Onychophora

Abstract

Onychophorans, or “velvet worms” (Fig. 4.1), are multi-legged, terrestrial invertebrates that inhabit decaying logs, soil, and leaf litter of tropical and temperate forests on landmasses that have resulted from the breakup of Gondwana (Fig. 4.2A). The approximately 200 described species are classified into two major subgroups, the Peripatidae and Peripatopsidae, which might have diverged over 350 million years ago (Fig. 4.2A, B). The anatomy of onychophorans has changed little since the Early Cambrian, as they resemble fossil lobopodians – putative stem-group representatives of Panarthropoda (Onychophora + Tardigrada + Arthropoda).