Squalodon

Name: Squalodon ‭(‬Shark tooth‭)‬.
Phonetic: Skwahl-o-don.
Named By: Jean-Pierre Sylvestre de Grateloup‭ ‬-‭ ‬1840.
Classification: Chordata,‭ ‬Mammalia,‭ ‬Cetacea,‭ ‬Platanistoidea,‭ ‬Squalodontidae.
Species: S.‭ ‬grateloupii‭ (‬type‭)‬,‭ ‬S.‭ ‬antverpiensis,‭ ‬S.‭ ‬atlanticus,‭ ‬S.‭ ‬barbarus,‭ ‬S.‭ ‬bariensis,‭ ‬S.‭ ‬bellunensis,‭ ‬S.‭ ‬bordae,‭ ‬S.‭ ‬calvertensis,‭ ‬S.‭ ‬catulli,‭ ‬S.‭ ‬dalpiazi,‭ ‬S.‭ ‬hypsispondylus,‭ ‬S.‭ ‬imperator,‭ ‬S.‭ ‬linzianus,‭ ‬S.‭ ‬melitensis,‭ ‬S.‭ ‬meyeri,‭ ‬S.‭ ‬molassicus,‭ ‬S.‭ ‬peregrinus,‭ ‬S.‭ ‬servatus,‭ ‬S.‭ ‬tiedemani,‭ ‬S.‭ ‬vocontiorum,‭ ‬S.‭ ‬whitmorei,‭ ‬S.‭ ‬wingei.
Diet: Carnivore.
Size: Uncertain,‭ ‬multiple species are named,‭ ‬but remains can be very fragmentary.
Known locations: Across Europe and North America,‭ ‬possibly also Japan.
Time period: Rupelian of the Oligocene through to Langhian of the Miocene.
Fossil representation: Multiple individuals,‭ ‬but often of very incomplete remains.





       Squalodon is the type genus of the Squalodontidae,‭ ‬a group of prehistoric whales that in‭ ‬evolutionary‭ ‬terms of are intermediary between the older Archaeoceti whales like Basilosaurus and Zygorhiza,‭ ‬and the later whales of the Odontoceti which includes modern toothed cetaceans like the killer whale‭ (‬Orcinus orca‭)‬.‭ ‬Exactly how Squalodon and the other relatives of the genus were related to modern cetaceans is still uncertain however due to many differing opinions.
       Squalodon is represented by numerous species,‭ ‬though there is sometimes question over which ones are valid because often Squalodon remains are only of teeth and jaw segments.‭ ‬Squalodon would have been predators of other marine organisms including fish and possibly other marine mammals.‭ ‬They also show an early development towards echolocation,‭ ‬but it is still unknown if they had the ability to echolocate prey themselves,‭ ‬or if that was a later development of Odontoceti whales.‭ ‬The broad geographic and temporal distribution of the genus however suggest that Squalodon were very successful.
       Although predators,‭ ‬themselves,‭ ‬Squalodon may not have been the top predators of the ocean during their time.‭ ‬Prehistoric sharks were growing to very large sizes during the time of Squalodon,‭ ‬and include such examples as C.‭ ‬angustidens,‭ ‬C.‭ ‬chubutensis to the fearsome and massive C.‭ ‬megalodon.‭ ‬The disappearance of Squalodon after the early Miocene also corresponds to a development of even more advanced predatory whales such as Brygmophyseter and Livyaten.

Further reading
- Notices of remains of extinct vertebrated animals of New Jersey, collected by Prof. Cook of the State Geological Survey under the direction of Dr. W. Kitchell. - Proceedings of the Academy of Natural Sciences of Philadelphia 8:220-221. - J. Leidy - 1856.
- Un mammifere nouveau du Ccrag d'Anvers. - Bulletins de L'Academie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique 12:22-28. - P. J. Van Beneden - 1861.
- Description de restes fossiles de deux grands mammifères constituant deux genres, l'un le genre Rhizoprion de l'ordre des Cétecés et du groupe des Delphinoides; l'autre le genre Dynocyon de l'ordre des Carnassiers et de la familie des Canidés. - Annales des Sciences Naturelles 16:369-374. - C. Jourdan - 1861.
- Alcuni resti di Squalodon dell'Arenaria Miocenica di Belluno. - Palaeontographia Italica 6:303-314. - G. Dal Piaz - 1901.
- Description of two squalodonts recently discovered in the Calvert Cliffs, Maryland; and notes on the shark-toothed cetaceans. - Proceedings of the U. S. National Museum 62(16):1-69. - R. Kellogg - 1923.
- The lower Serravallian cetacean fauna of Visiano (Northern Apennines, Parma, Italy). - Investigations on Cetacea 17:55-93. - F. Cigala-Fulgosi & G. Pilleri - 1985.
- A new species of Squalodon (Mammalia, Cetacea) from the Middle Miocene of Virginia. - Virginia Museum of Natural History Memoir 8:1-43. - A. C. Dooley - 2005.



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