Snakes have legs

Why did the snakes lose their legs?

Today they meander through many different habitats on earth - but why did the concept of leglessness in snakes originally develop? Stephan B. drew our attention to this topic - thank you very much!

Basically, two possible explanations are being considered for the origin of leglessness: The first snakes could have evolved from lizards living in water, which regressed their limbs as an adaptation to swimming. The other explanation is that the legless, slender and sleek body was initially an ideal adaptation to life underground.

To gain insights into the primal concept, the researchers led by Hongyu Yi from the University of Edinburgh examined the fossil of a snake that was still very close to the evolutionary origin of this group of animals: Dinilysia patagonica, up to two meters long, lived about 90 million times ago Years and thus represents one of the earliest known species of snake with completely receded limbs. The researchers focused on the extremely well-preserved skull of the snake fossil. They examined its features in detail using computed tomography.

The hearing system provides information on the way of life

The resulting recordings allow conclusions to be drawn about how the reptile's hearing system was once made, the researchers report. “The inner tubes of fossils can reveal important information,” emphasizes Yi. Comparisons with species of snakes and lizards living today showed that the archaic snake's hearing system had structures that are typical of reptiles that live and hunt in the ground. They enable them to detect the vibrations and sounds of their prey or enemies underground. However, these structures of the hearing system are not found in snake species that live in water or above the surface of the earth. In other words: D. patagonica was very likely to be a snake living in the ground.

According to the researchers, this finding in such an early snake species is a strong indication that the leglessness originally arose underground and only later proved to be beneficial for other habitats - such as the water. “How snakes lost their legs is an ancient mystery of science. It is becoming increasingly apparent, however, that this happened when their ancestors adapted to life in the ground, ”Yi sums up.

Source: University of Edinburgh, Science Advances, DOI: 10.1126 / sciadv.1500743

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October 7, 2018

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