The Frilled shark, Chlamydoselachus anguineus, is a primitive shark species, of the family Chlamydoselachidae in the order Hexanchiformes. The Southern African frilled shark is a proposed new species from the Southern African range. These two species are very different from the other hexanchiform sharks, and it has recently been proposed that the two frilled sharks should be given their own order: Chlamydoselachiformes. Additional extinct types are known from fossil teeth; thought to be extinct itself, it was only discovered in Japanese waters in the 19th century. On January 21, 2007 a specimen was found alive off the coast of Japan near the Awashima Marine Park in Shizuoka, southwest of Tokyo. The shark was captured but died shortly afterwards.
Superficially, the frilled shark resembles a dark brown or grey eel, but the six gill slits identify it as a shark. The tissue of the gill slits protrudes somewhat, thus inspiring the common name. Its dorsal fin is small, anal fin large, and the caudal fin (tail fin) is highly asymmetric, the dorsal part almost unnoticeable. Its teeth are small, tricuspid, and very sharp. It has been recorded at up to 78.74 in (2 m) in length.
Distribution is worldwide, but they are very rarely found in shallow water. The sharks are usually found at depths of between 164.04 and 4921.26 ft (50 m and 1,500) m. They typically eat squid, other sharks, and deepwater bony fish.
Reproduction is not well understood, but like many other sharks they bear live young (ovoviviparous), with litter sizes of 2 to 12 pups. Compagno states “They are pregnant for a long time, probably one to two years”.
Frilled sharks appear regularly in the catches from bottom trawling, and when caught are used as food or for fishmeal.
On January 21, 2007, the staff at Awashima Marine Park in Shizuoka, southwest of Tokyo, was alerted by fishermen to a ‘strange eel-like fish with razor sharp teeth’. The fish was identified as a female 1.6 m frilled shark and was captured by park staff who were concerned that the shark appeared to be unhealthy. They took it out of the water and put it into a salt water tank where they filmed it and took pictures of it. The shark died a few hours after capture. This rare surface appearance of a frilled shark has been attributed to the animal being unwell and possibly disoriented.