The new study points to a rare but first-occurring phenomenon that took place a million years ago: an Asian family of fish carrying the ability to walk on land on all fours. This is a discovery that can explain in detail how the first marine species were able to walk on the ground.
The South Asian River Ead is a family of small fish that often cling to rocks in fast water. Newly published in the Journal of Morphology, the new bone anatomy study of this species shows that at least 11 species of riverbass are capable of walking on the ground. Scientists have only witnessed one of them, a cave-dwelling blind fish known as Cryptotora thamicola, that can walk on land. And new research It turns out that Cryptotora thamicola is not the only species.
Reconstructed x-ray image of Cryptotora thamicola with higher resolution.
Brooke Flammang, a biologist at the New Jersey Institute of Technology and lead author of the study, analyzed 29 species of river gulls to write a new report. Using micro-CT scanning technology, Fammang et al. Analyzed and compared different specimens from different species of barramundi, dividing them into separate groups with different shapes, muscle groups and skeletal structures. together.
This international research group also conducted genetic analysis, took DNA samples of 72 barramundi to reproduce the evolutionary genealogy of the “legged” fish family.
The conclusions of body anatomy and genetic analysis showed that this family of fish is capable of walking on the ground.
“In the majority of families of fish houses, there is no bone relationship between the dorsal and the fin joint. These fish are different because they have hip bones”, Professor Flammang wrote in an email to the press. “In the body of the fish we studied, our analysis showed three distinct morphologies, from both thin and loosely connected to flexible joints and firm connections. We believe that the fish with the largest and most flexible ‘hip’ will have the best ability to walk“.
Cryptotora thamicola skeleton under many different angles.
Of the fishes analyzed, 11 species carried these flexible hips. More notably, the way they move in theory is similar to the limb movement of the newt when they walk on the ground. However, as mentioned above, science has only recorded one case of river gargoyle walking on the ground: Cryptotora thamicola species; In addition to traveling on land, they can also use all four limbs to climb up the waterfall.
According to Flammang, they stomped their fins to the ground, pushing their bodies forward in small steps. Most likely, this movement is an adaptive mechanism to the fast water often found in rivers and streams. For cave-dwelling fish, easy movement over many terrains allows them to access oxygen-rich water more easily.
As Zach Randall, a biologist working at the Florida Museum of Natural History and co-author of the study, points out, these properties “is most likely the key to keeping the fish from being washed away in the water they live in“. Researcher Randall also emphasized the detail of the report when the limb movement descriptions allow the fish to walk on the ground.
Cryptotora thamicola in natural environment.
Professor Flammang said that these fishes do not represent species, but rather a concept similar to the “lost link” between aquatic organisms and terrestrial limbs.
“But we also know that throughout evolution, living organisms have been continuously adapting to equivalent bodily changes, as a result of the pressure from natural selection. And by knowing that physics does not change over time, so we can learn from the movements produced by fish movements, use it to understand how extinct organisms travel. On the ground”Said Mrs. Flammang.
Species of the Homaloptera bilineata river climbing tree branches with limbs, it is unclear how capable of walking on the ground.
That is, the next goal of the research team: to clearly analyze the fish’s motor mechanism. They conduct initial research using high-speed cameras and muscle-tracking techniques.
“We may use live fish travel information to program the amphibian robot model the team is building.”Said Mrs. Flammang. “Then it is possible to apply this robotic fish to the fossil samples we have unearthed, in order to study the progression of morphology as well as the motor function of biomechanics.“.