Suina
| Suina | |
|---|---|
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| Potamochoerus porcus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Suborder: | Suina Gray, 1868 |
| Families | |
The suborder Suina (also known as Suiformes) are lineage of mammals that today includes the families Suidae and Tayassuidae and their fossil kin.
Contents |
[edit] Classification
The suborder Suina includes Suidae (pig family) and Tayassuidae (peccary family). Some morphological studies also identified the hippopotamus family Hippopotamidae among the Suina.
The oreodonts, a branch of the tylopoda, were often considered suines due to the popular, though inaccurate, description of them as "ruminating hogs". Oreodonts are not suines, but are more closely related to camels. Similarly the precursors of the oreodonts, the entelodonts have long been classified as members of the Suina. Spaulding et al. have found them to be closer to whales, than to pigs in his Cetacodontamorpha.[1]
Hippopotamus were once thought to be part of the Suina, but a growing body of morphological and genetic evidence has suggested that they share a common ancestor not with Suina, but with Cetaceans—the Order which includes whales and dolphins. Whales and artiodactyls form a clade called Cetartiodactyla.[2]
| Cetartiodactyla |
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The most recent research into the origins of hippopotamidae suggests that hippos and whales shared a common semi-aquatic ancestor that branched off from other Artiodactyls around 60 million years ago.[3] Descendants of this hypothesized ancestor likely split into two branches around 54 million years ago.[4] One branch would evolve into cetaceans, possibly beginning with the proto-whale Pakicetus from 52 million years ago and other early whale ancestors, known as Archaeoceti, which eventually underwent aquatic adaptation into the almost completely aquatic cetaceans.[2]
[edit] Anatomy
The anatomy of the Suina is different compared to other even-toed ungulates. For example, they have maxillary (upper) teeth in front, which allow for proper chewing of food. In contrast, other even-toed ungulates, such as goats and deer, have front teeth only on the bottom. This doesn't let them chew very well, thus they swallow and regurgitate their food to allow rumination.
Most even-toed ungulates have a four-chambered stomach. In contrast, the Suina have a simple stomach that allows an omnivorous diet.
Most members of Suina have toes rather than hooves. While most artiodactyls have long slender legs, the Suina generally have short, stubby legs.
[edit] See also
[edit] References
- ^ Spaulding, M; O'Leary, MA; Gatesy, J (2009). Farke, Andrew Allen. ed. "Relationships of Cetacea (Artiodactyla) Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution". PloS one 4 (9): e7062. doi:10.1371/journal.pone.0007062. PMC 2740860. PMID 19774069. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2740860.
- ^ a b 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. PMC 547867. PMID 15677331. http://www.pnas.org/cgi/content/full/102/5/1537. Retrieved 2007-06-09.
- ^ Gatesy, J. (1 May 1997). "More DNA support for a Cetacea/Hippopotamidae clade: the blood-clotting protein gene gamma-fibrinogen". Molecular Biology and Evolution 14 (5): 537–543. PMID 9159931. http://mbe.oxfordjournals.org/cgi/content/abstract/14/5/537.
- ^ Ursing,B.M.; U. Arnason (1998). "Analyses of mitochondrial genomes strongly support a hippopotamus-whale clade". Proceedings of the Royal Society 265 (1412): 2251–5. doi:10.1098/rspb.1998.0567. PMC 1689531. PMID 9881471. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1689531.
[edit] External links
- http://www.paleocene-mammals.de/condylarths.htm
- http://www.ultimateungulate.com/Cetartiodactyla.html
