Different paths of evolution towards the same structure
2005/04/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
On the southern coast of Australia they have discovered the fossil of an ancient ancestor of the platypus, the monotremados. It is a new species for paleontologists who have baptized as Teinolophos trusle.
To that point it does not seem that this discovery is so important, but the surprise is in the middle ear of that monotremado, which has only one bone, three in modern monotremados, like the rest of mammals.
Logically, until now it was thought that the common ancestor of these groups of mammals had this complex structure of three ossicles. But T. trusleri lived 115 million years ago; by then the placental, marsupial and monotrembled mammals were already evolving.
Therefore, the monotremated mammals and the rest followed different evolutionary paths, but finally they reached the same structure, that of three ossicles.
