Onychophora, commonly known as velvet worms or more ambiguously as peripatus, is a phylum of elongate, soft-bodied, many-legged animals. In appearance they have variously been compared to worms with legs, caterpillars, and slugs. They prey upon other invertebrates, which they catch by ejecting an adhesive slime. Approximately 200 species of velvet worms have been described, although the true number of species is likely greater. The two extant families of velvet worms are Peripatidae and Peripatopsidae. They show a peculiar distribution, with the peripatids being predominantly equatorial and tropical, while the peripatopsids are all found south of the equator. It is the only phylum within Animalia that is wholly endemic to terrestrial environments, at least among extant members. Velvet worms are generally considered close relatives of the Arthropoda and Tardigrada, with which they form the proposed taxon Panarthropoda. This makes them of palaeontological interest, as they can help reconstruct the ancestral arthropod. Only two fossil species are confidently assigned to as onychophorans: Antennipatus from the Late Carboniferous, and Cretoperipatus from the Late Cretaceous, the latter belonging to Peripatidae. In modern zoology, they are particularly renowned for their curious mating behaviours and the bearing of live young in some species.
Macroperipatus is a genus of Neotropical velvet worms in the Peripatidae family. Velvet worms in this genus can have as few as 24 pairs of legs or as many as 42 leg pairs. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.
Mesoperipatus is a monospecific genus of velvet worm in the Peripatidae family, containing a single species Mesoperipatus tholloni. It is found in Gabon, making it the only known species of velvet worm in the tropics of Africa, and the only known species of peripatid velvet worm in Africa. Females of this species have 24 to 27 pairs of legs; males have 23 or 24. This species is viviparous, but too little is known of its embryology to describe its reproductive mode in any more detail; the presence of a placenta, for example, has not been confirmed.
Opisthopatus roseus is a species of velvet worm in the Peripatopsidae family. As traditionally defined, this species is rose pink with 18 pairs of legs. Known as the pink velvet worm, it is found only in the Weza Forest, a Mistbelt Forest in South Africa.
Speleoperipatus is a monospecific genus of velvet worm in the Peripatidae family, containing the single species Speleoperipatus spelaeus. This species is a pale greenish yellow, almost white, with 22 or 23 pairs of legs and no eyes. Specimens range from 27 mm to 34 mm in length. The minimum number of leg pairs found in this species (22) is also the minimum number found in the neotropical Peripatidae. This velvet worm is viviparous, with mothers supplying nourishment to their embryos through a placenta.
Leucopatus is a genus of velvet worm in the family Peripatopsidae, containing a single species, the blind velvet worm. It is found in northeast Tasmania, Australia, and is ovoviviparous.
Peripatidae is a family of velvet worms. The oldest putative representatives of the family herald from Burmese amber dated to the mid-Cretaceous, around 100 million years ago, with representatives from Dominican and Baltic amber attesting to a broader distribution in the Palaeogene / Neogene; molecular variability suggests that the family's crown group may have arisen in the early Mesozoic.
Peripatopsidae is one of the two living velvet worm families.
Eoperipatus is a Southeast Asian genus of velvet worm in the family Peripatidae. The number of legs in this genus varies within species as well as among species and ranges from 22 pairs to 25 pairs. This genus exhibits lecithotrophic ovoviviparity; that is, mothers in this genus retain yolky eggs in their uteri.
Heteroperipatus is a genus of Central American velvet worms in the Peripatidae family. The number of legs in this genus varies within species as well as among species and ranges from 26 pairs to 32 pairs. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.
Oroperipatus is a genus of Neotropical velvet worms in the family Peripatidae. Species in this genus are found in South America west of the Andes and in Mexico. Velvet worms in this genus can have as few as 22 pairs of legs or as many as 40 leg pairs. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.
Principapillatus is a monospecific genus of velvet worm containing the single species Principapillatus hitoyensis. Males of this species have 26 to 29 pairs of legs, usually 27 or 28; females have 30 to 32, usually 30 or 31. This velvet worm is viviparous, with mothers supplying nourishment to their embryos through a placenta. This species was discovered in Costa Rica.
Metaperipatus is a genus of velvet worms in the family Peripatopsidae that contains two species found in Chile, including Metaperipatus inae. This genus was created by the American zoologist Austin Hobart Clark in 1913 to contain the type species, M. blainvillei. Authorities believe M. blainvillei is a species complex, however, and some consider M. blainvillei a nomen dubium.
Paropisthopatus is a monospecific genus of velvet worm containing the single species Paropisthopatus umbrinus. Females of this species range from 20 mm to 70 mm in length. The type locality is in central Chile. Velvet worms in this genus have 16 pairs of legs. This genus exhibits matrotrophic viviparity, that is, mothers in this genus retain eggs in their uteri and supply nourishment to their embryos, but without any placenta.
Epiperipatus barbadensis is a species of velvet worm in the Peripatidae family, first described based on specimens from Barbados. It is one of the velvet worms that most often is kept in captivity, and was the first member of the Peripatidae family to be successfully maintained by hobbyist invertebrate keepers; it is easier to keep than the majority of other velvet worm species that have been tried, but still has specialized requirements that resemble those necessary for keeping poison dart frogs. E. barbadensis is social, nocturnal and viviparous, can live for several years, and feeds on small invertebrates that are caught by ejecting an adhesive slime from glands on their head.
Epiperipatus biolleyi is a species of velvet worm in the Peripatidae family. This species is red, without any pattern, on its dorsal surface. Females of this species have 28 to 32 pairs of legs; males have 25 to 30. Females range from 18 mm to 75 mm in length, with a mean length of 52 mm, whereas males range from 18 mm to 55 mm, with a mean length of 38 mm. The type locality is in Costa Rica.
Opisthopatus cinctipes is a species of velvet worm in the Peripatopsidae family. This species has 16 pairs of legs, all with claws and all used for walking. The color of the dorsal surface varies from blue to olive green. Females range from 7 mm to 50 mm in length, whereas males range from 6 mm to 36 mm. Like other velvet worms in this genus, this species exhibits matrotrophic viviparity, that is, mothers in this genus retain eggs in their uteri and supply nourishment to their embryos, but without any placenta. The type locality is in South Africa.
Peripatopsis moseleyi is a species of velvet worm in the Peripatopsidae family. Males of this species have 20 to 24 pairs of legs with claws ; females have 19 to 23 pairs of legs with claws. Females range from 11 mm to 75 mm in length, whereas males range from 9 mm to 50 mm. The type locality is in South Africa.
Peripatopsis sedgwicki is a species of velvet worm in the Peripatopsidae family. Also known as the Tsitsikamma velvet worm, this species has a narrow geographic distribution in South Africa but is especially abundant in the indigenous forest of the Tsitsikamma mountains. Recent phylogenetic analysis suggests that Peripatopsis sedgwicki is a species complex that contains three clades, each with a distinct geographic distribution, including at least one clade that may represent a novel species.
Peripatopsis leonina, the Lion's Hill velvet worm, is a species of velvet worm in the Peripatopsidae family. This species has 20 to 24 pairs of legs, usually 21 or 22 leg pairs, with the last pair of legs reduced. Females of this species range from 7 mm to 41 mm in length, whereas males range from 7 mm to 34 mm.
