Narrownose chimaera
Species of cartilaginous fish
From Wikipedia, the free encyclopedia
The narrownose chimaera (Harriotta raleighana) is a longnose chimaera of the family Rhinochimaeridae,[3] the longnose chimaeras, consisting of eight species belonging three genera.[4] This species is found in temperate seas worldwide, at depths between 200 and 3,100 m.[3] Its length is between 1.0 and 1.5 m, including a long, tapering snout and a long, filamentous tail.[5]
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| Narrownose chimaera | |
|---|---|
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Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Holocephali |
| Order: | Chimaeriformes |
| Family: | Rhinochimaeridae |
| Genus: | Harriotta |
| Species: | H. raleighana |
| Binomial name | |
| Harriotta raleighana | |
Taxonomy
This species was first described by George Brown Goode and Tarleton Hoffman Bean in 1895.[2] The genus Harriotta refers to Thomas Harriot and the species name references Sir Walter Raleigh.[3][2]
Description
Narrownose chimaeras have elongate rostra, slender tails, large pectoral and pelvic fins, large eyes, and two dorsal fins, the first being preceded by a mildly toxic spine.[4][2] The spine of their first dorsal fin extends beyond the tip of the fin, and is slightly curved.[6] They possess two pairs of non-replaceable tooth plates in the upper jaw and one pair in the lower jaw.[7] Male H. raleighana are estimated to reach 62.8 cm (24.7 in) and female 75.8 cm (29.8 in) at maturity, respectively.[8] The maximum total length of H. raleighana is approximately 120 centimetres (47 in), and at birth they have a precaudal length of 10–13 centimetres (3.9–5.1 in).[6]
Habitat
The narrownose chimaera is found off Nova Scotia and in much of the rest of the Atlantic Ocean,[9] and in parts of the Pacific Ocean to depths of 3100 metres.[4] Very little is known of their biology due to their deep water habitats.[7] They have been found at depths of 200–3,100 metres (660–10,170 ft), although mostly deeper than 500m, and there is a suspected ontogenetic shift between 200–1,000 metres (660–3,280 ft), with larger specimens living deeper than 1000m.[6]
Reproduction
Longnose chimaeras are members of the class Chondrichthyes, diverging from their closest relatives (sharks, rays, and skates) approximately 400 million years ago.[10] Like many other Chondrichthyes, longnose chimaeras reproduce by laying eggs.[8] Egg cases consist of a central chamber surrounded by a web-like structure[7] and are approximately 16mm long.[6] Female longnose chimaeras lay a pair of eggs several times per season.[10]
Conservation status
The IUCN has classified this species as being of least concern.[1] In June 2018 the New Zealand Department of Conservation classified the narrownose chimaera as "Not Threatened" under the New Zealand Threat Classification System.[11]