Varanops

Varanops brevirostris

Varanops is one of those cool ancient reptiles that wasn't actually a Dinosaur. In fact, they lived before Dinosaurs even existed, and belonged to the same group that modern mammals eventually evolved out of millions of years later!

Varanops was not only a Synapsid-- it was also a Pelycosaur. In fact, its claim to fame is that it was one of the very last surviving Pelycosaurs. This group of Reptiles lived before the existence of Dinosaurs and included the more prominent Dimetrodon. (And for more information about Synapsids, check out that article!) Dimetrodon was gone around 280 million years ago, but Varanops made it at least another 20 million years.

They looked similar to today's large Monitor Lizards, and probably moved and behaved in a similar fashion (think Komodo Dragon). They consumed larger prey, as they had a very strong torso and legs, and were most likely terrestrial rather than arboreal.

Varanops went extinct around 260 million years ago, probably due to increased competition from all the new, Diapsid (Reptile), and Therapsid (Mammal-Like) predators. Therapsids actually evolved directly from other Pelycosaurs around 275 million years ago, making the Varanops that they deposed distant cousins!

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Status : Extinct for about 260 million years

Location : North America
Size : Length around 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Synapsida -- Family : †Varanopidae
Subfamily : †Varanodontinae -- Genus : †Varanops-- Species : † V. brevirostris

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Lystrosaurus

Lystrosaurus

Have you ever heard of Lystrosaurus? This amazing little creature was one of the very few lifeforms that actually survived the massive Permian/Triassic extinction event. Because they were able to make it through, they absolutely thrived during the Early Triassic, and were the most common land animals!

There are about half a dozen different species within the genus, and they have been found in what is now Southern Africa, Asia, and Antarctica. If that sounds like an odd distribution, remember that back 250 million years ago, those continents were actually joined together.

So what was Lytrosaurus? Well.. it was't a Dinosaur, despite the name. They actually weren't really reptiles either... Confusing, right? They were Therapsids, odd, mammal/reptile like creatures that would eventually evolve into the mammals we have today.

Lystrosaurus was about the size of a small pig and had short snouts, and only two, shovel-like teeth. They were herbivores that probably walked with a semi-spawling gate. There are many theories on why these animals survived when others did not. Some think that because they burrowed, they could cope with the low Oxygen air.  Others think that their small-ish size, semi-aquatic lifestyle, and varied diet helped to keep them going.

We know quite a bit about this extinct genus because their fossils are amazingly abundant. They were so common back in the Triassic that 95% of fossils in some sites belong to these animals!

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Status : Extinct for 250 million years

Location : South Africa, Asia, Antarctica
Size : Length up to 3ft (.9m)

Classification : Phylum : Chordata -- Class : Synapsida -- Order : Therapsida
Family : †Lystrosauridae -- Genus : †Lystrosaurus

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Dimetrodon

(Image Source)

Look at that picture to the right. What do you think that guy is? If you're thinking a Dinosaur, you'd actually be wrong. That guy over there is a Dimetrodon, an animal belonging to the genus of the same name that actually predated the Dinosaurs by 40 million years.

Want to know something else awesome?

Dimetrodons are actually more closely related to mammals than they are to reptiles. They are synapsids, tetrapods with one hole in the skull located closely behind each eye. Mammals are also synapsids, while animals like birds and reptiles are saurapsids. Synapsids were dominant creatures during the Permain period (299-251 million years ago), and the Dimetrodons in particular were apex predators. The name actually refers to the fact that they have two types of teeth, canines as well as sheering teeth.

(Image Source)

Dimetrodons are perhaps best known for the massive sails on their backs. This sail is actually made from spines that grow directly from the vertebrae. No one really knows for sure what the purpose of these sails was, but one theory is that they helped to regulate temperature. Dimetrodons were also pretty big for tetrapods of their day, with some species growing up to 13ft (4m).

Unfortunately, the Permian period met a disastrous end. Around 251 million years ago the largest mass extinction ever took place, wiping out 90% of all marine life and 70% of all land animals. Dimetrodons did not make it (in fact, they were already gone 30 million years before that-- around 280 million years ago), but some other synapsids did, including our very own distant relatives!

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