Acanthorhachis

Acanthorhachis; Temporal range: Visean– Westphalian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Order:	incertae sedis
Family:	†Listracanthidae
Genus:	†Acanthorhachis; Martill, Del Strother, & Gallien, 2013
Species:	†A. spinatus
Binomial name
	†Acanthorhachis spinatus; (Bolton, 1896) Martill, Del Strother, & Gallien, 2013

Acanthorhachis is an enigmatic extinct genus of chondrichthyan from the Carboniferous period.^[1] Its name is derived from the Greek word acanthos meaning "spine" and the Greek suffix for spine, -rhachis. This is due to the spine-like dermal denticles and their subsidiary spines, which coated the exterior of the animal. The authors who erected this genus suggested the common name "The Spiny Spined Shark." The type species Listracanthus spinatus was in 1896 named by Herbert Bolton.

It is closely related to Listracanthus. It differs from it in the size, structure, and distribution of dermal spines. It is currently monotypic, containing only the species A. spinatus. This shark is thus far only described from the British Isles. Acanthorhachis was first described from the Westphalian-aged lower coal measures of Yorkshire, England.^[2] It occurs rarely in Viséan-aged Eyam Limestone of Derbyshire, England.^[3]

References

^ "Fossilworks: Acanthorhachis". fossilworks.org. Retrieved 17 December 2021.
^ MARTILL, DAVID M.; DEL STROTHER, PETER J. A.; GALLIEN, FLORENCE (2013-07-08). "Acanthorhachis, a new genus of shark from the Carboniferous (Westphalian) of Yorkshire, England". Geological Magazine. 151 (3): 517–533. doi:10.1017/s0016756813000447. ISSN 0016-7568. S2CID 129437036.
^ Smith, Roy; Martill, David M.; Duffin, Christopher (2017-06-01). "The shark-beds of the Eyam Limestone Formation (Lower Carboniferous, Viséan) of Steeplehouse Quarry, Wirksworth, Derbyshire, UK". Proceedings of the Geologists' Association. 128 (3): 374–400. doi:10.1016/j.pgeola.2017.04.004. ISSN 0016-7878.

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[1] "Fossilworks: Acanthorhachis". fossilworks.org. Retrieved 17 December 2021.

[2] MARTILL, DAVID M.; DEL STROTHER, PETER J. A.; GALLIEN, FLORENCE (2013-07-08). "Acanthorhachis, a new genus of shark from the Carboniferous (Westphalian) of Yorkshire, England". Geological Magazine. 151 (3): 517–533. doi:10.1017/s0016756813000447. ISSN 0016-7568. S2CID 129437036.

[3] Smith, Roy; Martill, David M.; Duffin, Christopher (2017-06-01). "The shark-beds of the Eyam Limestone Formation (Lower Carboniferous, Viséan) of Steeplehouse Quarry, Wirksworth, Derbyshire, UK". Proceedings of the Geologists' Association. 128 (3): 374–400. doi:10.1016/j.pgeola.2017.04.004. ISSN 0016-7878.

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