Mesosaurus tenuidens is the only species that has been found within the Genus Mesosaurus. It is a genus of reptiles that inhabited our planet millions of years ago, even before the dinosaurs.

The time scale in which it lived is known as the Paleozoic Era, prior to the Mesozoic Era which is the “Age of Dinosaurs”, and within this classification it specifically inhabited the subscale known as the Permian period.

Have you been left wanting more information about the Mesosaurus? Stay with us and discover everything about this incredible and peculiar carnivorous reptile of the Permian!


Basic information about Mesosaurus

The Mesosaurus was a large reptile that lived in areas of water. We are talking about a marine reptile that inhabited millions of years ago and although we talk about it in our dinosaur blog, it should not be confused with one.

We thought it was interesting to share some data about this ancient marine reptile that inhabited our planet even before the appearance of the first dinosaurs.

  • How long is it? – Approximately one meter long.
  • How tall is it? – It is not known.
  • What is its weight? – 34 kilograms.
  • When did he live? – He lived on our planet about 299 million years ago and it was not until about 272 million years ago that he finally disappeared completely.
  • What’s his family? – It belongs to the mesosaurid family.

The taxonomy of Mesosaurus

Kingdom Animalia > Filo Chordata > Class Reptilia > Clade Parareptilia > Order Mesosauria > Family Mesosauridae > Genus Mesosaurus

Within the genus mesosaurus we find only one species found, the tenuidens. In any case, we cannot rule out that in the future new species of this genus will be found. For our part, we will make sure that this section is kept up to date with new discoveries.

The family: mesosaurids

Before speaking more in depth about the genus Mesosaurus, it is convenient to know that these belonged to the Family Mesosauridae. That is why, in order to know more about them, it is inevitable not to talk about the family to which they belong.

When a genus is classified within a family is undoubtedly because it has the characteristics of that family. For this reason, we will now begin to investigate the main characteristics and features of mesosaurids.

Mesosaurids are a group of small aquatic reptiles and are the first known family of reptiles that are aquatic. It is estimated that they would have come from ancestors that were land reptiles. The fact that mesosaurids are aquatic animals cannot be fully guaranteed and some of them might have been amphibians.

Those belonging to this group were not noted for being fast swimmers, and their speed would have been between 0.15 and 0.85 m/s. However, little information is available about their sexual reproduction. It is suspected that they could have been viviparous, as embryos have been related within the uterus in adult specimens. However, isolated eggs from this family have also been found.

Description of Mesosaurus

There is not much information related to Mesosaurus. This is because not many remains of this genus have been found with which to work and draw more physical features from this extinct animal. Below we will tell you the characteristics of the Mesosaurus that have been able to be extracted in clear.

The genus Mesosaurus had a fairly elongated skull that exceeded in size of the Stereosternum. And not only the skull is larger than that of the Stereosternum, but it also had longer teeth. These teeth pointed outwards, and those at the tips of the jaws to a greater extent.

The elbows and ankles he possessed would have prevented him from walking on land. According to his anatomy, his movements were very restricted and if he had had the ability to walk on the ground, he would have been able to do so only for short periods of time.

The bones they had in their postcranial area are quite thick and they suffered from pachytostosis. Pakhiostosis is a process linked to vertebrate animals where the bones become thicker, usually due to additional layers of lamellar bone.

What differentiates Mesosaurus from other reptiles, however, is undoubtedly the possession of a kleithrum. The cleithrum is a species of dermal bone that overlaps the scapula and is mostly found in bony fishes and primitive tetrapods.

When did the Mesosaurus live?

Now that we have made it clearer about the characteristics of the genus, it remains to be seen when it was living on the planet. The fact is that these spectacular reptiles, incredible as it may seem, came to live on the planet before the dinosaurs existed.

Mesosaurus inhabited our world approximately 299 million years ago and was present until its extinction some 280 million years ago. This time period coincides with the Lower Permian. It was during the Lower Permian that the first carnivorous mammal-like reptiles appeared and dominated without a doubt.

Where did the Mesosaurus live?

We have already made it clear the time scale in which these specimens lived but we still don’t know where the Mesosaurus lived. This cannot be said for sure, since we do not know all the areas where the presence of this genus arrived, although we can confirm that it would have inhabited at least the areas of today’s South Africa and Eastern South America.

Although it was probably an aquatic animal, it would not have done so in deep waters. The natural habitat of this animal would have been the coastal areas due to their low depths. In addition, the remains of mesosaurus found in Urugay suggest that they were in a hypersaline environment rather than in a coastal area.

Did you know that? – The theory of continental drift is based in small part on Mesosaurus. Because South Africa and Eastern South America are two areas that are completely remote and separated by a large ocean. It is impossible that Mesosaurus would have crossed the Atlantic Ocean, so the only possibility is that both continents would have been joined in the past.

What do Mesosaurus feed on?

Mesosaurus was a carnivorous animal. It survived by feeding on small fish among other things. Although they were not very fast swimmers, they would have been able to swim faster than Pygocephalomorphic crustaceans. This is because these crustaceans would have been their favourite prey.

We hope that this entry with information about Mesosaurus has been useful for you. Any doubt, contribution or suggestion you may have related to this topic… Do not hesitate to use the comment box! We will be happy to read you!