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 mammif�res constituant
deux genres, l'un le genre Rhizoprion de l'ordre des C�tec�s et du
groupe des Delphinoides; l'autre le genre Dynocyon de l'ordre des
Carnassiers et de la familie des Canid�s. - 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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