Palaeos		Onychophora
Ecdysozoa		Overview

Ecdysozoa: Onychophora

PANARTHROPODA
|--Aysheaia
`--+--TARDIGRADA
   |
   `--+--ONYCHOPHORA
      |  |--Antennacanthopodia
      |  `--Euonychophora
      |     |--Helenodora
      |     `--+--Peripatopsidae
      |         `--Peripatidae
      `==DINOCARIDIDA
            `--ARTHROPODA

Velvet Worm (Euonychophora - Peripatidae) from the Amazon Rain Forest in Peru. Photograph taken by Thomas Stromberg, July 2002. Public domain, via Wikipedia

The Onychophora (literally "claw bearers", after the tiny claws at the tips of their stubby limbs) or velvet worms are what seem to be an ancient group, as apparently very similar forms were common and diverse during the Cambrian. This led to the idea that they are "living fossils" prehistoric relics from the time when animals were just evolving legs. But as with other such prehistoric survivors, appearances can be deceiving. Modern or crown group onychophora are highly specialised animals with unique slime glands for prey capture that are not found even in many Tertiary forms, while their stumpy-legged gait is quite different from that of the horizontal-legged crawlers that were their Cambrian forebears. While not very dicverse or abundant in relation to the more successful phyla such as the arthropods, molluscs, and vertebrates, they are clearly survivors, a unique evolutionary lineage successfully continuing alonmgside the big boys. MAK120426