Velvet dogfish

Velvet dogfish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Division: Selachii
Order: Squaliformes
Family: Somniosidae
Genus: Zameus
D. S. Jordan & Fowler, 1903
Species:
Z. squamulosus
Binomial name
Zameus squamulosus
(Günther, 1877)
Range of the velvet dogfish
Synonyms
  • Centrophorus squamulosus Günther, 1877
  • Scymnodon obscurus Vaillant, 1888
  • Scymnodon niger Chu & Meng, 1982
  • Scymnodon squamulosus Günther, 1877

The velvet dogfish (Zameus squamulosus), the only member of the genus Zameus, is a small sleeper shark of the family Somniosidae, found around the world between latitudes 64°N and 48°S, from the surface to 2,000 m.[2]

Description

Velvet dogfish range from 24.5 cm up to 84 cm.[3][4] Although sharks within the family Somniosidae have generally been accepted to be non-luminous, Zameus squamulosus has photophores on its ventral epidermis allowing for them to be bioluminescent.[3][5] They are mainly found as common bycatch to commercial fishes such as scabbardfish, tuna and swordfish.[4][6] Despite being common bycatch, little is known of their biology to them inhabiting deeper waters which are difficult to access.

Distribution

Zameus squamulosus is found in latitudes between 64°N and 48°S within the Atlantic, Pacific and Indian Ocean.[4] One well documented area of Zameus squamulosus is within the cost of Hawaii during fishing as it is common bycatch to tuna and swordfish.[4] However they are commonly described as bottom dwelling fishes off continental and insular slopes within depths up to 2000 meters deep.[7][8][9] Due to it inhabiting deeper waters, it is not well known just how far Zameus squamulosus is distributed.

Biology

There is debate as to how the Velvet dogfish reproduces. One belief is that they reproduce ovoviviparously.[3] Ovoviviparous is a form of life birth in which the eggs are “hatched” and the offspring grows within the female before being delivered. However, it is also believed that they actually reproduce viviparously, having a litter of 3 to 10 pups throughout the year. It is not assumed to have any breeding season.[10] Female maturity in Zameus squamulosus is undetermined and varies widely throughout studies. It is estimated to be reached once they are about 71.5cm size in total length, with a maximum length of about 73cm for pregnant females for some, but there are records of mature females being as small as 57.1cm.[4][6]  Male maturity is believed to range from 493mm to 950mm with some males being measured as small as 410mm.[4][6] It is inferred that they feed primarily on squid. Velvet dogfish primarily feed on squid which are abundant in their deep habitat, where other prey such as crustaceans and shrimp are less common.[4] There is also the belief that Zameus squamulosus take advantage of the migration current of squid and fish to enhance their predation success.[4]  While a majority of Squaliformes possess “bristle and spine-shaped” placoid scales, Zameus squamulosus do not.[5] Rather, their scales overlap and possess of a role as a “bioluminescence enhancer”.[5] The inferred purpose of these bioluminescent placoid scales is to prevent predation from predators underneath them as it emits blue-green light.[10]

Conservation

The main interaction with Zameus squamulosus with humans is through being bycatch within the fishing industry, despite mainly inhabiting deeper waters.[4][6] In June 2018 the New Zealand Department of Conservation classified the velvet dogfish as "Data Deficient" with the qualifier "Uncertain whether Secure Overseas" under the New Zealand Threat Classification System.[11]

References

Wikimedia Commons has media related to Velvet dogfish.
  1. ^ Finucci, B.; Cheok, J.; Cotton, C.F.; Kulka, D.W.; Neat, F.C.; Pacoureau, N.; Rigby, C.L.; Tanaka, S.; Walker, T.I. (2020). "Zameus squamulosus". IUCN Red List of Threatened Species. 2020 e.T60215A3093577. doi:10.2305/IUCN.UK.2020-3.RLTS.T60215A3093577.en. Retrieved 18 November 2021.
  2. ^ White, William T.; Last, Peter R. (2013-12-24). "Notes on shark and ray types at the South China Sea Fisheries Research Institute (SCSFRI) in Guangzhou, China". Zootaxa. 3752 (1): 228–248. doi:10.11646/zootaxa.3752.1.14. ISSN 1175-5334.
  3. ^ a b c Straube, N.; Chenhong, L.; Claes, J.M.; Corrigan, S.; Naylor, G.J.P. (2015). "Molecular phylogeny of squaliforms and first occurrence of bioluminescence in sharks". Evolutionary Biology. 15 (1): 162. Bibcode:2015BMCEE..15..162S. doi:10.1186/s12862-015-0446-6. PMC 4537554. PMID 26277575.
  4. ^ a b c d e f g h i "Vertical distribution, diet, and reproduction of the velvet dogfish (Zameus squamulosus) in waters off Hawaii | Scientific Publications Office". spo.nmfs.noaa.gov. Retrieved 2025-11-15.
  5. ^ a b c Lourtie, Alexia; Duchatelet, Laurent; Straube, Nicolas; Puozzo, Nathan; Grace, Mark A.; Naylor, Gavin J. P.; Delroisse, Jérôme (2022-09-15). "Placoid scales in bioluminescent sharks: Scaling their evolution using morphology and elemental composition". Frontiers in Marine Science. 9 908237. Bibcode:2022FrMaS...908237L. doi:10.3389/fmars.2022.908237. hdl:2078.1/268472. ISSN 2296-7745.
  6. ^ a b c d Pajuelo, José G.; González, José A.; Santana, José I. (2010-12-01). "Bycatch and incidental catch of the black scabbardfish (Aphanopus spp.) fishery off the Canary Islands". Fisheries Research. 106 (3): 448–453. Bibcode:2010FishR.106..448P. doi:10.1016/j.fishres.2010.09.019. ISSN 0165-7836.
  7. ^ Villalobos, Eduardo; Martinez, Armando; Lambarri, Christian; Espinosa, Hector (2016). "New record of Zameus squamulosus (Chondrichthyes: Squaliformes: Somniosidae) in the Southern Gulf of Mexico". Marine Biodiversity Records. 9 (1) 61. Bibcode:2016MBdR....9...61V. doi:10.1186/s41200-016-0047-0. ProQuest 2047942467.
  8. ^ Ebert, Davis; Knuckey, James; Kamikawa, Daniel (2014). "First eastern North Pacific record of the velvet dogfish, Zameus squamulosus (Chondrichthyes: Squaliformes: Somniosidae)". Marine Biodiversity Records. 7 e48. Bibcode:2014MBdR....7E..48E. doi:10.1017/S1755267214000499. ProQuest 1644675020.
  9. ^ Triay-Portella, Raül; González, José A.; Lorenzo, José M.; Pajuelo, José G. (2023-04-01). "Structure and composition of the deep-sea fish community between 150 and 2050 m depth on the Canary Islands, eastern-central Atlantic". Deep Sea Research Part I: Oceanographic Research Papers. 194 103966. Bibcode:2023DSRI..19403966T. doi:10.1016/j.dsr.2023.103966. ISSN 0967-0637.
  10. ^ a b Duchatelet, Laurent; Marion, Raphaël; Mallefet, Jérôme (2021). "A Third Luminous Shark Family: Confirmation of Luminescence Ability for Zameus squamulosus (Squaliformes; Somniosidae)". Photochemistry and Photobiology. 97 (4): 739–744. doi:10.1111/php.13393. hdl:2078.1/244141. ISSN 1751-1097. PMID 33529364.
  11. ^ Duffy, Clinton A. J.; Francis, Malcolm; Dunn, M. R.; Finucci, Brit; Ford, Richard; Hitchmough, Rod; Rolfe, Jeremy (2018). Conservation status of New Zealand chondrichthyans (chimaeras, sharks and rays), 2016 (PDF). Wellington, New Zealand: Department of Conservation. p. 11. ISBN 978-1-988514-62-8. OCLC 1042901090.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.