Distinctive Characters: Head with 7 gill slits. Head and snout very narrow. Eyes very large. Single dorsal fin. Large comb-like lower teeth, their inner edges with a few short cusplets but no serrations.
Colour: Dark. Black tips to dorsal and upper caudal, especially prominent in young ones.
Habitat and Biology: Benthic, on the continental and insular shelves and upper slopes. Depths usually between 27-720 m. But sometimes in shallower water close inshore and down to 1000 m. Ovoviviparous, number of young 9 to 20 per litter.
Distribution: Widespread in temperate and tropical waters.
Remarks: One specimen of Heptranchias perlo (4.2 kg) was caught by bottom trawl in 240 m near a
Thoddo on 22.8.83 by the Norwegian research vessel Dr ‘Fridtjof Nansen’