|Scientific Name:||Apristurus longicephalus Nakaya, 1975|
|Taxonomic Notes:||The genus Apristurus contains at least 32 described species and a relatively large number of potentially undescribed ones. Morphological conservatism and, until recently, a lack of objectively defined characters makes this one of the most taxonomically confused shark genera (Compagno 1984, Nakaya and Sato 1999).
Nakaya and Sato (1999) defined three species groups within Apristurus: the longicephalus-group (two species), brunneus-group (20 species) and spongiceps-group (10 species). The longicephalus-group is characterized by a long, narrow snout (prenarial length > 6.4% TL). A. longicephalus is readily distinguished from A. herklotsi, the other member of the group, by a higher spiral valve count (13 to 17 c.f. 10 to 11 in A. herklotsi), a shorter snout (pre-oral length always < 12.2% TL c.f. >12.3% TL), and fewer tooth rows (36 to 44 and 31 to 41 rows upper and lower jaws c.f. 49 to 57 and 49 to 58 rows). A longicephalus is unique amongst the Apristurus species in having a duodenum almost as long as the valvular intestine. Both species have a continuous supraorbital sensory canal, and similar numbers of monospondylous vertebrae (Nakaya 1988a, 1988b, 1991, Nakaya and Sato 1999).
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Duffy, C.A.J. & Huveneers, C.|
|Reviewer(s):||Kyne, P.M. & Walls, R.H.L.|
|Contributor(s):||Kyne, P.M. & Walls, R.H.L.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Longhead Catshark (Apristurus longicephalus) is a relatively small species (up to at least 59 cm total length) with a patchy known distribution in the Indo-West Pacific including Japan, Taiwan, the Philippines, and northern Australia. It is recorded over the continental slope at depths of 500–1,140 m. Throughout its geographic range this catshark may be taken as bycatch in deepwater fisheries, though species-specific catch data are not available. Despite being a poorly-known species, it is wide-ranging and has refuge at depth at least where it occurs off Australia, and is therefore assessed as Least Concern.
|Previously published Red List assessments:|
|Range Description:||The Longhead Catshark has a patchy distribution in the Indo-West Pacific with records from Tosa Bay of Shikoku Island, southern Japan; Okinawa Trough, East China Sea; the Philippines; Taiwan; the Seychelles; Mozambique; off North West Cape and Ashmore Reef, Western Australia; off Townsville, north Queensland, Australia; and New Caledonia (Iglesias et al. 2005, Last and Stevens 2009, Ebert et al. 2013).|
Native:Australia (Queensland, Western Australia); China; Japan (Shikoku); Mozambique; New Caledonia; Philippines; Seychelles; Taiwan, Province of China
|FAO Marine Fishing Areas:|
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There is no information available on population size or structure.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Longhead Catshark occurs on or near the bottom of the continental slope at 500–1,140 m depth (Ebert et al. 2013). Males mature at 49 cm total length (TL), females at 51 cm TL, and the species reaches at least 59 cm TL (Last and Stevens 2009, Ebert et al. 2013). Male size at maturity is smaller than the other Japanese species (Longfin Catshark A. herklotsi, Flathead Catshark A. macrorhynchus, Spatulasnout Catshark A. platyrhynchus, and Japanese Catshark A. japonicus) suggesting it is a relatively small species (Nakaya 1988). Where known, reproduction of Apristurus species is oviparous with one egg per oviduct.|
|Use and Trade:||Not known to be utilized.|
|Major Threat(s):||Throughout its geographic range this species may be taken as bycatch in deepwater fisheries, though species-specific catch data are not available. Deepwater fisheries may expand in future, though the species is likely to be able to find refuge at depths outside their reach. In Australian waters there is limited fishery activity within its range.|
|Conservation Actions:||No conservation measures are currently in place for this species.|
|Citation:||Duffy, C.A.J. & Huveneers, C. 2015. Apristurus longicephalus. The IUCN Red List of Threatened Species 2015: e.T44217A68608927.Downloaded on 21 September 2017.|
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