How does turtle turtle evolve?

According to the July 10 issue of " Science ", in a new Japanese study, how turtle shells evolved: This turtle's ribs form a block, surrounding the shoulder bone.

In most other vertebrate animals, the position of the shoulder bone lies outside the rib, the process of this turtle is extremely special. Turtle body structure is different from other vertebrate animals at this point. So far, this is still a question that researchers have to think about, how has turtles evolved today, from their ancestors to molluscs?

Comparison of human bone systems and turtles
(Photo: Shigeru Kuratani and Hiroshi Nagashima)

Based on the embryo comparison of birds, rats and turtles, Hiroshi Nagashima and colleagues describe possible situations in each stage of the evolution of turtles. Research results show that, at the initial and embryonic stages of these three animals have the same development pattern, this may be because their ancestors have the same development .

However, in the process of embryo evolution in turtles, a shell section begins to fold inward, retaining a certain connection between bone and meat during development, but at the same time also creating a bond. New contacts are not available in other species such as reptiles, birds or mammals . With such folding results, the outer shell of the turtle's back begins to grow from the ribs, while the bones The shoulder reappears from another position.

In a related study, Olivier Rieppel explained, these findings are not the same as the previous view, because the evolution of the turtle shell was previously conceived to form from the small bone under the skin.

(Photo: Discovery)