What is the oldest living animal species?
Brachiopod Lingula. Having existed nearly unchanged for over 500 million years, and the horseshoe crab (limulus) has been on the planet for several hundred million years, too. Since the average “lifespan” of a species is only a few million years. Quote (answers.com): “The inarticulate brachiopod genus Lingula has the distinction of being the oldest, relatively evolutionarily unchanged animal known. The oldest Lingula occur in the very early Cambrian, roughly 550 million years ago. The origin of brachiopods is unknown. A possible ancestor is a sort of ancient “armored slug” known as Halkeria that was recently been found to have had small brachiopod-like shields on its head and tail.
