Thylacosmilus is a marsupial, and Smilodon is a mammal. Thylacosmilus and Smilodon both have saber teeth, but they do not share an ancestor that had saber teeth. What are saber teeth for these organisms?

A analogous structures

B homologous structures

C vestigial structures

D mutated structures

The right answer is analogous structures.

It is nevertheless interesting to note that several years before, a competition took place rather quickly between two types of mammals: the placentals and the marsupials, the Evolution having given in each of these two groups also armed individuals as we will see it next (We speak then of parallel evolution, that is the acquisition of similar characteristics in two species occupying the same space, not to be confused with a convergent evolution which gives identical attributes to two populations existing at times or in different ecosystems).

analogous structures