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An Old & # 39; Legged Snake & # 39; The Fossil Discovery Tells An Amazing Story



In very rare cases, an extraordinary fossil is uncovered, providing an extraordinary insight into the evolution of a group of organisms.

This time, the beautifully preserved skull of an old snake with hind legs, Photos of rionegrina in Instagram Account Mrs. Najash rionegrina. Our work on this fossil was published in the journal. Scientific Developments.

These and other new fossils help answer long-standing questions about the origins of snakes, as well as how they lost their limbs and develop highly specialized skulls.

Fossil History

Photos of rionegrina in Instagram Account Mrs. Najash rionegrina it is named after Nahash (Hebrew for snakes), the snake in the biblical-legged Bible, and the province of Río Negro in Argentina, where fossils were discovered.

fossils Najash about 95 million years old and the first Nature a fragmentary skull and a partial body skeleton preserved in intact hind legs.

najash snake artist impressionNajash snake interpretation by an artist. (Raúl O. Gómez, University of Buenos Aires, Buenos Aires, Argentina)

The fossil snake that was cut in the back attracted media attention because it followed earlier reports of fossil sea snakes on the hind legs. What did he do Najash The uniqueness of this was that it was a terrestrial snake living in a desert, not a water snake living in the ocean.

In addition, the fossils were not flat compressed by the weight of the overlying sediments, and unlike fossil sea snakes, they were preserved in three dimensions.

Unfortunately, this is the first description Najash it was based on a multi-part skull. Snake evolution scientists were left to guess what the heads of these ancient animals looked like.

We know that common snakes are developed from lizards. We also know that snake skulls are the key to successful and highly specialized nutrition adaptations. New Najash Fossil skulls will be very informative about the evolution of the snake skull.

New discovery

It was a very hot day in February 2013 when Fernando Garberoglio, a undergraduate paleontology student from the Universidad de Buenos Aires, made his first field trip to the La Buitrera Paleontology Area in northern Patagonia in Argentina.

He had two paleontologists: Sebastián Apesteguía of the Universidad Maimónides and Guillermo Rougier of the University of Louisville.

Searching for fossil vertebrates is an elaborate discovery that requires patients. It requires you to be close to the soil, and scan sand, pebbles, rocks and sediments for a bone mark. You should take each piece, examine it closely, put it on the floor and repeat it an hour later.

In La Buitrera, you are caught by the hot sun, rained and frozen with cold Andean winds.

20191119 169374 1ujq53m(Fernando Garberoglio)

above: Student Fernando Garberoglio and paleontologist Sebastian Apesteguía conduct field work in the La Buitrera Paleontological Area in northern Patagonia, Argentina.

But it's all worth it. He finally took a pebble just a few inches long to find a small, old, bony face that looked at him, especially as with Garberoglio.

"I found a snake skull!"

Rougier asked the fossil to examine it and, in surprise, realized that Garberoglio was right – it was a 95-million-year-old 3D-preserved snake skull.

It's been 13 years. Najash and seven years have passed since Fernando's discovery. Today, the long hunt has awarded the treasure trove of new skulls and skeletons. Najash Fossil-rich places in La Buitrera.

Evolution of the skull

A long-standing hypothesis is that snakes evolved from blind, hollow lizard ancestors. A small worm-like nest snake, known as sklecophidians, has long been regarded as the most primitive living snake.

New Najash The fossil material shows that the skulls of the old serpent lineage were nothing like sklecophidian snakes. Instead, Najash species had large mouths with sharp teeth and some of the movable skull joints that were typical of most modern snakes.

However, they still retained the bony skull characteristics of the more typical lizards.

In evolutionary terms, Najash He says snakes are evolving into skull mobility, which is necessary to buy the very large hunting elements, a landmark feature of many modern snakes.

najash snake samples flindersNajash samples from LBPA. (University of Flinders)

Scientific prediction

Critical information is also preserved in the bone-bone details preserved in these new fossils. Najash. For example, for a very long time, the rod-like bone called the jugal, placed behind the eye of modern snakes, was thought to be equivalent to the postorbital bone of the lizard ancestors.

The idea followed that the jellie was not found in all snakes, fossils and moderns.

New skull Najash it certainly shows that this is not true. Bone under orbit Najash The more typical lizards have the same shape, position and connections as the L-shaped jugal.

This shows that the bottom stick of the jana was lost during the evolution of the snakes and left a stick-like jugal in modern snakes. Jugal is not lost postorbital bone.

These new examples Najash It is an excellent example of the predictive power of science. Hypotheses such as the presence of jugal in snakes can be supported by the discovery of new data that fulfill these predictions. As a result, it is seen that an old hypothesis is false and a new hypothesis is confirmed.

In short, the skull Najash He says that the ancestors' snakes were very similar to their close lizard relatives, such as big-bodied, big-headed lizards, such as Komodo dragons. This is in fact far from the idea that snakes may have evolved from tiny, blind, worm-like, small mouthed ancestors; No known ancient snake fossil resembles the so-called primitive, small-mouthed sklecophidian.Talk

Michael Caldwell, Professor of Vertebrate Paleontology, University of Alberta and Alessandro Palci, Research Fellow at Evolutionary Biology, University of Flinders.

This article is published from Speech under a Creative Commons license. Read the original article.


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