Tetraceratops

Taxobox
name = "Tetraceratops"

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fossil_range = Early Permian
regnum = Animalia
phylum = Chordata
classis = Synapsida
ordo = Therapsida?
familia = Tetraceratopsidae
genus = "Tetraceratops"
binomial = "Tetraceratops insignis"
binomial_authority = Matthew 1908

"Tetraceratops insignis" ("Four-horned face emblem") was a lizard-like synapsid. It lived during the Early Permian period. According to a recent, controversial report, "T. insignis" is the first known therapsid. Other scientists, on the other hand, say that it is a more primitive species of synapsid, possibly an unusual, lizard-like pelycosaur, as originally thought. Evidence in favor of the pro-therapsid camp shows that "Tetraceratops"' temporal fenestra resembles that of biarmosuchians and other Permo-Triassic therapsids.

It is known from a single 90 millimeter long skull, discovered in Texas, during 1908.

Appearance

Contrary to its genus name, "Tetraceratops" actually has six horns, one pair being on the premaxilla bones, one pair on the prefrontal bones, and one pair on the angular processes of the mandible. When it was discovered and described in 1908, the skull was still embedded in a matrix, and only the premaxilla and prefrontal pairs were visible. In life, thus, it would have resembled a lizard with four horns on its snout, and a pair of large spines emanating from the corners of its jaw.

ee also

* Evolution of mammals
* Biarmosuchia

External links

* [http://www.palaeos.com/Vertebrates/Units/400Therapsida/100.html Palaeos.com's article on therapsids]
* [http://www.kheper.net/evolution/therapsida/Tetraceratops.html kheper.net ]