Drepanosaurus fossil defies convention on how reptiles evolved and flourished

Drepanosaurus fossil defies convention on how reptiles evolved and flourished

Newly discovered fossils of a 200-million-year-old reptile are changing the common perceptions on how reptiles evolved and flourished. The Current Biology-published paper has unveiled that Drepanosaurus, which was found in a New Mexico quarry, was the size of a cat and lived in the trees.

It had a chameleon-like body but a bird-like head, but the most unusual feature in the species was its forearms, shared study’s lead researcher Dr. Adam Pritchard, of Yale University. Its index finger is significantly larger than its any of the other fingers. Also, the reptile has very-big sized claws.

Generally also, the forelimbs of tetrapods are known for being used for different purposes like for walking, digging, flying or swimming. In the study, the researchers have made 3D reconstructions of the reptile based on micro-CT scans of bones.

The researchers noticed that Drepanosaurus was not having parallel bones, the radius and the ulna that are found in other speices like elephant. It seems that the species has quite independently developed and have quite similarities that are being seen in groups like anteaters.

Drepanosaurus is said to have disappeared at the end of the Triassic. PalaeontologistDr Nicholas Fraser, of National Museums Scotland was of the view, “It was only useful in this one particular instance, where you have got a really specialisedfossorial animal - a digger”.

Fraser said that the Triassic period that spanned from around 252 million years ago to 201 million years ago saw the first dinosaurs. The period has witnessed a number of strange animals. It was a time of experimentation for the vertebrates, when it comes to body shapes and sizes.

A report published in BBC informed, "Newly discovered fossils suggest Drepanosaurus had huge hooked claws to dig insects from bark, much like today's anteaters in the forests of Central and South America. Scientists say the creature defies the convention on how reptiles evolved and flourished. Their research is published in the journal Current Biology."

"So all of these consistent patterns that we see across a huge range of tetrapods, regardless of their ecology, regardless of their ancestry, are violated by this animal," Dr Pritchard said.

"On the one hand, it extends the bounds of what we think the arm of tetrapod animals - those four-footed animals in the world - is capable of in terms of its development, in terms of evolution.

"And, it is also remarkable in what it evidences about the ecology, the lifestyle of the animal, in that it seems to have quite independently developed adaptations that we see today in modern groups like anteaters."

According to a report in CS Monitor by Eva Botkin-Kowacki, "The strange Drepanosaurus forelimbs might actually have been particularly well adapted for digging, according to new research published Thursday in the journal Current Biology. And this weird reptile could change scientists' ideas of what a forelimb can look like."

In almost every four-limbed animal from a dog to a wimpy-armed T. rex, the forearm has the same structure. Two long shaft-like bones, the radius and the ulna, are parallel and connect to a bunch of short, stocky wrist (carpal) bones. But the 212-million-year-old Drepanosaurus forearms look nothing like that.

"This is a huge departure from the conventional" structure, Nick Fraser, a vertebrate paleontologist at the National Museums Scotland who was not part of the research, tells the Monitor. "This tells us that it's probably not as much of a straightjacket as we thought. So then the question becomes, why hasn't this happened more often?"

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