Rolfodon

Rolfodon
Temporal range: Santonian–Early Pliocene
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Hexanchiformes
Family: Chlamydoselachidae
Genus: †Rolfodon
Cappetta, Morrison & Adnet, 2019
Species

See text

Synonyms
  • Thrinax Pfeil, 1983 non Thrinax Konow, 1885
  • Proteothrinax Pfeil, 2012

Rolfodon is an extinct genus of shark in the family Chlamydoselachidae. It is closely related to the extant frilled sharks in the genus Chlamydoselachus, which it can be differentiated from by tooth morphology. It is named after late Canadian paleontologist Rolf Ludvigsen.[1]

The earliest fossil teeth of Rolfodon are known from the Late Cretaceous (Turonian/Santonian boundary) of Japan, and it is one of two genera of Chlamydoselachidae along with Chlamydoselachus known to have survived the Cretaceous–Paleogene extinction event, although unlike Chlamydoselachus, Rolfodon went extinct by the Early Pliocene. Remains are known from worldwide, including Japan, Canada, Austria, New Zealand, Angola, Ecuador, and Antarctica. As with modern frilled sharks, Rolfodon appears to have been specialized to deep-water environments.[1][2]

Species

The following species are known:[1][2][3]

  • R. bracheri (Pfeil, 1983) – Early Miocene (Aquitanian to Burdigalian) of Austria, Germany & Japan
  • R. fiedleri (Pfeil, 1983) – Late Eocene (Bartonian) of Austria
  • R. goliath (Antunes & Cappetta, 2002) – Late Cretaceous (Campanian) of Angola
  • R. keyesi (Mannering & Hiller 2008) – Early Paleocene of New Zealand
  • R. landinii (Carrillo-Briceño et al. 2014) – Middle Miocene (Langhian to Serravallian) of Ecuador
  • R. ludvigseni Cappetta, Morrison & Adnet, 2019 – Campanian of British Columbia, Canada (Northumberland Formation)
  • R. tatere (Consoli, 2008) – Late Cretaceous (Maastrichtian) to Early Paleocene of New Zealand and Antarctica
  • R. thomsoni (Richter & Ward, 1990) – Maastrichtian of Antarctica

The majority of these species were previously classified in Chlamydoselachus.[1] One species, Chlamydoselachus baumgartneri, was moved to its own genus Proteothrinax in 2012.[4] P. baumgartneri was later found to be conspecific with the previously described C. fiedleri[5], but fiedleri was found to belong to Rolfodon by Cappeta et al (2019).[1]

In addition to the genus as a whole, one individual species is also known to have survived the Cretaceous-Paleogene extinction event: R. tatere, which was first described from the Early Paleocene of New Zealand and was later also identified from the Late Cretaceous of Antarctica, extending the record of its existence by over 10 million years.[1][3]

R. bracheri from the Early Miocene was one of the most widespread species, with fossil teeth known from the European Paratethys and from Japan. The last records of Rolfodon are indeterminate teeth from the Early Pliocene of Japan.[2]

R. goliath, from the Late Campanian of Angola's southern Benguela Basin, could grow to very large sizes.[6] It was described by Miguel Telles Antunes and Henri Cappetta in 2002 during the beginning stages of the PaleoAngola project.[7] The holotype, MUS ANG 23, is rather large. This tooth is about 20mm high,[8] and is characterised by straightened, upright cusps with smooth enameloid which lack ornamentation.[9]

References

  1. ^ a b c d e f 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.
  2. ^ a b c 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. Bibcode:2024PalJ...58..567M. doi:10.1134/S0031030124600665. ISSN 1555-6174.
  3. ^ a b dos Santos, Rodolfo Otávio; Riff, Douglas; Amenábar, Cecilia R.; Ramos, Renato Rodriguez Cabral; Rodrigues, Igor Fernandes; Scheffler, Sandro Marcelo; Carvalho, Marcelo de Araújo (2022-11-14). "New records of hexanchiform sharks (Elasmobranchii: Neoselachii) from the Late Cretaceous of Antarctica with comments on previous reports and described taxa". New Zealand Journal of Geology and Geophysics. 67 (2): 163–178. doi:10.1080/00288306.2022.2143382. ISSN 0028-8306.
  4. ^ Friedrich H. Pfeil (2012). "Proteothrinax, a new replacement name for Thrinax Pfeil, 1983 (Elasmobranchii: Chlamydoselachidae)" (PDF). In Friedrich H. Pfeil (ed.). Piscium Catalogus: Elasmobranchii, Pars 1 – Proteothrinax nom. nov. Verlag Dr. Friedrich Pfeil. p. 1. ISSN 0724-9012. {{cite book}}: |journal= ignored (help)
  5. ^ Richter, Martha; David J. Ward (March 1990). "Fish remains from the Santa Marta Formation (Late Cretaceous) of James Ross Island Antarctica". Antarctic Science. 2 (1): 67–76. Bibcode:1990AntSc...2...67R. doi:10.1017/S0954102090000074. S2CID 140650195. no
  6. ^ "Rolfodon goliath (Antunes & Cappetta, 2002)". Shark references.
  7. ^ Henri Cappetta; Kurt Morrison; Sylvain Adnet (2019). "A shark fauna from the Campanian of Hornby Island, British Columbia, Canada: an insight into the diversity of Cretaceous deep-water assemblages". Historical Biology: An International Journal of Paleobiology. 33 (8): 1121–1182. doi:10.1080/08912963.2019.1681421.
  8. ^ Cappetta et al. (2016) "New selachian assemblages from the Oligocene of Moravia (Czech Republic)", Researchgate
  9. ^ Carlsen, A.W. & Cuny, G. 2014. A study of the sharks and rays from the Lillebælt Clay (Early–Middle Eocene) of Denmark, and their palaeoecology. © 2014 by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 39–88. ISSN 2245-7070.