O ancestral mais antigo dos crocodilos foi desenterrado no Egito.

O fóssil estabelece firmemente o Norte da África como o "berço" da evolução dos crocodilos marinhos.

• 29 de outubro de 2025
• 18h10 (horário do leste dos EUA)
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Sobek era um antigo deus crocodilo egípcio e uma das principais inspirações para uma espécie recém-descoberta de crocodilo, o Wadisuchus kassabi, com 80 milhões de anos . 

A descoberta indica que a espécie — identificada a partir de um conjunto de fragmentos fossilizados de crânio e mandíbula recém-desenterrados no Oásis de Kharga, no sudoeste do Egito — tinha entre 3,5 e 4 metros de comprimento e capturava tartarugas ou peixes escorregadios com seu focinho alongado e dentes afiados como agulhas, segundo o The Jerusalem Post . Os restos mortais diferem marcadamente de espécies mais modernas, como o crocodilo-do-nilo (na foto). 

Tomografias computadorizadas e análises filogenéticas mostram que os novos espécimes representam a ocorrência mais antiga conhecida desses chamados crocodiliformes no registro fóssil , relatam pesquisadores esta semana no Zoological Journal of the Linnean Society . 

A descoberta estabelece definitivamente o Norte da África como o "berço" da evolução dos crocodilos marinhos e antecipa o surgimento desses animais em até 20 milhões de anos.

Prehistoric crocodiles' evolution mirrored in living species

Three species of Machimosaurus are shown with a human diver for scale.
Credit: Dmitry Bogdanov

Crocodiles which roamed the world's seas millions of years ago developed in similar ways to their modern-day relatives, a study has shown.

Fresh research into a group of prehistoric marine crocs known as Machimosaurus reveals key details of how and where they lived.

Each species adapted features that enabled them to live and hunt in a range of habitats, just like modern-day crocodiles. They varied in body length, body skeleton, skull and lower jaw shape, and in their teeth.

The ancient croc group included a nine-metre long saltwater species, which was adapted for living in open seas, and fed on marine turtles. Its closest relatives, by contrast, lived in coastal, choppy environments.

The prehistoric crocs' development mirrors those of today's crocodiles, whose saltwater varieties are far bigger and suited to larger territories compared with their smaller cousins that live closer to shore or in freshwater.

A team of researchers, led by the University of Edinburgh, examined fossil specimens from museums around Europe. From detailed analysis, they were able to determine key elements of the animals' anatomy and lifestyle, and concluded that not all were of the same species.

Until now, scientists were unsure whether more than one species of Machimosaurus existed. However, their findings show that there were at least three distinct species -- one of which has been fully identified for the first time. The study is published in the journal Royal Society Open Science.

Dr Mark Young, of the University of Edinburgh's School of GeoSciences, who led the study, said: "Interesting parallels can be seen between groups of ancient crocodiles and those living today, with some able to swim out in the open sea, with others restricted to the coast. With more fossils being discovered, we look forward to learning more about this giant group of Jurassic predators."

Note : The above story is based on materials provided by University of Edinburgh.

Read more : http://www.geologypage.com/2014/10/prehistoric-crocodiles-evolution.html#ixzz3g4HYFTYt
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Phylogenetics: True origin of true crocodiles

Nature 474, 545 (30 June 2011) doi:10.1038/474545a

Published online29 June 2011

Subject terms:

• Evolution
• Genetics and genomics

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The genus Crocodylus — that of the 'true' crocodiles (pictured) — seems to have originated in Australasia, rather than in Africa as is commonly thought.
Jamie Oaks at the University of Kansas in Lawrence analysed DNA-sequence data from 76 individuals across 23 crocodylian species. He compiled the data into a species tree and found that the animals originated from an ancestor living in the Indo-Pacific tropics some 11 million years ago, then quickly dispersed around the world. However, the analysis does not clarify whether the animals radiated westwards towards Africa or eastwards towards the Americas.
The work also revealed greater species diversity than previously established.

A. TOON & S. TOON/NATUREPL.COM

Evolution doi:10.1111/j.1558-5646.2011.01373.x (2011)