Jensen's skate
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Rajiformes
Family: Rajidae
Genus: Amblyraja
Species:
A. jenseni
Binomial name
Amblyraja jenseni
(Bigelow & Schroeder, 1950)
Synonyms
  • Raja jenseni

Jensen's skate (Amblyraja jenseni), also known as the shortail skate,[2] is a poorly known species of fish discovered in 2004 during a study of bottom ichthyofauna aboard the Norwegian RV G.O. Sars, where four species were identified, including A. jenseni.

Etymology

The skate is named in honor of Danish zoologist Adolf Severin Jensen (1866–1953), of Lund University, for his contributions to the ichthyology of the North Atlantic Ocean.[3]

Taxonomy

The shortail skate is a member of the family Rajidae, of which 30 genera and over 180 species are recognized. Amblyraja is the genus name of which 10 species are recognized, including A. doellojuradoi (southern thorny skate), A. frerichsi (thickbody skate), A. robertsi (bigmouth skate), etc.[2]

Description

Members of the family Rajidae carry uncharacteristically similar body plans. This makes visual identification of these individuals extremely difficult. Detailed visual descriptions of A. jenseni are hard to attain, so the description below may represent several of the family Rajidae and should not necessarily be used to differentiate them. A. jenseni is a medium-sized skate. Its maximum known length is 74.3 cm (29.3 in) for males and 85 cm (33 in) for females.[2] Its coloration is chocolate-brown to gray-brown above with scattered darker spots. Ventral on the body appears a patchy white and brown mixture, except for the pelvic fin lobes and tail, which are darker. These white patches are on the snout, upper abdomen, nostrils, mouth gill slits, and anal opening. Its underside is smooth and its dorsal surface is densely covered with prickly scales. Two or three pairs of distinctive scapular thorns are on each shoulder, usually arranged in a triangle, and a row of 24-29 median thorns occur along the back, flanked by a row of smaller lateral thorns on the tail. The tail of the shorttail skate is relatively short.[2] Sexual dimorphism in shorttail skates is present in pelvic fin structure that the males modify to act as copulatory claspers, as well as alternate disc lengths, horizontal diameter of the orbit, height of the tail at the pelvic fin tips, length of the third gill slit, and distances from the center of the anus to the first and second dorsal fins.[2]

Distribution and habitat

This species of skate is believed to only be found in the North Atlantic, off the coasts of New England, Nova Scotia, Grand Banks of Newfoundland, Iceland, Ireland, Canada, and along the Mid-Atlantic Ridge at depths of 167 to 2,548 m (548 to 8,360 ft),[2] making it one of the deepest-occurring skates known.

Biology and ecology

Skates represent a critical consumer of invertebrates and small fish, representing a similar role as apex predators of the ecosystem. Little is documented about their feeding behavior, but like other of its family, it presumably would eat various cephalopods, crustaceans, and small bony fish such as rattails and teleost fishers.[2] A. jenseni is presumed to be oviparous like other skates. but no observed reproduction cycles have been reported.[2]

References

  1. ↑ Kulka, D.W.; Cotton, C.F.; Anderson, B.; Herman, K.; Pacoureau, N. & Dulvy, N.K. (2020). "Amblyraja jenseni". IUCN Red List of Threatened Species. 2020: e.T161491A124494959. doi:10.2305/IUCN.UK.2020-3.RLTS.T161491A124494959.en. Retrieved 16 August 2023.
  2. 1 2 3 4 5 6 7 8 Orlov, Alexie M, et al. “Deepwater Skates (Rajidae) Collected during the 2004 Cruises of R.V. ‘G.O. Sars’ and ‘M.S. Loran’ in the Mid-Atlantic Ridge Area.” ResearchGate, Jan 2006
  3. ↑ "Family RAJIDAE Blainville 1816 (Skates)". etyfish.org.

Further reading


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