Peripatopsidae is one of two extant families of velvet worm. This family includes more than 140 described species distributed among 41 genera, but some authorities deem only 131 of these species to be valid. The French zoologist Eugène Louis Bouvier proposed this family in 1905 with Peripatopsis as the type genus.
Description
The Peripatopsidae exhibit relatively many characteristics that are perceived as original or "primitive" with respect to the Peripatidae. The species in this family have relatively few legs, ranging from 13 pairs (in Ooperipatellus nanus) to a maximum of 29 pairs (in Paraperipatus papuensis). Behind or between the last leg pair is the genital opening (gonopore). This family includes both oviparous genera (e.g., Ooperipatellus and Ooperipatus) and viviparous genera, which adopt various modes of supplying nourishment to their embryos, ranging from lecithotrophic ovoviviparity (with yolky eggs retained in their uteri, e.g., Peripatoides) to matrotrophic viviparity (with little or no yolk in the eggs retained in their uteri and nourishment supplied by the mother instead, e.g., Metaperipatus, Opisthopatus, Paraperipatus, Paropisthopatus, and Peripatopsis). The Peripatopsidae lack a placenta, however, which has been found in velvet worms only in the neotropical Peripatidae.
Most genera in this family have only 15 pairs of legs; one genus has 15 or fewer (Regimitra, with 14 or 15 in the only species), and another genus includes only species with fewer than 15 (Ooperipatellus, with 13 or 14, depending on the species). Two genera are characterized by 16 pairs of legs (Occiperipatoides and Paropisthopatus), another genus has 15 or 16 (Peripatoides), and only four genera include velvet worms with more than 16: Opisthopatus (with 16 to 18), Peripatopsis (with 16 to 25), Metaperipatus (with 19 to 22), and Paraperipatus (with 21 to 29). Although leg number is fixed within most peripatopsid species, the four genera that feature more than 16 leg pairs exhibit some variation in leg number within species as well as among species. Peripatopsid species with more legs also feature greater intraspecific variation in leg number.
Distribution and habitat
The distribution of the Peripatopsidae (also known as southern velvet worms) is circumaustral; in particular, they inhabit Australasia, South Africa and Chile. Most genera in this family are found in Australia, one genus (Peripatoides) is found in New Zealand, and another (Ooperipatellus) is found in both; two genera (Opisthopatus and Peripatopsis) are found in South Africa, two others (Metaperipatus and Paropisthopatus) are found in Chile, and one other (Paraperipatus) is found in Indonesia and New Guinea.
Classification
Phylogeny
Peripatopsidae is divided into two main clades: one with members in South Africa and Chile, and another with members in Australasia. The majority of species belong to the Australasian clade, with most occurring in Australia. Below is a genus-level phylogeny of Peripatopsid velvet worms. This phylogenetic tree does not include all genera.
Genera The family contains the following genera:
Acanthokara Reid, 1996 Aethrikos Reid, 1996 Aktinothele Reid, 1996 Anoplokaros Reid, 1996 Austroperipatus Baehr, 1977 Baeothele Reid, 1996 Centrorumis Reid, 1996 Cephalofovea Ruhberg et al., 1988 Critolaus Reid, 1996 Dactylothele Reid, 1996 Diemenipatus Oliveira, Ruhberg, Rowell & Mayer, 2018 Dystactotylos Reid, 1996 Euperipatoides Ruhberg, 1985 Florelliceps Tait & Norman, 2001 Hylonomoipos Reid, 1996 Konothele Reid, 1996 Kumbadjena Reid, 2002 Lathropatus Reid, 2000 Leucopatus (Ruhberg, Mesibov, Briscoe & Tait, 1991) Leuropezos Reid, 1996 Mantonipatus Ruhberg, 1985 Metaperipatus Clark, 1913 Minyplanetes Reid, 1996 Nodocapitus Reid, 1996 Occiperipatoides Ruhberg, 1985 Ooperipatellus Ruhberg, 1985 Ooperipatus Dendy, 1900 Opisthopatus Purcell, 1899 Paraperipatus Ruhberg, 1985 Paropisthopatus Ruhberg, 1985 Peripatoides Pocock, 1894 Peripatopsis Pocock, 1894 Phallocephale Reid, 1996 Planipapillus Reid, 1996 Regimitra Reid, 1996 Ruhbergia Reid, 1996 Sphenoparme Reid, 1996 Tasmanipatus Ruhberg et al. 1991 Tetrameraden Reid, 1996 Vescerro Reid, 1996 Wambalana Reid, 1996
References