Somewhere about 430 million years ago, a fish decided to try to go ashore, and the world has never been the same.
The question of how this happened fascinates biologists, so finding these fish species with a body suitable for locomotion on land could prove useful, even if most are apparently too lazy to use the “powers” of little Ariel. .
A skeleton study by an international team of researchers indicates that at least eleven species of fish could go ashore.
In this paper, published in the Journal of Morphology, scientists have successfully reconstructed the family tree of Balitoridae (Balitoridae), a family of small fish native to South, Southeast and East Asia. This family, also known as river or torrent loaches, currently consists of over 100 species.
These include cave fish (Cryptotora thamicola), the only living species of fish we know goes ashore, in a similar way to four-limbed vertebrates, such as reptiles or amphibians.
This ability was discovered in 2016, when scientists observed that the animal can walk sequentially sideways due to its robust pelvic girdle, in a manner similar to that of a salamander.
Through a comparative analysis of balitorid DNA, the team made an evolutionary map that allowed them to identify three dominant variants of the pelvic anatomy of this family. Specifically, they analyzed the bone structure of nearly 30 species of river lakes and established three categories of pelvic forms.
By analyzing the shape of the bone that connects the spine to the pelvic fins of some of the species tested, the scientists found that ten other species share the unusually robust pelvic girdle that cave fish have.
“Fish usually have nothing to do with the spine and the pelvic fin,” says Zachary Randall, a biologist at the Florida Museum. “We used to think that cave fish are totally unique. What is really interesting about this study is that it shows in detail that robust pelvic waists are more common than we thought in the river loach family.
Identification of these species it can be very helpful to find out how the first vertebrates got to land.
Lots of fish, like “hand” fish species from Tasmania, on the verge of extinction, moves by “walking” along the bottom of the ocean or lake. Due to the buoyancy of the water that supports most of their weight, their gait requires a much smaller adjustment of the conventional bone structure.
However, they still remain in their known environment and have no intention of evolving like their ancestor hundreds of millions of years ago.