fossils

Crocodile ancestor’s extinction led to marine turtle evolution

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Franz
Anthony

Editor and Artist
One study suggests that the uneventful decline of crocodyliforms coincided with the diversification of modern marine turtles.

To most people, the group Crocodilia refers to the 23 species of crocodiles, alligators, and the gharial that still exist today. Back in the Mesozoic, their ancestors collectively known as crocodyliforms were far more diverse.


Around 145 million years ago, however, their diversity took a dip as the Jurassic Period came to an end. This extinction event also wiped out about 80% of species at that time.


A group of researchers from Imperial College London and University College London led by Jon Tennant of the Department of Earth Science and Engineering at Imperial analyzed a collection of 200 crocodyliform specimens to learn more about them.


This study suggests that when the predators were removed from the ecosystem, various creatures like early sea turtles flourished. Such a drastic extinction event happened when the crocodyliforms’ preferred habitats disappeared. Due to the drop in sea level, shallow marine habitats like lagoons and coastal swamps dried out by the end of the Jurassic.


In addition to the marine turtles, multiple marine predators such as sharks and the group of long-necked marine reptile known as plesiosaurs also diversified following the decline of the crocodyliforms.


The team expects to extend this study to other group of organisms, to better understand how they died out and adapted around this extinction event that started the Cretaceous Period.


Original findings published in EurekAlert!

Image Credit: Andrey Atuchin

8e6ac47821297aeee8c843e680637dca

Franz
Anthony

Editor and Artist


http://sulc.us/0kgg3
http://www.eartharchives.org/articles/decline-of-crocodile-ancestors-was-good-news-for-early-marine-turtles/