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Longhead catshark

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Longhead catshark

Longhead catshark
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Carcharhiniformes
Family: Scyliorhinidae
Genus: Apristurus
Species: A. longicephalus
Binomial name
Apristurus longicephalus
Nakaya, 1975
Range of the longhead catshark

The longhead catshark or smoothbelly catshark (Apristurus longicephalus) is a IUCN currently lacks the data to assess the conservation status of this species.

Contents

  • Taxonomy and phylogeny 1
  • Distribution and habitat 2
  • Description 3
  • Biology and ecology 4
  • Human interactions 5
  • References 6

Taxonomy and phylogeny

The first known specimen of the longhead catshark was captured in Tosa Bay, Kochi Prefecture, Japan, on May 12, 1972.[2] The 38-cm-long specimen was initially thought to be an immature male, but has since been identified as a functionally female hermaphrodite.[3] The new species was described by Kazuhiro Nakaya in a 1975 volume of the scientific journal Memoirs of the Faculty of Fisheries, Hokkaido University.[2] In 1999, Nakaya and Sato grouped this species with the similarly long-snouted longfin catshark (A. herklotsi) in the A. longicephalus species group.[1]

Distribution and habitat

Records of the longhead catshark are patchy and widely spread in the Indo-Pacific region: it is known from the East China Sea, southern Japan, the Seychelles, the Philippines, Mozambique, New Caledonia, and northern Australia off Townsville, Ashmore Reef, and North West Cape.[4] This species inhabits the continental slope at depths of 500–1,140 m (1,640–3,740 ft), and is probably found near the sea floor.[1][5]

Description

Reaching a length of 59 cm (23 in), the longhead catshark has a soft, very thin body and a long head comprising one-quarter of its total length. The flattened, bell-shaped snout measures roughly 12% of the total length and narrows considerably in front of the nostrils. The oblique nostrils are divided into large, oval incurrent and excurrent openings by triangular flaps of skin on their anterior rims. The small, horizontally oval eyes are somewhat upward-facing, and equipped with rudimentary nictitating membranes. Behind each eye is a modest spiracle. The mouth forms a short, wide arch, with well-developed furrows around the corners.[2][5] The teeth number 36–44 rows in the upper jaw and over 45 rows in either jaw; each tooth is well-spaced from the next and has three or five cusps, with the central cusp much longer than the others.[4][6] The five pairs of gill slits are short, with the fourth and fifth pairs over the base of the pectoral fins.[2]

The first dorsal fin has a rounded apex and located over the latter third of the pelvic fin bases. The second dorsal fin is similar in shape but much larger than the first, and located over the latter half of the anal fin base. The pectoral fins are moderately large and broad. The medium-sized, rounded pelvic fins are placed fairly close to the pectoral fins. The anal fin is elongated and angular, and separated from the caudal fin by only a deep notch. The narrow caudal fin comprises about one-third of the total length and has a distinct lower lobe and a ventral notch near the tip of the upper lobe. The tiny, well-spaced dermal denticles, each bearing a median ridge and three posterior points, give the skin a velvety texture. A large patch of naked skin extends from the throat and gill region, around the pectoral fins and over the flank and abdomen, to the space between the pelvic and anal fins. Denticles are also absent near the fin margins. This species is dark brown to blackish in color; the naked patches of skin and the interior of the mouth are black.[2][4][5]

Biology and ecology

The longhead catshark is unique among Apristurus species in that the [3] The factors underlying the evolution of this system have yet to be investigated.[3] This species is oviparous; a single partial egg case has been found, which had tendrils on the posterior corners.[7] Males and females attain sexual maturity at lengths of around 42–49 cm (17–19 in) and 51 cm (20 in) long respectively.[1][4]

Human interactions

The longhead catshark is caught incidentally by deep-water trawl fisheries, though no specific information is available. Thus, the IUCN has listed it as Data Deficient.[1]

References

  1. ^ a b c d e Duffy, C. and C. Huveneers (2004). "Apristurus longicephalus".  
  2. ^ a b c d e Nakaya, K. (1975). "Taxonomy, comparative anatomy and phylogeny of Japanese catsharks, Scyliorhinidae". Memoirs of the Faculty of Fisheries, Hokkaido University 23: 1–94. 
  3. ^ a b c Iglésias, S. P.; Sellos, D. Y.; Nakaya, K. (2005). "Discovery of a normal hermaphroditic chondrichthyan species: Apristurus longicephalus". Journal of Fish Biology 66 (2): 417.  
  4. ^ a b c d Last, P.R. and J.D. Stevens (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. p. 191.  
  5. ^ a b c Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Food and Agricultural Organization. p. 271.  
  6. ^ a b Nakaya, K. (December 13, 1991). "A Review of the Long-Snouted Species of Apristurus (Chondrichthyes, Scyliorhinidae)". Copeia 1991 (4): 992–1002.  
  7. ^ Flammang, B.; Ebert, D.; Cailliet, G. (2007). "Egg cases of the genus Apristurus (Chondrichthyes: Scyliorhinidae): phylogenetic and ecological implications". Zoology (Jena, Germany) 110 (4): 308–317.  
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