Vestigial structures take many forms: organs, behaviors, and even biochemical processes. Their defining characteristic is they are structures that a species has retained, but no longer serve their ...

Megachirella, the mother-of-all-lizards (and snakes). Davide Bonadonna/Nature . Around 252 ... as well as bones that survive today in modern lizards as reduced vestigial structures. ...

Like wisdom teeth or the appendix, a vestigial tail is believed to be a leftover of human evolution. While uncommon, it’s possible to be born with one. We’ll tell you what causes it, what it ...