Anthracotheriidae

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Anthracotheriidae
Fossil range: Middle Eocene to Late Pliocene

Arsinoitherium (top) and Bothriogenys fraasi (bottom)

Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Family:	†Anthracotheriidae

Subfamilies and Genera^[1]^[2]

†Anthracotheriinae

†Anthracotherium (type genus)
†Heptacodon
†Siamotherium

†Bothriodontinae

†Aepinacondon
†Afromeryx
†Arretotherium
†Brachyodus
†Bothriogenys
†Elomeryx
†Hemimeryx
†Kukusepasutanka
†Libycosaurus
†Merycopotamus
†Sivameryx

Anthracotheriidae is a family of extinct, hippopotamus-like artiodactyl ungulates related to both hippopotamuses and pigs. The oldest genus, Elomeryx, first appeared during the Middle Eocene in Asia. They thrived in Africa and Eurasia, with a few species ultimately entering North America during the Oligocene, and eventually died out in Europe and Africa during the Miocene, possibly due to a combination of climatic changes and competition with true hippopotami. The youngest genus, Merycopotamus, died out in Asia during the late Pliocene. The family is named after the first genus discovered, Anthracotherium, which means "coal beast," as the first fossils of it were found in Paleogene-aged coal beds in France.

In life, the average anthracothere would have resembled a skinny hippopotamus with a comparatively small, and narrow head. They had four or five toes on each foot, and broad feet suited to walking on soft mud. They had a full set of teeth, which, in some species, were adapted for digging up the roots of aquatic plants^[3].

Recent evidence gained from comparative gene sequencing further suggests that anthracotheres, as relatives of hippos,^[4] may be close to the ancestry of the whales.^[5]^[6] However, the earliest known anthracotheres appear in the fossil record in the Middle Eocene, well after the archaeocetes had taken up a totally aquatic lifestyle.

[edit] References

^ Kron, D.G., B.; Manning, E. (1998). "Anthracotheriidae", in Janis, C.M.; Scott, K.M.; and Jacobs, L.L. (eds.): Evolution of Tertiary mammals of North America. Cambridge: Cambridge University Press, 381–388. ISBN 0521355192.
^ Lihoreau, Fabrice and Jean-Renaud Boisserie, et alia.. "Anthracothere dental anatomy reveals a late Miocene Chado-Libyan bioprovince" (in PDF). Proceedings of the National Academy of Sciences (originally published online May 24, 2006).
^ (1999) in Palmer, D.: The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions, 268. ISBN 1-84028-152-9.
^ Boisserie, Jean-Renaud; Fabrice Lihoreau and Michel Brunet (February 2005). "The position of Hippopotamidae within Cetartiodactyla". Proceedings of the National Academy of Sciences 102 (5): 1537–1541. doi:10.1073/pnas.0409518102.
^ Gatesy, J.. "More DNA support for a Cetacea/Hippopotamidae clade: the blood-clotting protein gene gamma-fibrinogen". Molecular Biology and Evolution 14: 537–543. PMID 9159931.
^ Ursing,B.M. (1998). "Analyses of mitochondrial genomes strongly support a hippopotamus-whale clade". Proceedings of the Royal Society 265 (1412): 2251. doi:10.1098/rspb.1998.0567.