Peripatoides

Peripatoides novaezealandiae is a species complex of velvet worms in the genus Peripatoides, found throughout New Zealand. Like all velvet worms, these animals are nocturnal predators that spit a sticky slime to trap their prey. Individuals of Peripatoides novaezealandiae-complex usually have 15 pairs of legs.

Taxonomy
The Peripatoides novaezealandiae species complex consists of at least five reproductively isolated species described in 1998, each of which has 15 pairs of legs. These species (P. aurorbis, P. kawekaensis, P. novaezealandiae, P. morgani, and P. sympatrica) have no morphological characters that distinguish them although they are genetically differentiated. Peripatoides novaezealandiae and the cryptic species were considered nomina dubia by de Sena Oliveira et al. (2012) because type localities were identified in the species descriptions rather than holotype specimens. In 2014 the New Zealand Department of Conservation recognised these species. de Sena Oliveira (2023) later located the specimens used in the descriptions and as such no longer considered them nomina dubia. Three additional species were described in 2024.

Species
Peripatoides novaezealandiae-complex consists of the following species:


 * Peripatoides aurorbis Trewick, 1998
 * Peripatoides kawekaensis Trewick, 1998
 * Peripatoides morgani Trewick, 1998
 * Peripatoides novaezealandiae s. str. (Hutton, 1876)
 * Peripatoides otepoti Trewick et al., 2024
 * Peripatoides sympatrica Trewick, 1998
 * Peripatoides taitonga Trewick et al., 2024
 * Peripatoides waikaia Trewick et al., 2024

Natural global range
Peripatoides novaezealandiae-complex is endemic to New Zealand.

Habitat preferences
Peripatoides novaezealandiae-complex is usually found within or beneath rotting logs, though individuals have occasionally been discovered among leaf litter and beneath objects such as stones and rocks and in crevasses. Sufficient moisture is vital for all Onychophora as they cannot regulate water loss due to a lack of both a waxy cuticle and tracheal spiracles.

In 1989, several thousand of the P. novaezealandiae-complex were found on a property in Dunedin, living in an old kitchen dump among dry tins cans and sheets of roofing iron, and in a separate pile of bricks. The existence of the P. novaezealandiae-complex in a wide range of altitudes, forest, scrub and tussock, suggests that prey availability and moisture are more important than vegetation type when determining habitat suitability.

Reproduction
This genus exhibits lecithotrophic ovoviviparity; that is, mothers in this genus produce and retain yolky eggs in their uteri. The eggs are fertilized internally, and babies develop inside their mother until large enough to be born, in batches of 4–6, as colourless miniatures of the parents. These live-bearing Peripatoides have dermal-haemocoelic sperm transfer – which means sperm dissolve holes in the skin of the female to enter the body (haemolymph) anywhere on the body wall of the female.

Hutton originally claimed that individuals of Peripatoides novaezealandiae are hermaphroditic, possibly due to confusion regarding sperm storage sacs found within the female. This has since been contested, and more recent literature clearly designates individuals of P. novaezealandiae-complex as male or female. Sex can be identified in some morphs as young as two months after birth, but sexual differentiation is complete for all members of the P. novaezealandiae-complex by five months.

Juveniles go through three stages:


 * Stage A: wet and shiny integument (outer tissue). Needle-like spines of sensory papillae exposed.
 * Stage B: integument becomes more strongly pigmented and loses lustre. Sensory spines still exposed to some extent. This change is up to nine days after birth.
 * Stage C: integument fully pigmented and has no lustre. Sensory spines no longer exposed, and papillae resemble adult form. Time to reach this stage varies considerably with the location and morph, suggesting possible diagnostic differences between subspecies of the P. novaezealandiae-complex.

Peripatids grow by moulting the outer cuticle when it becomes too restrictive.

Diet and foraging
Like others in their family, Peripatoides novaezealandiae-complex is a nocturnal predator.

Captive individuals of P. novaezealandiae-complex have been sustained with flies. An abundance of centipedes have been found in logs that also contain P. novaezealandiae s. str., suggesting a possible predator-prey relationship.

Peripatids use their oral papillae to shoot out sticky slime which thickens upon contact with the air and covers prey in a strong, net-like structure. They approach and use their jaws to puncture the cuticle of the trapped animal, injecting digestive enzymes and sucking up the liquefied remains.

Conservation status
Peripatoides novaezealandiae-complex is classed as ‘not threatened’ according to the 2018 New Zealand Threat Classification System. In part, this is because the allozymatic species have not all been described and little is known about their distribution.

Scientific notes
Onychophora, including P. novaezealandiae-complex, are very difficult to rear in captivity. A German study of P. novaezealandiae-complex had some success keeping specimens alive long enough to birth young.

There is currently no known way to age individuals of P. novaezealandiae-complex, which makes it very difficult to compare individuals and fully understand their life history.

Cultural connections
The te reo Māori name for velvet worms is ngaokeoke which comes from the word ‘ngaoki’, to crawl.

When considering a new roading project, the presence of P. novaezealandiae-complex in Caversham Valley gave the location high conservation value. The New Zealand Transport Agency (NZTA) worked with the Department of Conservation, Dunedin City Council and Otago University to translocate any Peripatus impacted by the project, along with ongoing monitoring, management, and habitat enhancement. The discovery of ngaokeoke (P. novaezealandiae-complex) on their farm inspired Taranaki farming couple Damien and Jane Roper to form a partnership with the regional council to legally protect their 2.5 ha of native bush.