Paraorthacodus
| Paraorthacodus Temporal range:
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|---|---|
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| Paraorthacodus jurensis holotype specimen | |
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| Paraorthacodus jurensis full-body specimen | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Family: | †Paraorthacodontidae |
| Genus: | †Paraorthacodus Glückman, 1957 |
| Species | |
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P. andersoni | |
Paraorthacodus is an extinct genus of shark. It a member of the family Paraorthacodontidae[1][2] (though it was formerly regarded as a member of the family Palaeospinacidae[3]), which is either placed in Hexanchiformes[2] or in Synechodontiformes.[1] It is known from over a dozen named species[4] spanning from the Early Jurassic[4] to the Paleocene,[4] or possibly Eocene.[3] Almost all members of the genus are exclusively known from isolated teeth, with the exception of P. jurensis from the Late Jurassic-Early Cretaceous of Europe, which is known from full body fossils from the Late Jurassic of Germany,[5] which suggest that juveniles had a robust body with a round head, while adults had large body sizes with a fusiform profile.[1] There was only a single dorsal fin towards the back of the body without a fin spine.[3] The dentition had teeth with a single large central cusp along with shorter lateral cusplets,[3] which were designed for clutching.[1] The teeth are distinguished from those of Synechodus by the lateral cusplets decreasing in size linearly away from the central cusp rather than exponentially as in Synechodus.[3]
Taxonomy
[edit]- Paraorthacodus andersoni (Case, 1978) Late Cretaceous (Santonian and Campanian)
- Paraorthacodus antarcticus Klug et al., 2008 Late Cretaceous (Campanian)
- Paraorthacodus clarkii (Eastman, 1901) Paleocene (Thanetian)
- Paraorthacodus conicus (Davis, 1890) Late Cretaceous (Coniacian to Campanian)
- Paraorthacodus eocaenus (Leriche, 1902) Paleogene (Thanetian to Ypresian according to,[3] exclusively Thanetian according to,[4] considered a synonym of P. clarkii by[6])
- Paraorthacodus jurensis (Schweizer, 1964) Late Jurassic (Kimmeridgian)
- Paraorthacodus nerviensis (Leriche, 1929) uppermost Cretaceous
- Paraorthacodus patagonicus (Ameghino, 1893) Late Cretaceous (Coniacian)
- Paraorthacodus recurvus (Trautschold, 1877) Cretaceous (Albian-uppermost Cretaceous)
- Paraorthacodus sulcatus (Davis, 1888) Late Cretaceous (Campanian)
- Paraorthacodus validus (Chapman, 1918) from the Cretaceous
- Paraorthacodus turgaicus Glickman, 1964, Paleocene (Thanetian)
- Paraorthacodus helveticus (De Beaumont 1960) Early Jurassic (Sinemurian)
- Paraorthacodus arduennae Delsate, 2001) Early Jurassic (Pliensbachian)
- Paraorthacodus kruckowi (Thies 1983) Middle Jurassic (Aalenian)
References
[edit]- ^ a b c d Villalobos-Segura, Eduardo; Stumpf, Sebastian; Türtscher, Julia; Jambura, Patrick L.; Begat, Arnaud; López-Romero, Faviel A.; Fischer, Jan; Kriwet, Jürgen (March 2023). "A Synoptic Review of the Cartilaginous Fishes (Chondrichthyes: Holocephali, Elasmobranchii) from the Upper Jurassic Konservat-Lagerstätten of Southern Germany: Taxonomy, Diversity, and Faunal Relationships". Diversity. 15 (3): 386. doi:10.3390/d15030386. ISSN 1424-2818. PMC 7614348. PMID 36950327.
- ^ a b Cione, Alberto L.; Santillana, Sergio; Gouiric-Cavalli, Soledad; Acosta Hospitaleche, Carolina; Gelfo, Javier N.; López, Guillermo M.; Reguero, Marcelo (May 2018). "Before and after the K/Pg extinction in West Antarctica: New marine fish records from Marambio (Seymour) Island". Cretaceous Research. 85: 250–265. Bibcode:2018CrRes..85..250C. doi:10.1016/j.cretres.2018.01.004. hdl:11336/99687. S2CID 133767014.
- ^ a b c d e f g Klug, Stefanie; Kriwet, JüRgen; BöTtcher, Ronald; Schweigert, GüNter; Dietl, Gerd (September 2009). "Skeletal anatomy of the extinct shark Paraorthacodus jurensis (Chondrichthyes; Palaeospinacidae), with comments on synechodontiform and palaeospinacid monophyly". Zoological Journal of the Linnean Society. 157 (1): 107–134. doi:10.1111/j.1096-3642.2009.00534.x.
- ^ a b c d e Cappetta, Henri; Morrison, Kurt; Adnet, Sylvain (2021-08-03). "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. Bibcode:2021HBio...33.1121C. doi:10.1080/08912963.2019.1681421. ISSN 0891-2963. S2CID 212878837.
- ^ Stumpf, Sebastian; Kriwet, Jürgen (December 2019). "A new Pliensbachian elasmobranch (Vertebrata, Chondrichthyes) assemblage from Europe, and its contribution to the understanding of late Early Jurassic elasmobranch diversity and distributional patterns". PalZ. 93 (4): 637–658. Bibcode:2019PalZ...93..637S. doi:10.1007/s12542-019-00451-4. ISSN 0031-0220.
- ^ Rodríguez, Diego; Ward, David John; Quezada, Jorge Andrés (2023-06-07). "Paleontology and stratigraphic implications of a late Paleocene elasmobranch assemblage in Talcahuano, southcentral Chile". Andean Geology. 50 (2): 217. doi:10.5027/andgeoV50n2-3494. ISSN 0718-7106. S2CID 259771898.
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