| Opisthopatus roseus | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Onychophora |
| Family: | Peripatopsidae |
| Genus: | Opisthopatus |
| Species: | O. roseus |
| Binomial name | |
| Opisthopatus roseus Lawrence, 1947 | |
Opisthopatus roseus is a species of velvet worm in the Peripatopsidae family. [2] [3] As traditionally defined, this species is rose pink with 18 pairs of legs. [4] [5] Known as the pink velvet worm, [1] it is found only in the Weza Forest, a Mistbelt Forest in South Africa.
Defining characteristics of O. roseus are its signature reddish pink colour and 18 pairs of clawed legs. [6] For pictures of the species, please visit research-grade observations on iNaturalist.
As a member of the Onychophora phylum, O. roseus has a chitin-covered body with numerous papillae that give it hydrophobic qualities and velvety appearance. [7]
Velvet worms have two antennae on the head, two simple-lensed eyes, and touch and smell sensitive hairs on their papillae. [7] Nephridia for excretion and osmoregulation are located at the base of the leg at every leg-bearing segment, except one where reproductive gonopores are located. [8] Gas exchange occurs through spiracles and tracheae, as well as diffusion through the body wall. [8] A pair of modified legs from which they squirt sticky protein-based slime to ensnare prey is called the oral tubes. [9] To handle prey after capture, they have sickle-shaped and toothed jaws on a fleshy pad on the underside of the head. [7]
In Opisthopatus genus, the last pair of legs is not reduced like in Peripatopsis genus, also found in South Africa. [6] The males and females are similar in morphology, although the shape of the genital opening is sexually dimorphic in Opisthopatus. [6]
The size of O. roseus is about 40 mm long and 3.5 mm wide. [6] They are uniform in colour, but legs and ventral side are lighter. [6] Their papillae are more numerous and closely set; they are smaller and arranged more regularly than in O. cinctipes. [6]
O. roseus is endemic to the Ngele mistbelt forest, near the town of Kokstad in the KwaZulu-Natal province of South Africa. [10]
R. F. Lawrence, who described the species in 1947, collected a specimen in this forest in 1945. [6] The only other specimen he collected there was from 1985 and is currently in the collection of the Hamburg University Museum. [6] The genetic voucher specimen was collected by Savel R. Daniels in 2012 and is housed in the Museum of Comparative Zoology at Harvard University. [11] The collection has both frozen DNA and a “very tiny piece” of the animal. [11]
As of March 2024, GBIF has 18 occurrences of O. roseus. [12] Of these, 77.8% are material samples, 16.7% are preserved specimens, and only 5.6% are human observations. [12] There is only one research-grade observation of the species in iNaturalist, detected in 1995. [13] Due to scarcity of records, O. roseus was considered to potentially have gone extinct in the late 20th century [14] and erroneously listed as extinct by the IUCN in 1996. [15]
Because of the threat of desiccation due to their spiracles being constantly open, [7] velvet worms live in saproxylic environments, like decaying wood logs and leaf litter. [10] They are photonegative (as they are largely nocturnal) and secretive, [7] making them hard to collect. [10]
Although all extant onychophorans are terrestrial, the fossil record shows that they were likely aquatic in the past, transitioning to land in the Ordovician period. [8] Notably, both marine Cambrian [16] and terrestrial Pennsylvanian [17] fossils are remarkably similar to extant velvet worms.
Like other velvet worms, O. roseus is a carnivore and feeds on small invertebrates, mainly soil-dwelling arthropods. [18] Once potential prey has been localized using the sensory antennae, the hunter secretes sticky slime, which is produced and stored in large glands, to entangle it. [18] The cuticle is punctured using a pair of jaws homologous to the chelicerae of chelicerates. [18] These are not mandibles, because they belong to the second body segment rather than the fourth. [18] The velvet worm then injects the prey with digestive saliva and sucks in the softened body parts using its pharynx. [18]
The slime is also used in self-defense, startling the potential predators, like birds, centipedes, and spiders [8] to give the worm time to escape. [7]
The Opisthopatus genus exhibits matrotrophic viviparity (also called ovoviviparity), in other words the eggs remain inside the uterus until hatching, so hatching and birth happen simultaneously. [19] Since the nutrients are provided by the mother, the eggs have little or no yolk. [19] They have no placental structures nor chorion, but the vitelline envelope persists until birth, [19] which happens after several months of development. [20] The adults mate throughout their lives and year-round, and with the insemination through the body wall, females keep sperm for a single season [21] . Notably, other Onychophora genera lay eggs which hatch after several months [19] , typically in the wetter and hotter season [21] . About 30 young are produced each year that are thought to reach maturity at nine to eleven months and live for six to seven years [20] .
Newborn velvet worms resemble the adults morphologically, but are smaller in size and have weaker integument pigmentation. [19] Although they have the full number of segments at birth, tracheae develop post-embryonically. [19]
After the development of O. cinctipes has been found to resemble the “long germ band” development of some insects, this unusual pattern was attributed to all of Opisthopatus. [22] Long germ insects specify all their segments as one step in the development process. [23] However, the development pattern of O. roseus follows an anterior-to-posterior gradient and is more similar to other velvet worms. [22]
Since pink velvet worms are ecdysozoans, they periodically molt their α-chitinous cuticle in order to grow; [24] the molting process is regulated by ecdysteroid hormones. [19] Unlike many arthropods, velvet worms do not metamorphose. [19]
There are 19 partial genomic nucleotide sequences and 13 partial protein sequences ascribed to O. roseus in GenBank. [25]
The Opisthopatus genus was described by William Frederick Purcell in 1899 and comprises 12 extant species, including O. roseus. [27] Opisthopatus and Peripatopsis are the two South African genera of the family Peripatopsidae. [10] This family belongs to Euonychophora order, Udeonychophora class, Onychophora phylum, and Panarthropda clade. [28]
Even though O. roseus is a sedentary organism, the population exhibits gene flow, as individuals living closely together exhibit different haplotypes. [10] There are two barcode index numbers (BINs), or barcode sequence clusters, suggesting two distinct genetic groups [29] .
Phylogenetic analysis, however, casts doubt on the traditional species delimitation based on morphology and militates in favor of a broader species definition based on a genetic clade instead. Phylogenetic results indicate that O. herbertorum , described as uniformly white with 17 leg pairs, [30] is a junior synonym of O. roseus. [31] This genetic clade also includes some velvet worms with 16 leg pairs that would traditionally be considered specimens of O. cinctipes . This broader understanding of O. roseus features intraspecific variation in leg number, ranging from 16 to 18 pairs, includes a range of colors from blood red or indigo to pearl white, and entails a broader geographic distribution in the southern part of the Drakensberg Mountains in Kwa-Zulu Natal province of South Africa. [4]
The pink velvet worm was previously considered extinct but is now listed as Critically Endangered by the IUCN Red List. Habitat loss and degradation are thought to be the cause of the species' decline. [1]
The pink velvet worm is endemic to the Ngele forest, which has been significantly disturbed by human activity. [10] In 1890, the construction of a sawmill and subsequent logging of indigenous trees fragmented the habitat. [10] More recently, the N2 national highway bisects the forest. [10] Additionally, commercial timber plantations and introduction of invasive species, as well as the practice of wood removal to minimize forest fires, can further limit the species’ range. [10] Overcollection is unlikely to be a significant threat to the population. [10]
Opisthopatus is a genus of South African velvet worms in the family Peripatopsidae. The number of legs in this genus range from 16 pairs to 18 pairs. The feet in this genus feature three distal leg papillae: one anterior, one posterior, and one median. Mothers in this genus give birth to live young. In particular, 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.
Peripatopsis is a genus of South African velvet worms in the Peripatopsidae family. The number of legs in this genus ranges from as few as 16 pairs to as many as 25 pairs and varies within species when the number is greater than 18 pairs. Velvet worms in this genus feature a last pair of legs that is rudimentary or reduced in size, mainly in males. The feet in this genus feature three distal leg papillae: two anterior and one posterior.
Peripatopsidae is one of the two living velvet worm families.
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.
Opisthopatus amaxhosa is a species of velvet worm in the family Peripatopsidae. This species is a clade in the O. cinctipes species complex. This species has 16 or 17 pairs of legs in both sexes and varies from light to dark pink on the dorsal surface and from dark to light brown on the ventral surface. Males of this species range from 12 mm to 14 mm in length. Also known as the Xhosa velvet worm, this species is found in the Eastern Cape province in South Africa.
Opisthopatus drakensbergi is a species of velvet worms in the family Peripatopsidae. This species is a clade in the O. cinctipes species complex. This species has 16 pairs of legs. Specimens are brown and slate black with a line down the middle of the back and a brown ventral surface. The original description of this species is based on a male holotype measuring 13 mm in length. This species is found at high altitude in the forests of the Drakensberg mountains in KwaZulu-Natal province in South Africa.
Opisthopatus highveldi is a species of velvet worm in the family Peripatopsidae. This species is a clade in the O. cinctipes species complex. This species has 16 pairs of legs and varies in color from brown to black to indigo. The original description of this species is based on two holotypes ranging from 16 mm to 17 mm in length. Also known as the Highveld velvet worm, this species is found in indigenous forest patches along the Highveld in Mpumalanga province in South Africa.
Opisthopatus kwazululandi is a species of velvet worm in the family Peripatopsidae. This species is part of the O. cinctipes species complex. This species has 16 pairs of legs. The color of its dorsal surface varies from brown to rose pink, and the ventral surface ranges from light brown to creamy white. The original description of this species is based on a male holotype measuring 16 mm in length and a female holotype measuring 22 mm in length. Also known as the coastal velvet worm, this species is found in Eastern Cape province and Kwazulu-Natal province in South Africa.
Opisthopatus laevis is a species of velvet worm in the Peripatopsidae family. This species has 16 pairs of legs. The type locality is in South Africa. The validity of this species is uncertain: Some authorities consider O. laevis invalid even as a subspecies of O. cinctipes, a similar species also found in South Africa, but other authorities recognize O. laevis as a separate species, citing the significant distance (570 km) between the type localities of these two species.
Opisthopatus natalensis is a species of velvet worm in the Peripatopsidae family. This species has 16 pairs of legs. The type locality is in South Africa. The validity of this species is uncertain: Although some authorities have deemed O. natalensis to be a subspecies of O. cinctipes, a similar species also found in South Africa, and others regard O. natalensis as invalid even as a subspecies, still other authorities recognize O. natalensis as a separate species, citing the significant distance between the type localities of these two species.
Opisthopatus swatii is a species of velvet worm in the family Peripatidae. This species is a clade in the O. cinctipes species complex. This species has 16 pairs of legs, and the color of the dorsal surface ranges from blue to slate black, while the ventral surface ranges from light brown to creamy white. The original description of this species is based on male holotypes ranging from 13 mm to 20 mm in length. Also known as the Swati velvet worm, this species is found in indigenous forest patches along the Highveld in Mpumalanga province in South Africa.
Peripatopsis capensis is a species of velvet worm in the Peripatopsidae family. This species has 18 pairs of legs: 17 pregenital leg pairs with claws plus one strongly reduced last pair without claws or spinous pads. Females of this species range from 9 mm to 70 mm in length, whereas males range from 6 mm to 54 mm. The native range of this species is limited to the Cape Peninsula of South Africa.
Peripatopsis hamerae is a species of velvet worm in the family Peripatopsidae. This species is a clade in the P. moseleyi species complex. The original description of this species is based on one specimen of each sex, each measuring 22 mm in length with a black dorsal surface and creamy white ventral surface. The male of this species has 22 pairs of pregenital legs and one pair of genital legs; the female has 23 pairs of pregenital legs and one pair of genital legs. Also known as the Kamala velvet worm, this species is known only from Groot Bruintjieshoogte in South Africa.
Peripatopsis janni is a species of velvet worm in the family Peripatopsidae. This species is a clade in the P. moseleyi species complex. The original description of this species is based on male specimens ranging from 15 mm to 30 mm in length. Live animals are dark green on the dorsal surface but greyish white on the ventral surface. The number of legs in males of this species varies from 21 pregenital pairs to 22 pregenital pairs. Also known as the Amathole velvet worm, this species is found in the Amathole mountains in South Africa.
Peripatopsis lawrencei is a species of velvet worm in the Peripatopsidae family. This species has 18 pairs of legs: 17 pregenital leg pairs plus one last pair that is strongly reduced and without claws or spinous pads. This species is restricted to the Theewaterskloof-Overstrand region of 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 alba, the white cave velvet worm, is a species of velvet worm in the family Peripatopsidae. This species is notable as one of only two species of velvet worm known to be troglobitic; the only other velvet worm known to be a troglobiont is Speleoperipatus spelaeus. The white cave velvet worm is rare and limited to one cave system on Table Mountain in South Africa.
Opisthopatus herbertorum is a species of velvet worm in the Peripatopsidae family. The type locality is in South Africa. As originally described, this species is uniformly white with 17 pairs of legs. Subsequent phylogenetic results, however, cast doubt on this species delimitation based on morphology, indicating instead that O. herbertorum is a junior synonym of O. roseus.
Opisthopatus baziya is a species of velvet worm in the family Peripatopsidae. This species has 16 or 17 pairs of legs in both sexes and ranges from rose pink to dark pink. Male specimens range from 17 mm to 31 mm in length; female specimens range from 13 mm to 26 mm in length. This species is endemic to the forests at Baziya in the Eastern Cape province of South Africa.
Opisthopatus camdebooi is a species of velvet worm in the family Peripatopsidae. This species is light pink and has 16 pairs of legs in both sexes. Males specimens range from 15 mm to 18 mm in length; female specimens range from 12 mm to 14 mm in length. Also known as the Camdeboo velvet worm, this species is endemic to the Camdeboo Nature Reserve in the Eastern Cape province of South Africa.
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