What were the ancient crocodiles (crocodylomorphs)? Ancestors of modern crocodiles

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:53

Many of us are interested in the ancient history of the Earth, and not only related to human civilization, but also what happened before the appearance of the first people on the planet. For example, what were ancient crocodiles and their immediate ancestors like?

Classification

The group of reptiles, which included, in addition to ancient crocodiles, pterosaurs, dinosaurs and other animals, is called Archosaurs. One of the areas of modern taxonomy, cladistics, also refers to this group of birds as descended from reptiles in their time. In addition to them, of the currently existing animals, this group includes modern crocodiles in the amount of three families (clade Eusuchia), included along with extinct species in the superorder Crocodylomorpha (Crocodylomorpha). The latter, in turn, are part of a larger group of Archosaurs called Crurotarses, or Pseudosuchia.

Previously, all known crocodilomorphs - both now existing and fossils - were included in the order Crocodilia. A new classification was proposed in the late 80s. XX century.

Differences between the ancestors of modern crocodiles

According to one of the hypotheses, ancient crocodiles livedon our planet already 250 million years ago, that is, in the Triassic period of the era, later called the Mesozoic. Crocodylomorphs of that time were smaller and relatively small. In the Cretaceous period, at the end of which the immediate ancestors of crocodiles appeared, this group was very numerous and included a variety of water and land forms, up to giant ones.

Modern crocodiles have many similar external features with their distant ancestors. Some of the reptile fossils will be briefly described below.

Protosuchia

Representatives of this suborder of the clade Crocodyliformes, also called procrocodylia by paleontologist Ferenc Nopcza, who singled them out into a separate taxon, lived on our planet 190-200 million years ago. They were relatively small (up to one and a half meters in length), which is why they themselves often became the prey of larger predators. Their limbs were longer than those of modern crocodiles, due to which these reptiles moved quickly enough on land. They also swam very well. Their body was covered with bony shields arranged in several rows, which provided relative protection from small predators. Protosuchians, like all, even the most ancient crocodiles, had sharp teeth.

Metriorhynchus

Representatives of this genus (family Metriorhynchids, clade Neosuchia), who lived on Earth 165-155 million years ago, had a rather long body - up to three meters. They had a well-defined tail fin, which made them look like fish and gave certain advantages when moving inwater. The body had a streamlined shape. On land, these ancient "crocodiles" could not move.

Notosuchii

This suborder, uniting crocodylomorphs of relatively small sizes, included terrestrial animals. They lived in Asia, Africa and South America during the Cretaceous period. The largest of these was the South American Baurusuchus pachecoi. It grew up to 4 meters long.

Dirosaurids

Representatives of the extinct family Dyrosauridae inhabited almost all areas of the Earth from the end of the Cretaceous to the Eocene periods. With their strongly elongated muzzles, they resembled modern gharials. These reptiles led an aquatic lifestyle. Representatives of Phosphatosaurus gavialoides belonging to this family had an impressive length - about 9 meters. They were common in the northwestern regions of Africa.

Sarcosuchus

Reptiles of the extinct genus Sarcosuchus (Sarcosuchus) in the modern classification belong to Crocodylomorphs, a family of Pholidosaurids, whose representatives had long snouts that widen at the end.

Representatives of the genus Sarcosuchus, who inhabited the territory of Africa at the beginning of the last period of the Mesozoic - Cretaceous, grew up to 10-12 meters in length and were thus 1.5-2 times larger than modern crocodiles!

The ancient crocodile Sarcosuchus imperial (imperator), first described by scientists in 1966, was no exception. The length of onethe skull of this reptile, found by researchers, is 160 cm. Most of the skeletons were found in 1997 - 2000. American paleontologist Paul Calistus Sereno. Prior to this, the size and appearance of these ancient animals (crocodiles) could only be judged by the remains of several teeth and scutes covering the body of reptiles discovered half a century earlier. They were found and described by the French scientist Albert-Felix de Lapparent. According to scientists, the mass of this giant monster exceeded 8 tons.

Giant ancient crocodile Sarcosuchus is gaining popularity with game developers. To date, it has been used in at least two of them - ARK: Survival Evolved and Jurassic world the game.

In closing

The article briefly describes only a small part of the representatives of crocodilomorphs. Their classification is quite complicated, and in the literature, especially popular, describing fossil animals, you can still find the term "crocodile" in relation to any representative of crocodilomorphs. Although it would be more correct to call only representatives of the clade Eusuchia crocodiles. It is to her that all modern and part of the extinct ancient crocodiles belong.