge eyes• Mouth narrow and parabolic Mouth narrow and parabolic (bowl shaped)(bowl shaped)

• Spots absent from bodySpots absent from body

• Caudal peduncle longCaudal peduncle long

• Black-tipped fins very noticeable in Black-tipped fins very noticeable in juvenilesjuveniles

• Max length: 4.5’Max length: 4.5’

NotorynchusNotorynchus• Head broad and rounded or bluntly pointed Head broad and rounded or bluntly pointed

• Seven pairs of gill slitsSeven pairs of gill slits

• Small eyesSmall eyes

• Mouth wide and arc-edMouth wide and arc-ed

• Caudal peduncle shortCaudal peduncle short

• Body with small black spotsBody with small black spots

• Dorsal and upper caudal lobe without black Dorsal and upper caudal lobe without black tipstips

• Max length: 10’Max length: 10’

Related ArticlesRelated Articles• ADNET S (2006) Biometric analysis of the teeth of fossil and ADNET S (2006) Biometric analysis of the teeth of fossil and

Recent hexanchid sharks and its taxonomic implications. Acta Recent hexanchid sharks and its taxonomic implications. Acta Palaeontologica Polonica: Vol. 51, No. 3 pp. 477-488. Palaeontologica Polonica: Vol. 51, No. 3 pp. 477-488.

• DUNBRACK R and ZIELINSKR (2005) Body size distribution DUNBRACK R and ZIELINSKR (2005) Body size distribution and frequency of anthropogenic injuries of Bluntnose Sixgill and frequency of anthropogenic injuries of Bluntnose Sixgill Sharks, Sharks, Hexanchus griseusHexanchus griseus, at Flora Islets, British Columbia. , at Flora Islets, British Columbia. Canadian Field-Naturalist: Vol. 119, No. 4 pp. 537-540. Canadian Field-Naturalist: Vol. 119, No. 4 pp. 537-540.

• LUCIFORA LO, et al (2005) Reproduction, abundance and LUCIFORA LO, et al (2005) Reproduction, abundance and feeding habits of the broadnose sevengill shark feeding habits of the broadnose sevengill shark Notorynchus Notorynchus cepedianuscepedianus in north Patagonia, Argentina. Marine Ecology- in north Patagonia, Argentina. Marine Ecology- Progress Series: Vol. 289, pp. 237-244. Progress Series: Vol. 289, pp. 237-244.

• MAISEY JG (2004) Morphology of the Braincase in the MAISEY JG (2004) Morphology of the Braincase in the Broadnose Sevengill Shark Broadnose Sevengill Shark NotorynchusNotorynchus (Elasmobranchii, (Elasmobranchii, Hexanchiformes), Based on CT Scanning. American Museum Hexanchiformes), Based on CT Scanning. American Museum Novitates: Vol. 3429, No. 1 pp. 1–52. Novitates: Vol. 3429, No. 1 pp. 1–52.

Works CitedWorks Cited

• Compagno, L.J.V., 1984. FAO species catalogue. Vol. 4. Compagno, L.J.V., 1984. FAO species catalogue. Vol. 4. Sharks of the world. An annotated and illustrated Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 1 - catalogue of shark species known to date. Part 1 - Hexanchiformes to Lamniformes. FAO Fish. Synop. Hexanchiformes to Lamniformes. FAO Fish. Synop. 125(4/1):1-249. 125(4/1):1-249.