Sailfin roughshark
| Sailfin roughshark | |
|---|---|
| |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Subdivision: | Selachimorpha |
| Order: | Squaliformes |
| Family: | Oxynotidae |
| Genus: | Oxynotus |
| Species: | O. paradoxus
|
| Binomial name | |
| Oxynotus paradoxus Frade,1929
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| Range of the sailfin roughshark | |
Thesailfin roughshark(Oxynotus paradoxus) is aspeciesofdogfish sharkin thefamilyOxynotidae,found in the easternNorth AtlanticfromScotlandtoSenegalbetweenlatitudes61°Nand11°N,at depths of between 265 and 720 m (869 and 2,362 ft). Its length is up to 1.2 m (3.9 ft).
Its reproduction isovoviviparous.
Oxynotus paradoxusis thought to be a slow-moving predator of smallbenthic animals.The sailfin roughsharks is found near the EasternAtlantic Oceanat those depths. However, it has been reported to be found on the shores ofMorocco,recently reported in theMid-Atlantic Ridge,and in theAzoreswater. This species is an uncommonbycatchof bottom trawls, and is listed by theInternational Union for Conservation of Nature(IUCN) as Vulnerable.[2]
Taxonomy
[edit]French biologist F. Frade found this species ofOxynotus paradoxus.This name was later finalized and accepted by the scientific community as the official name for the species. Frade published his findings of this specimen in 1929 in the scientific journalBoletim da Sociedade Portuguesa de Ciências Naturais.[3]
Description
[edit]Oxynotus paradoxusis a rare shark found in the deep waters of the ocean from about 265–750 m below ocean level. At birth,O. paradoxusis about 25 cm in length and can grow up to 118 cm in length.[2]It has a compressed body form with a blunt snout and a wide, flattened head.O. paradoxushas two tall, narrow and pointeddorsal finsthat contain concave trailing edges, but noanal fin.The first dorsal spine trails back, a unique feature of this species ofOxynotus.Bothspiraclesare relatively small compared to other sharks and are almost completely circular. The top teeth ofO. paradoxusarelanceolate,but the lower teeth are blade-like. Each set of both upper and lower teeth contain 12 rows of teeth.[4]The flankdermal denticlescontain a central cusp next to two lateral cusps and a second middle cusp above the primary cusp.[5]
Of all the AtlanticOxynotusspecies,O. paradoxusis the only species to have an incline firstdorsal finspine. The color of the shark when living is uniform dark brown, but it turns black in preserved specimens.[5]
Reproduction
[edit]This species of shark is an ovoviviparous species, meaning the embryos develop inside eggs, which are retained inside the mother's body until the eggs are ready to hatch. These shark pups are about 25 cm in length.[4]
Geographical habitat and ecology
[edit]Oxynotus paradoxuslives in two separate places: the NortheastAtlanticand Easter Central Atlantic. In the Northeast Atlantic they are found along the Atlantic slope of Scotland and theMid-Atlantic ridge.In the Eastern Central Atlantic they are found from Morocco southward to theGulf of Guinea.[4]
Based on the distribution ofO. paradoxus,occupying a bathybenthic habitat, the species can be classified as abenthosorganism with reproductive migrations to the continental shelf in spring.[4]
O. paradoxusis found in the depths of 265–800 m below sea level. Due to their poor ability to swim, they use their relatively large and oil-filled livers to maintain their buoyancy.[4]
Diet
[edit]The diet ofO. paradoxusis largely unknown; however, from reported sightings of the shark, it has been identified that they feast on smallbenthic fishandinvertebrates.[4]
Threat and conservation
[edit]Since this species lives in the depths where deepwater fisheries operate, they can have a negative impact on the already uncommon species by being the bycatch of these offshore fisheries. Although their population is unknown, most of its population is in the deeper offshore waters and very few are in the inshore waters.[4]
Although this shark is a bycatch by offshore fisheries, it has little to no commercial uses. When caught, the most probable use ofO. paradoxusis as fishmeal or bait.[4]
References
[edit]- ^Finucci, B., Derrick, D. & VanderWright, W.J. (2020)."Oxynotus paradoxus".IUCN Red List of Threatened Species.2020:e.T161361A124471790.doi:10.2305/IUCN.UK.2021-2.RLTS.T161361A124471790.en.Retrieved7 October2021.
{{cite journal}}:CS1 maint: multiple names: authors list (link) - ^abFinucci, B.; Derrick, D.; VanderWright, W.J. (2021)."Oxynotus paradoxus".IUCN Red List of Threatened Species.2021:e.T161361A124471790.doi:10.2305/IUCN.UK.2021-2.RLTS.T161361A124471790.en.Retrieved12 November2021.
- ^FrAde F., 1929. “Une nouvelle espèce ou une aberration individuelle de l’Oxynotus centrina” (Linn.). Bull. Soc. Port. Sci. Nat., 10(22): 263-267.
- ^abcdefghHurst, Richard. "Factsheet: Sailfin Roughshark." Factsheet: Sailfin Roughshark. 30 November 2013. <http:// sharktrust.org/en/factsheets/45/sailfin-roughshark.html>.
- ^abAzevedo, Jose, Fernando Sousa, and Joao Brium. "Dermal denticles and morphometrics of the sailfin roughshark Oxynotus paradoxus (elasmobranchii, oxynotidae), with comments on its geographic Distribution." Cybium 27 (2003): 117-122. <http:// mnhn.fr/sfi/cybium/numeros/pdf/272pdf/06-Azevedo%20109.pdf>.
- Froese, Rainer; Pauly, Daniel (eds.) (2006)."Oxynotus paradoxus"inFishBase.July 2006 version.