Aysheaia was a genus of Cambrian-aged soft-bodied, caterpillar-shaped fossil organisms with average body lengths of 1–6 cm.
Anatomy[]
Aysheaia has ten body segments, each of which has a pair of spiked, annulated legs. The animal is segmented, and looks somewhat like a bloated caterpillar with a few spines added on — including six finger-like projections around the mouth and two grasping legs on the "head." Each leg boasts a subterminal row of about six curved claws.[1] No jaw apparatus is evident.[2] The pair of legs marks the posterior end of the body, unlike in onychophorans where the anus projects posteriad; but this may be an adaptation to the terrestrial habit.
Ecology[]
Based on its association with sponge remains, it is believed that Aysheaia was a sponge grazer and may have protected itself from predators by seeking refuge within sponge colonies. Aysheaia probably used its claws to cling to sponges.
A terminal mouth is also seen in tardigrades that are omnivores or predators (but not detritovores or algavores) — this may provide an ecological signal.
Affinity[]
Aysheaia is a lobopodian, an extinct phylum of marine animals that are similar to modern terrestrial Onychophora (velvet worms). Notable differences are the lack of jaws and antennae, possible lack of visual organs,and the terminal mouth.