''Rolfodon'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

in the family

Chlamydoselachidae ''Chlamydoselachus'' is a genus of sharks and the sole extant member of the family Chlamydoselachidae, in the order Hexanchiformes. It contains two extant and several extinct species. The most widely known species still surviving is the frilled ...

. It is closely related to the extant frilled sharks in the genus ''

Chlamydoselachus ''Chlamydoselachus'' is a genus of sharks and the sole extant member of the family (biology), family Chlamydoselachidae, in the order (biology), order Hexanchiformes. It contains two extant and several extinct species. The most widely known speci ...

'', which it can be differentiated from by tooth morphology. It is named after late Canadian paleontologist Rolf Ludvigsen. The earliest fossil teeth of ''Rolfodon'' are known from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

( Campanian), and it is one of two genera of Chlamydoselachidae along with ''Chlamydoselachus'' known to have survived the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

, although unlike ''Chlamydoselachus'', ''Rolfodon'' went extinct by the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

. Remains are known from worldwide, including

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ...

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

, and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

. As with modern frilled sharks, ''Rolfodon'' appears to have been specialized to deep-water environments.

Species

The following species are known: * ''R. bracheri'' (Pfeil, 1983) – Early Miocene of Austria * ''R. fiedleri'' (Pfeil, 1983) – Eocene of Austria * ''R. goliath'' ( Antunes & Cappetta, 2002) – Late Cretaceous of Angola * ''R. keyesi'' (Mannering & Hiller 2008) – Early Paleocene of New Zealand * ''R. landinii'' (Carrillo-Briceño et al. 2014) – Late Miocene of Ecuador * ''R. ludvigseni'' Cappetta, Morrison & Adnet, 2019 – Late Cretaceous of Canada * ''R. tatere'' (Consoli, 2008) – Late Cretaceous to Early Paleocene of New Zealand and Antarctica * ''R. thomsoni'' (Richter & Ward, 1990) – Late Cretaceous of Antarctica The majority of these species were previously classified in ''Chlamydoselachus''. One species, ''Chlamydoselachus baumgartneri'', was moved to its own genus ''Proteothrinax'' in 2012. ''P. baumgartneri'' was later found to be conspecific with the previously described ''C. fiedleri'', but ''fiedleri'' was found to belong to ''Rolfodon'' by Cappeta ''et al'' (2019). ''R. goliath'', from the Late Campanian of Angola's southern Benguela Basin, could grow to very large sizes. It was described by Miguel Telles Antunes and Henri Cappetta in 2002 during the beginning stages of the PaleoAngola project. The holotype, MUS ANG 23, is rather large. This tooth is about 20mm high, and is characterised by straightened, upright cusps with smooth enameloid which lack ornamentation.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.
/ref> 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.

References

{{Taxonbar, from=Q115009812 Chlamydoselachidae Prehistoric shark genera Campanian genus first appearances Fossil taxa described in 2019 Messinian genus extinctions