Chlamydoselachus is a genus of sharks and the sole extant member of the family Chlamydoselachidae, in the order Hexanchiformes. It contains two extant and four extinct species. The most widely known species still surviving is the frilled shark (Chlamydoselachus anguineus). It is known as a living fossil, along with Chlamydoselachus africana, also known as the southern African frilled shark, which is only found along coastal areas of South Africa. The only two extant species of this genus are deep-sea creatures which are typically weakened in areas closer to the surface. While the two extant species are similar in external appearance, they differ internally.[2]
| Chlamydoselachus | |
|---|---|
| |
| Frilled shark (C. anguineus) | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Order: | Hexanchiformes |
| Family: | Chlamydoselachidae |
| Genus: | Chlamydoselachus Garman 1884 |
| Species | |
The earliest known fossil members of the genus are C. gracilis from Angola and C. balli from Canada, both from the Campanian stage of the Late Cretaceous. Formations with fossil Chlamydoselachus teeth are thought to be composed of deep-sea sediments, indicating that they have long inhabited deep-sea environments. Fossil Chlamydoselachus teeth closely resemble those of modern members.[3]
The largest species of the genus known to have existed is C. kamchaticus from the Early Eocene of Kamchatka, Russia, whose teeth are about twice the size of modern frilled shark teeth. It is one of the largest frilled sharks known to have existed, with estimated body length of 3.80 metres (12.5 ft).[4]
Species
edit- Chlamydoselachus africana Ebert & Compagno, 2009 (southern African frilled shark)
- Chlamydoselachus anguineus Garman, 1884 (frilled shark)
- †Chlamydoselachus balli Cappetta, Morrison & Adnet, 2019
- †Chlamydoselachus garmani Welton, 1983
- †Chlamydoselachus gracilis Antunes & Cappetta, 2002
- †Chlamydoselachus kamchaticus Malyshkina & Nazarkin, 2024[4]
- †Chlamydoselachus lawleyi Davis, 1887
- †Chlamydoselachus tobleri Leriche, 1929
Many other species formerly described in this genus were moved to the fossil genus Rolfodon in 2019. Chlamydoselachus and Rolfodon can be distinguished from one another by their tooth morphologies. Rolfodon also survived the Cretaceous-Paleogene extinction event but went extinct during the Miocene.[3]
References
edit- ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Chondrichthyes entry)". Bulletins of American Paleontology. 364: 560. Retrieved 2013-01-17.
- ^ Compagno, Leonard J. V.; Dando, Marc; Fowler, Sarah L.; Compagno, Leonard; Fowler, Sarah (2005). A field guide to the Sharks of the world. Collins field guide. London: Collins. ISBN 978-0-00-713610-0.
- ^ a b Cappetta, Henri; Morrison, Kurt; Adnet, Sylvain (2019-12-10). "A shark fauna from the Campanian of Hornby Island, British Columbia, Canada: an insight into the diversity of Cretaceous deep-water assemblages". Historical Biology. 33 (8): 1121–1182. doi:10.1080/08912963.2019.1681421. ISSN 0891-2963. S2CID 212878837.
- ^ a b Malyshkina, T. P.; Nazarkin, M. V. (2024-10-01). "Frilled Sharks (Hexanchiformes, Chlamydoselachidae): New Data on Their Diversity and Distribution". Paleontological Journal. 58 (5): 567–577. doi:10.1134/S0031030124600665. ISSN 1555-6174.
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