STL Science Center

STL Science Center

29 April 2011

Announcement for May and the first of the specials

May starts Sunday. This May, starting this week, will be a special departure from the Mesozoic. This month we're going to feature five special vertebrates from the Permian Era. Therefore, our first May Special Entry is:
This special month begins with the classic Permian animal: Dimetrodon. An early mammal-like reptile, Dimetrodon was a pelycosaur; a type of synapsid (a group that includes mammals and is named by a small opening in the skull behind the eyes which forms a small arch) that evolved before more advanced therapsid mammal-like reptiles and way before current sets of mammals we see before us today, such as ourselves. The most noticeable feature of Dimetrodon is that glorious sail coming out of its back. The purpose of the sail has many theories but one of the most popular has been its use in thermoregularity. Though it is a mammal-like reptile it is still believed to have been "cold-blooded" or ectothermic. There has been a slight shift from this theory of using the sail to warm or cool itself however, and the idea of sexual reproduction has become a new key idea as the sail could have been a billboard for attractiveness in Dimetrodon.

In part we owe our multi-use teeth to animals like Dimetrodon, or "two types of teeth" as its name means. Dimetrodon was one of the first animals on the block sporting specialized teeth for tearing meat and chewing. If you've ever watched a lizard, such as an iguana, eat then you've seen them step on food to tear it, or perhaps the infamous crocodilian death roll?, and then swallow it whole. The first synapsids, like Dimetrodon, sporting its new version of dental batteries, were among the first animals to chew their food with teeth designed to do so and to tear up food for easier digestion. Next time you say grace include Dimetrodon and other early synapsids in your thoughts!

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