Evolution of the Crocodile

Evolution of the Crocodile

Timeline

Classification

Xilousuchus

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Unlike its modern-day descendants, the Xilousuchus had a sail on its back, which was popular in its time period. Also, its legs were not folded under it's body.

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Order: Crocodylia

Family:Crocodylidae

Genus: Crocodylus

Scientific Name: Crocodylus porosus.

Influences:

Phytosaur

Factors that influenced the evolution are environments, other organisms, and food resources.

The skeletal structure of an organism had to change to help them adapt to their environment. An example is having very moveable legs to navigate through water.

During the Mesozoic Era, there were many changes in development of organisms. The era started out with many small creatures, but over time, they became larger, leading to the need to develop protective features.

Even though they had the snouts of modern crocodiles, Phytosaurs were herbivores. Another difference is that their nostrils were not located at the end of their snouts. What sets these apart from Xilousuchus is that Phytosaurs had shorter legs and wider bodies.

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The separation of Pangaea drastically changed the size and features of the organisms. When it was just one large landmass, there was not a large need for water features. However, after separation, when water features began to cover parts of the world, the anatomy of these organisms had to change over generations to adapt.

Relatives

The closest modern relatives to crocodiles is birds because they both are the only living organisms from the Archosaur group.

Sacrosuchus

"SuperCroc"

"Flesh Crocodile"

Size: 40 feet long, up to 15 tons.

When: Mid Cretaceous

Location: Sub-Saharan Africa when it was covered with rivers

Food: Other creatures

SuperCroc had an unsually narrow snout; it took up about 3/4 of the entire jaw size (which was about 6 feet).

These ancestors have an usual bulbous depression at the end of their noses. It is unknown as to why they have these, so the trait may have become useless and died off.

This creature, like modern crocodiles, made its habitat swamps and fed off of other animals.

Modern day: Crocodylidae

Deinosuchus

Modern adaptations:

• Size depending on location and food resources.
• Very small pouches under the jaw the catch fish and other small organisms
• Sharp teeth to tear apart larger animals

This is probably the closest ancestor to modern-day crocodiles because they share similar snout and body structures and possible ways of attacking (lunging out of water).

Stomatosuchus

What makes this an interesting form is that it is believed to have smal, conical teeth on its upper jaw, little to no teeth on its lower, and a pelican-like pouch underneath. Because of it's structure and what it ate is still unknown, its believed to have eaten fish much like pelicans do.

Not much is known about this form, only theories remain. The only know fossil was destroyed in an allied bombing in WW2.