Crocodile fossils reveal parallel evolution in India and Amazon

During the middle of the Miocene, around 13 million years ago, this area was a huge lake-like wetland area with numerous species of animals, including a number of crocodiles. And Gryposuchus was the only long-snouted fish-eater among them.

It gets its species name from the South American storyteller deity Pachakumae. This new species, affectionately nicknamed “the storyteller” lacks “telescoped” orbits, unlike the other ancient gharials of the time.

This in itself is an odd feature, for all gharials have these telescoped eye openings. However, the skull is quite complete, so it is easier to ascertain the relationships of the animal and solve a great evolutionary puzzle that has boggled the minds of researchers for years. The lack of telescoped orbits may represent an ancestral condition of the South American gharials. This new species and other Gryposuchus possibly evolved in parallel with the Indian gharials. Their similar habits led to convergent evolution.

The exact evolutionary relationships of the modern gharial of the Indian Subcontinent, Gavialis gangeticus, have been tough to resolve and scientists are still trying to put these issues to rest. Researchers don’t know where the modern gharial and the slightly broader-snouted false gharial Tomistoma schlegelii diverged from one another. We do, however have a number of remains of these ancient creatures, with “the storyteller” adding to an ever-growing list of fossils.

The very oldest gharials date back to the Late Cretaceous of North America and many more appear all over the world in the fossil record. One of the best-known of all fossil gharials is of course, the South American Gryposuchus.

Original research published April 20, 2016, in PLOS ONE by Rodolfo Salas-Gismondi from the Université de Montpellier, France, and colleagues.

Vasika
Udurawane

Writer

All Posts