Petrolacosaurus

Taxobox
name = "Petrolacosaurus"
fossil_range = Late Carboniferous

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image_width = 250px
image_caption = "Petrolacosaurus kansensis"
regnum = Animalia
phylum = Chordata
classis = Sauropsida
subclassis = Diapsida
ordo = Araeoscelida
familia = Petrolacosauridae
genus = "Petrolacosaurus"
species = "P. kansensis"
binomial = "Petrolacosaurus kansensis"

"Petrolacosaurus" was a small, 40 centimeter long, diapsid reptile, one of the earliest known. It lived during the late Carboniferous period 300 million years ago. The prehistoric reptile's diet may have consisted mainly of small insects. "Petrolacosaurus" had distinctive canine-like secondary-sized teeth, a trait found primarily in therapsids and later mammals. Its fossils were found in Kansas.

In popular culture

"Petrolacosaurus" was featured in the BBC television show Walking with Monsters. As well as claiming that it was the ancestral synapsid, the program states that its heart was the template for our own, even though the anatomy of "Petrolacosaurus"'s organs and other soft tissue is completely unknown. It was portrayed as living alongside several species of giant arthropods, like giant Mesothelae spiders, and "Meganeura", a giant dragonfly, as well as anthracosaur amphibians like "Proterogyrinus".

However, because it was a primitive diapsid, it was not the common ancestor of either "Dimetrodon", or "Edaphosaurus". Both reptiles and Synapsids had a common ancestor. The ancestor of "Dimetrodon" was probably "Haptodus", a primitive synapsid from 300 million years ago to 280 million years ago. "Petrolacosaurus" was a typical, albeit primitive, diapsid, having two openings ("temporal fenestrae") on each side of its skull to add attachment points for jaw muscles. "Haptodus" had one hole behind each eye socket, called the temporal fenestra.

References

*cite book|first=Tim|last=Haines|coauthors=Paul Chambers|title=The Complete Guide to Prehistoric Life|page=p. 36|location=Canada|publisher= Firefly Books |year=2006