13-Million-Year-Old Crocodile Reveals Evolution Of Telescoping Eyes


Crocodiles’ eyes aren’t really appealing to humans or their prey. Those telescoped eyes allow them to be highly stealthy in their hunting and river dwelling, cruising along beneath the water surface with only the eyes and nostrils showing.

Thanks to a 13-million-year-old crocodile fossil, scientists found that South American and Indian species of the animal separately evolved to develop wide-spaced, excessively protruding eyes.

The fossil is of the Gryposuchus pachakamue, which belonged to the group of mostly extinct crocodiles called gavialoids. Researchers ventured to know the evolution behind the telescoped eyes shared by fossils of the extinct South American gavialoids and Indian gharial gavialoids on the other side of the world.

The study conducted by Rodolfo Salas-Gismondi and his team at the University of Montpellier in France analyzed the fossil found in Peru, where they probed 206 varying facial characteristics ranging from the head’s size to the snout’s length to the nostril’s width.

The unearthed fossil – dated to the Middle Miocene era and suggested to be a river dweller as it came from the swamp-ridden Pebas Formation – had only slightly telescoped eyes. Its Indian kin from the same period, however, had already developed that characteristic.

Based on the team’s analysis, it was practically parallel evolution at work: the crocodiles in the Western Hemisphere simply got started later than their Indian counterparts.

“Both South American and Indian species adopted a river-dwelling lifestyle, and it is likely that telescoped eyes were adaptive, helping them to catch fish in these habitats,” reported the authors.

These findings offer insights into whether a specific trait, such as telescoped eyes, could have evolved separately yet in parallel with similar animals from different habitats who found the same need for adaptation.

This seeming demosntration of parallel evolution sheds light on the process of evolution, which is deemed endless and simply continuously changing over the last 3.5 billion years. Could this mean that life on Earth will march on even if the human species ever becomes extinct?

The findings are published in the journal PLOS ONE.

Photo: Luke Price | Flickr

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