Kronosaurus is a genus within the pliosaurid family. It is a marine reptile that became extinct quite a few years ago. The specimens of this wonderful group of reptiles came to cohabit with the largest dinosaurs that inhabited our planet.

One of the main characteristics of this wonderful extinct aquatic reptile was its great size. The Kronosaurus looked really fierce, typical of the great predator it was. It is one of the most famous plesiosaurs, and above all it is considered one of the largest pliosaurs ever found.

Do you want to know more about it? At Dinosaurs we have the most complete information about the Kronosaurus you can imagine. Find out everything about this carnivorous dinosaur from the Cretaceous period!

Basic information about Kronosaurus

The Kronosaurus is certainly an interesting genus of aquatic predatory reptiles. Although we talk about dinosaurs in this page, this specimen should not be confused with one. Reptiles and dinosaurs have a close resemblance, but they are still different animals. Making this clear, let’s start by looking at the basic features about the Kronosaurus.

  • How long is it? – Approximately nine to ten and a half meters.
  • How tall is it? – Approximately 2 meters.
  • What’s its weight? – About 11 tons in weight.
  • When did he live? – About 125 million years ago until about 99 million years ago.
  • What’s your order? – It belongs to the order of the plesiosaurs.

The taxonomy of the Kronosaurus

Kingdom Animalia > Filo Chordata > Class Sauropsida > Superorder Sauropterygia > Order Plesiosauria > Family Pliosauridae > Clade Thalassophonea > Subfamily Brachaucheninae > Genus Kronosaurus

Within the genus Kronosaurus two species have been found, K.boyacensis and K.queenlandicus. Although currently there are only these two species of this genus, in the future it could increase or decrease according to future findings. We will take care to keep this information updated based on further changes.

The order: the plesiosaurs

Kronosaurus are classified as a genus of reptiles within the Order Plesiosauria. That is why before starting to talk more about them, it would be good to know a little more about their group because they adopt their morphology. Next we will talk above about the traits and characteristics of plesiosaurs.

The first plesiosaurs appeared during the Triassic period, in one of its last epochs. They were a fairly common family of reptiles at that time but when these specimens predominated it was undoubtedly during the Jurassic period.

From there they were inhabiting our planet until the great extinction that besides taking with it all the dinosaurs, it extinguished many other species, families and orders as it is the one of the reptiles plesiosaurids.

These spectacular reptiles had somewhat varied dimensions among the different species. We can find specimens that measure from 1.5 meters to the incredible length of 15 meters.

This size obviously varies based on the genus of the reptiles, although as we can see, there was a great diversity among the types of plesiosaurs in their time.

Plesiosaurs were mostly marine animals. This family of reptiles could be found more frequently in the oceans that came to dominate as large aquatic predators during the Cretaceous period. The origins of this extinct animal can be found in a family that resembles much more the current crocodile, the Nothosauridae.

If we go a little deeper into the physical features of plesiosaurs, the first thing that would stand out about them is their wide and flat body. The end of its body was endowed with a relatively short tail.

Plesiosaurs had four limbs that had evolved over time into four long fins. These fins would have been able to move thanks to the bony plates equipped with strong muscles that joined their extremities to their scapular waist and pelvis.

The position of their fins is quite strange and it is deduced from this that they probably used their four fins to move and propel themselves underwater. For the latter, it would have waved its limbs up and down, imitating the movement that modern birds would make to stay in the air, with the difference that plesiosaurs used all four fins and not two like birds and besides that, it does it in the water.

The characteristics of their fins are somewhat strange, since they were not flat like most aquatic species. The fins had a somewhat curved shape, with the point of maximum curvature at the top, i.e. they were convex in shape. This is quite curious and gives the impression that it would have “flown” into the water.

As mentioned above, the tails of the species in this family of reptiles were relatively short. Regarding function, the tail of plesiosaurs would have served to improve balance and control direction.

This deduction is made because their extremities would not have been sufficient to take manoeuvres that thanks to the tail they can perform. For example, in the ichthyosaurs or mosasaurs they would have been totally decisive to propel themselves in the water since their fins were not enough to do so.

It should be noted that they suffered from hyperphalangism. The plesiosaurs had up to eighteen phalanges in a row, something that we can also see in today’s whales.

The plesiosaurs evolved over time to take the final shape. Their limbs, for example, were not fins at first, but simply legs with which they moved along the shore. These extremities were very long and even as long as their trunk.

The pelvis and scapular girdle evolved greatly, developing a plate of wide bones over the lower part of her body. The latter grew due to the increase of muscles in that area in order to “shake up and down” the fins. However, this increase in the bone plate completely disables the knee and elbow joints, making the fins more robust and united.

The least changed of all the plesiosaurs is their trunk construction. Although there is a great difference in the shape of the neck and the skull in the different genera of plesiosaurs, the trunk maintains its structure in most of the specimens. With respect to the necks, these were quite rigid and would not have been able to bend it.

Within this order of reptiles we can notably differentiate two large types of specimens. This depends on the morphology of their neck, some specimens are classified as long-necked plesiosaurs and others as short-necked plesiosaurs. The first group, the long ones, are classified as Plesiosauromorphs while the short necked ones are called Pliosauromorphs.

Despite what one might think at first glance, long necks do not have longer vertebrae than short-necked ones. In the case of long necks, the plesiosaurromorphs owe the large size of their neck to the large number of cervical vertebrae and not to an increase in their size.

The one with the longest neck of all is the Elasmosaurus and has the spectacular figure of 76 cervical vertebrae no less.

This large number of vertebrae could be confused with the fact that these long-necked specimens have great flexibility, but this is not true. In spite of the large number of cervical vertebrae, their necks were really rigid and they were unable to bend them.

However, the pliosaurromorphs did have few cervical vertebrae, about 11, and here it is easier to deduce that their necks were rigid and robust.

Description of Kronosaurus

Well, we have already seen something else about the Plesiosaurian Order, the order to which the Kronosaurus belongs. Kronosaurus is a genus of reptiles belonging to the Plesiosaurian Order and as such it adopts its characteristics. Next we will talk about the general features of the Kronosaurus and the differences it has with the rest of the plesiosaurs.

Before going deeper into the physical features of Kronosaurus, let’s make clear the classification of the extinct reptile. As we said before, plesiosaurs are subdivided into two large groups depending on the size of the neck of the genera.

In the case of the Genus Kronosaurus, it is an extinct short-necked reptile. The latter classifies it directly within the family of pliosaurids, the short-necked plesiosaurs.

Talking more about its physical appearance, the Kronosaurus had a long head, its neck was relatively short and the body it had was quite rigid. To understand us, the head of the Kronosaurus was not very tall in terms of height thickness, but it was quite elongated, ending with a pointed snout.

It was propelled into the sea by the four fins it had. To help its fins, it also had the help of its tail, although because it was really short, it served little more than to control the direction.

The front fins were smaller than the rear fins. It is deduced that the Kronosaurus would have been a good swimmer, since it had very large and robust belly ribs between the two bands of its extremities. This would have given it a spectacular strength to swim in the seas without many problems.

The Kronosaurus differs from its cousins and brothers by the structure of its teeth. This particular genus has teeth over seven centimetres long. In addition, the longest tooth it has is thirty centimeters and these have crowns that are twelve centimeters long.

In spite of this, they are not sharp at all because they do not have cutting edges. The teeth of the Kronosaurus had a conical shape, without sharp parts, something quite peculiar and that allows them to be easily differentiated from other genera.

Discovery of the Kronosaurus

It has been two centuries since the first remains attributed to Kronosaurus were found. In 1899, Andrew Crombie de Hughenden discovered the remains of this specimen. Among these remains were six conical teeth that were taken to the Queensland Museum.

At that time it was not very well known which animal it belonged to. The ownership of those six conical teeth was an unknown for twenty-five years. The Director of the Queensland Museum, Heber Longman broke with the mystery and attributed these remains to a new species that he would describe and call Kronosaurus queenslandicus.

More remains of this extinct animal were later found. For example, in 1929, more remains of this extinct reptile, including a nearly complete skull, were found in the same place as the teeth.

This discovery revived the interest to continue investigating this specimen, and in 1932 a search expedition from the same Harvard University headed by Professor William E. Schevill left.

They found a pile of limestone rocks that contained the most complete Kronosaurus skeleton ever discovered. Thanks to this, a relatively complete skeleton could be assembled which was exhibited at Harvard in 1959.

The second most complete skeleton of Kronosaurus was found in Colombia. The curious thing about this discovery is that it was a simple farmer who wanted to work his land that discovered it.

When he was tilling, suddenly a huge stone appeared and when digging it was discovered that it was a relatively complete skeleton of a Kronosaurus. This second skeleton presents differences with the first one so Oliver Hampe decided in 1992 to classify it as a Kronosaurus boyacensis.

Why was it called Kronosaurus?

The reason for its designation is not entirely clear, although it is undoubtedly named after the Greek titan Cronos. The word saurus would come to refer to the fact that it is a reptile, since saurus means reptile. In contrast, the meaning of the species name Kronosaurus queenslandicus has its origin in the Queensland Museum. As we have mentioned, it was the director of the museum itself who gave the species this name.

When did Kronosaurus live?

Kronosaurus is a very ancient extinct reptile and to see it alive we would have to go back many millions of years. It came to share the habitat with a lot of species and genera of dinosaurs. Its existence dates back to about 125 million years ago and it disappeared completely about 99 million years ago.

This reptile was living on our planet from the Aptienian Age to the Albienian Age. These ages are the last of the Early Cretaceous, starting about 125 million years ago and ending about 100.5 million years ago. As you can see, the existence of these reptiles would have exceeded the end of the Early Cretaceous for some time to inhabit the early Late Cretaceous.

Where did the Kronosaurus live?

The areas where Kronosaurus lived are not known for sure. We must take into account that at any time new remains of Kronosaurus could be found in any area of our planet and that this would increase the area of its location.

Currently the remains of Kronosaurus were found in Australia and Colombia. That is why if we had to speculate on an area where this genus of extinct reptiles would have inhabited, it would probably be those countries.

Kronosaurus was a marine animal and as such would have inhabited the oceans and seas. That is why its habitat would have had to have some area of water. According to the data we have, this corresponds to the case of Colombia and Australia. In the Aptien and Albien ages, the areas of Colombia and Australia corresponded to areas covered by shallow inland seas.

What did Kronosaurus feed on?

Kronosaurus was a huge and spectacular reptile that lived in the seas. It was fearsome not only because of its appearance, but also because it was a hunter. In the fossil remains of Kronosaurus found in Queensland, remains of turtles and plesiosaurs were found. It could also have fed on more animals like giant squid, although there is no proof of that.