Extinct genus of shark
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.
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.
Species.
The following species are known:
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).
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.
"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.
"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.
References.
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