Onychophora

Article By:

Ruhberg, Hilke Biozentrum Grindel und Zoologisches Museum, Universität Hamburg, Hamburg, Germany.

Peck, Stewart B. Department of Biology, Carleton University, Ottawa, Ontario, Canada.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.469300

A small phylum of soft-bodied terrestrial invertebrates, commonly known as velvet worms, living in tropical, subtropical, and temperate forests. The Onychophora is an archaic group of animals that has been described for some time as a missing or connecting link between annelids and arthropods, but recent research questions the validity of such statements. Onychophorans play a pivotal role in the discussion of arthropod phylogeny. At present, they are most commonly recognized as a sister group of the euarthropods, with a supposed close relationship to the Tardigrada (Panarthropoda concept). Onychophora comprises a single phylum of the same name. Currently, there are approximately 200 described species in two distinctive families—the Peripatopsidae and the Peripatidae. Recent application of molecular techniques has revealed many more as yet undescribed cryptic species. See also: Annelida; Arthropoda; Tardigrada

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