The classification of shark species can be difficult. Sometimes juvenile and adult specimen of one species are considered different species (Zebra Shark). And sometimes a species is considered equal to another (the sister species birdbeak shark), but the same species found in another place (off Madeira) get its own name, until 3 years later both are deemed the same, new species – the rough longnose dogfish (Deania hystricosa).
The rough longnose dogfish is a medium sized (up to 43 in -110 cm- long) deep sea shark and has been found in the Eastern central and southeast Atlantic around Madeira, the Canary Islands, Namibia and South Africa and the Northwest Pacific around Japan and New Zealand (so far). The species belongs to the family gulper sharks and has got grooved spines in front of both dorsal fins and rough, pitchfork-shaped dermal denticles. It is ovoviviparous with probably around 12 pups per litter. It is taken by deepwater longline fisheries off Madeira and the Canary Islands for its meat and liver oil and as bycatch by bottom trawl fisheries elsewhere.