Aysheaia

An Aysheaia is a small, 1-6cm, wormlike animal from the Middle Cambrian Burgess Shale of British Columbia. Similar forms are known from the Lower Cambrian Maotianshan shales of China. Aysheaia has 10 pairs of spiked. annulated legs attached to the ten body segments. The animal is segmented, and looks somewhat like a caterpillar constructed by the Michelin tire man with a few spines tacked on -- including six fingerlike projections around the mouth and two grasping legs on the "head". It apparently lived on or among sponges and is often found associated with sponges.

Unlike many early Cambrian forms whose relationships are puzzling or worse, Aysheaia is remarkably similar to an obscure modern phylum the Onychophora. The modern forms include about 60 genera somewhat resembling both the Annelids and the Arthropods. The principal differences are that the Onychophora are terrestrial and have jaws whereas Aysheaia was marine and jawless. The Onychophora are soft bodied and have no structures such as teeth that would be expected to fossilize well. They have no fossil record except possibly three very ancient forms Aysheaia. Xenusion, and just possibly Hallucigenia.

A illustration of Aysheaia is available at: http://www.hrw.com/science/si-science/biology/animals/burgess/payshia.html