A world checklist of Onychophora (velvet worms), with notes on nomenclature and status of names.

Currently, the number of valid species of Onychophora is uncertain. To facilitate taxonomic work on this understudied animal group, we present an updated checklist for the two extant onychophoran subgroups, Peripatidae and Peripatopsidae, along with an assessment of the status of each species. According to our study, 82 species of Peripatidae and 115 species of Peripatopsidae have been described thus far. However, among these 197 species, 20 are nomina dubia due to major taxonomic inconsistencies. Apart from nomina dubia, many of the valid species also require revision, in particular representatives of Paraperipatus within the Peripatopsidae, and nearly all species of Peripatidae. In addition to extant representatives, the record of unambiguous fossils includes three species with uncertain relationship to the extant taxa. For all species, we provide a list of synonyms, information on types and type localities, as well as remarks on taxonomic and nomenclatural problems and misspellings. According to recent evidence of high endemism and cryptic speciation among the Peripatidae and Peripatopsidae, previous synonyms are revised. Putative mutations, subspecies and variations are either raised to the species status or synonymised with corresponding taxa. In our revised checklist, we follow the rules and recommendations of the International Code of Zoological Nomenclature to clarify previous inconsistencies.