Who said the snake has no foot? And who said she has no hand? Well, it may be that the species of snakes known today, even the most bizarre, actually have no limbs. However, according to research published in the journal Science, a finding is showing that in the past (as well as dinosaurs in the past) snakes seemed to have an easier way to "climb on the lemonade."

A fossil found in the Crato Formation, Ceará's limestone region, shows a snake shape with front and rear legs, which may help reveal more details about the history of snakes. The Four Feet Tetrapodophis aka species is being known as the first four-legged snake. She was a carnivorous predator and is estimated to have lived between 146 and 100 million years ago in the first half of the Cretaceous period. Its possible origin was in Gondwana, the ancient continent formed by South America and Africa.

Four-legged snake fossil found in Ceará - Image: Dave Martill, University of Portsmouth

The study of the fossil found was conducted by three researchers, the English Nicholas Longrich and David Martill, as well as the German co-author Helmut Tischlinger. They believe that the limbs presented by the reptile have gradually evolved over the generations, always shrinking in size. Thus, the specimen found in limestone is from a phase in which the predecessors became underground.

Martill of the University of Portsmouth explained in an interview with Discovery News that the taller paws were likely to hinder locomotion on the ground. “For gliding on burlap or sand (with small limbs), it's much better. As the paws are smaller, walking is more efficient, ”he added.

"Four Paws" Snake Hind Paws - Image: Dave Martill, University of Portsmouth

Martill and the other two scientists also believe that the undulating movements that aquatic species currently make to move around were pre-adapted at the time of the fossilized specimen. This strengthens the widespread thesis that snakes do not originate from aquatic species but rather from terrestrial lizards. For some time it was believed in aquatic origin, but now it is totally discarded, as the senior author of the research, Nicholas Longrich explained.

“The aquatic hypothesis is dead. In fact, it has been dead for some time, but with this discovery, the nails are being placed in the coffin. Aquatic snakes evolved from terrestrial snakes, ”added the researcher.

There is a noticeable difference between the front and rear limbs of the species found. The front legs are very small, which suggests better performance in other important functions such as mating and prey capture. Unlike lizards, four-legged snakes probably used their front limbs during breeding rituals and also to grasp prey.

Front legs appear to be smaller than rear legs, indicating expertise in other functions such as hunting and mating - Image: Dave Martill, University of Portsmouth

Scientists drew attention to the good preservation of the fossil in limestone. In the study, they claim that even some delicate fabrics remained well preserved. The good conditions allowed the researchers to come to other conclusions about the animal.

The head and the body

As the fossil appears, the "four-legged snake" skull was thin and slightly pointed, and the overall appearance is like that of some snake species. “This specimen had a long, thin snake body, probably with a forked tongue. The large belly scales are unique to snakes, and incredibly they remain preserved in the fossil, ”explained Nicholas Longrich.

Fossilized Four-legged Snake Head - Image: Helmut Tischlinger

It is not possible to say how big the adult specimens of this species were - the fossil found is from an animal just over 20 centimeters. However, scientists believe that the fossilized specimen died at a young age and could reach almost 1 meter in adulthood.

food

It is not just the unusually shaped skeleton that has been preserved in this dinosaur snake fossil. Throughout the body, a strange shape caught the attention of scientists, who, by the structure of the animal, found it to be part of its intestine preserved with remains of a creature from which it fed.

It is not possible to identify which animal was prey, but, according to scientists, it is probably a small gecko or lizard that has been bitten and squeezed before being swallowed. The initial assault resulted in the victim's circulation being cut off, causing death by organ failure. The content present in the fossilized skeleton also demonstrates a feeding format similar to that of the present-day boa constrictor, which swallows large whole prey.

Good conservation has preserved soft tissues and even an animal that served as food for the four-legged snake - Image: Helmut Tischlinger

Scientists also estimate that this young snake found was fed on dinosaur eggs as they lived in the same ecosystem as the planet's ancient inhabitants. Thus, researchers also believe that, in adulthood, these snakes could feed on dinosaur chicks, among other small animals.

Survival

The excavation and underground locomotion of the first snakes may be an explanation for the survival of the species during the most extinct period of dinosaurs 65 million years ago. However, not all snakes we know today can originate from the ancestors of this era.

Poisonous snakes, for example, were not present in the same environment as large reptiles. Studies have shown that these species only began to spread long after the dinosaurs went extinct approximately 34 million years ago.

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