Scientists have refuted the theory of the origin of land animals from amphibians
The first animals to come out of the ocean onto land were creatures resembling modern crocodiles, not amphibians, as previously thought. This is stated in a study published on Thursday, February 12, in the scientific journal Popular Science.
The discovery is based on an analysis of fossils from the Mason Creek site, located southwest of Chicago. Scientists have studied the remains of baby embolomeres, ancient predators that dominated the planet's water bodies from 350 to 280 million years ago. Adults of these creatures reached 3 m in length, but the samples studied were only a few inches in size.
Jason Pardo, co-author of the study and researcher at the Field Museum of Natural History in the USA
In high school, many of us were taught a simplified version of evolution: that some fish evolved into amphibians, some of these amphibians into reptiles, and some of these reptiles into mammals. And our study shows that this basic premise, that the first four-legged vertebrates evolved like amphibians, is incorrect.
Using electron microscopy, experts from the Canadian Museum of Nature in Ottawa found that embolomers in the early stages of development lacked external gills and other features characteristic of tadpoles. This means that the ancient ancestors of land animals did not go through the classic metamorphosis of amphibians.
Experts have studied a number of different species representing the transition from fish to tetrapods, and found that none of them has anything like a tadpole. Pardo emphasized that in the absence of the tadpole stage, there is no metamorphosis. The life cycles of these early quadrupeds, he says, are more similar to those of humans or fish.
According to study co-author Aryan Mann, the location of Mason Creek is a unique "time capsule" that allows you to study even soft tissues and fragile remains of small individuals. The fossil of a baby embolomer, which became the key to the discovery, was found in the museum's collections 10 years ago, but it has only now been identified and studied in detail.
On June 10, Science Daily magazine revealed the reason for the slow development of the first animals on Earth. According to the publication, they could unintentionally slow down the growth of biodiversity due to breeding patterns that limit competition. The scientists cited the example of the Fractofusus creature, which reproduced asexually, producing genetically identical offspring connected by stolons — shoots similar to strawberry whiskers.
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