Typhloperipatus

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Typhloperipatus
Typhloperipatus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Onychophora
Family: Peripatidae
Genus: Typhloperipatus
Kemp, 1913
Species:
T. williamsoni
Binomial name
Typhloperipatus williamsoni
Kemp, 1913

Typhloperipatus is a genus of velvet worm in the family Peripatidae, containing the sole species Typhloperipatus williamsoni. [1] This genus contains the only species in the phylum Onychophora found in South Asia. [2] This species is also striking in that this velvet worm shows no external trace of eyes, [3] [4] although rudimentary optical vesicles are present internally. [5] This species is also notable for featuring males with the minimum number of legs (19 pairs) recorded in any velvet worm in the family Peripatidae. [6] [7]

Contents

Discovery

The species was discovered in the foothills of the Himalayas in northeastern India in 1911 and first described by Stanley Kemp in 1913. [3] [4] The species is named for Noel Williamson, a political officer at Sadiya who was murdered in 1911 along with his travelling companion Dr J.D. Gregorson, a physician working on a tea plantation. [3] These murders led to a punitive military expedition being organized by the British Indian government to the Abor region; Kemp, then an assistant superintendent at the Indian Museum at Calcutta was a zoologist assigned to this expedition. [3] [4] [8]

Kemp's assistant found the first three specimens in December 1911 near Rotung and the Dihang River gorge, where workers soon collected many more. Although the nearest known velvet worm species, from the Malay Peninsula, are typically found in dead wood, these were found mainly under large stones near the roots of trees. Subsequently some more specimens were found at the mouth of the Sireng stream and another specimen was found by the 32nd Sikh Pioneers while working between Upper Rotung and Rengin. [3] Kemp did not designate a holotype, but syntypes are deposited in the Natural History Museum of London. [1]

Morphology

This species is blind and has no eyes, an unusual trait for a velvet worm. [4] [3] The colour of the upperside is a deep umber brown with the tips of the antennae slightly paler brown. The papillae on the skin have pale tips and the underside is pale brown. Some individuals have a dark dorsal stripe. The outer blade of the jaw features two or sometimes three accessory teeth near the main tooth; the inner blade features three accessory teeth and eight to ten small denticles, with a short diastema between the accessory teeth and the denticles. [3]

Females have 20 pairs of legs; males usually have 19 leg pairs, but Kemp found one male with 20 pairs. Each leg features four complete spinous pads except for the last two leg pairs: The penultimate pair has only three pads on each leg, and the last pair has only two pads on each leg. Fine setae covers each pad. On the fourth and fifth leg pairs, the third most distal pad is divided into two parts, and near this division, the nephridial openings on each of those legs is located on the end of the longer anterior part of this pad. The feet have two distal papillae, one on each side of the claws (one anterior and one posterior). The genital opening is located between the penultimate pair of legs. The two pregenital leg pairs feature a crural gland at the base of each leg. [3]

Phylogeny

As Kemp noted, Typhloperipatus features a set of traits that are most similar to those found in the Eoperipatus species of Southeast Asia. For example, both genera feature feet with two distal papillae, one anterior and one posterior. [3] Furthermore, like Eoperipatus, Typhloperipatus exhibits lecithotrophic ovoviviparity; that is, mothers in both genera retain yolky eggs in their uteri. [9] Authors have since concluded that the genus Eoperipatus contains the closest extant relatives of Typhloperipatus. [10]

Several other traits, however, distinguish Typhloperipatus from Eoperipatus. For example, these genera are distinguished by not only the absence of eyes in Typhloperipatus but also the location of the nephridial openings on the fourth and fifth leg pairs. [3] These openings are located on the third pad on these legs in Typhloperipatus, but in Eoperipatus, these openings are located either on the fourth pad or between the third and fourth pad. [11] Furthermore, the anal glands in males of the genus Eoperipatus share a single opening between the last pair of legs, [11] [12] [13] whereas in Typhloperipatus, these male accessory glands instead have separate openings side by side close behind the last leg pair. [4]

A study of the fossil species Cretoperipatus burmiticus, embedded in Burmese amber from 100 million years ago, also finds two distal foot papillae, one anterior and one posterior, on this species. This distinctive feature places Cretoperipatus among the Asian Peripatidae (Typhloperipatus and Eoperipatus) and distinguishes this group from all other extant Peripatidae. [14] This study also identifies Typhloperipatus as the closest extant relative of Cretoperipatus. [14] [2]

Related Research Articles

<i>Peripatus</i> Genus of velvet worms

Peripatus is a genus of velvet worms in the Peripatidae family. The name "peripatus" is also used to refer to the Onychophora as a whole, although this group comprises many other genera besides Peripatus. The genus Peripatus is found in Central America, the Caribbean and northern South America. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.

<span class="mw-page-title-main">Peripatidae</span> Family of invertebrate animals

Peripatidae is a family of velvet worms. This family includes more than 90 described species distributed among 13 genera, but some authorities deem only 80 of these species to be valid. 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.

<i>Eoperipatus</i> Genus of velvet worms

Eoperipatus is a genus of velvet worms in the family Peripatidae. These velvet worms have been reported from locations throughout Southeast Asia, including Malaysia, Singapore, Thailand, and Vietnam. This genus exhibits lecithotrophic ovoviviparity; that is, mothers in this genus retain yolky eggs in their uteri.

<i>Epiperipatus</i> Genus of velvet worms

Epiperipatus is the most diverse genus of neotropical velvet worms in the family Peripatidae. Species in this genus are found in Central and South America. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.

<i>Oroperipatus</i> Genus of velvet worms

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. This genus is viviparous, with mothers supplying nourishment to their embryos through a placenta.

<i>Eoperipatus totoro</i> Species of velvet worm

Eoperipatus totoro is a species of velvet worm of the family Peripatidae. This species is notable as the first velvet worm from Vietnam to be formally described. As of 2024, E. totoro remains the only species of velvet worm from Vietnam to be described.

Cerradopatus is a monospecific genus of velvet worm containing the single species Cerradopatus sucuriuensis. Males of this species have 28 or 29 pairs of legs; females have 30 to 32. This species is native to the Brazilian savannah. This species 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.

Paraperipatus is a genus of velvet worms in the family Peripatopsidae. 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. Species in this genus are found in New Guinea and the surrounding islands, including the Maluku achipelago.

Eoperipatus horsti is a species of velvet worm in the Peripatidae family. Authorities have designated this velvet worm as the type species for the genus Eoperipatus, because among the species originally included in this genus, this species is the only one known from descriptions of both sexes. This species is found in Malaysia.

Epiperipatus cratensis is a species of velvet worm in the family Peripatidae. This species is found in northeastern Brazil. This velvet worm is notable as a small species of Epiperipatus with many legs.

Epiperipatus hilkae is a species of velvet worm in the Peripatidae family. This species is found in Costa Rica. This velvet worm is closely related to another species of Epiperipatus found in Costa Rica, E. isthmicola. The species E. hilkae is named in honor of the German zoologist Hilke Ruhberg for her extensive work on velvet worms.

Oroperipatus lankesteri is a species of velvet worm in the Peripatidae family. This velvet worm is notable for its large size, reaching 82 mm in length. This species is known only from its type locality in the northern Pacific lowlands of Ecuador.

Oroperipatus peruvianus is a species of velvet worm in the Peripatidae family. Males of this species have 34 pairs of legs; females have 36 or 37 pairs. This velvet worm is found in Peru.

Peripatus dominicae is a species of velvet worm in the Peripatidae family. The type locality for this species is on the Caribbean island of Dominica. Although the Canadian zoologist Stewart Peck introduced the name Peripatus dominicae dominicae in 1975 to distinguish the original species from other subspecies then assigned to P. dominicae, authorities now deem these subspecies to be separate species in light of the significant distances between their type localities.

Mongeperipatus solorzanoi, also known as Solórzano's velvet worm, is a species of velvet worm in the family Peripatidae. This species is the largest known velvet worm, reaching 22 cm in length. This velvet worm is found in the Caribbean coastal forest of Costa Rica.

Mongeperipatus is a genus of velvet worms in the family Peripatidae from Costa Rica. The biologists José Pablo Barquero-González, Steven Sánchez-Vargas, and Bernal Morera-Brenes introduced this genus in 2020 to contain the newly discovered type species, M. kekoldi, together with another species, M. solorzanoi. A phylogenetic analysis using DNA sequences placed these two species in their own monophyletic clade. Furthermore, these two species share morphological characters that indicate that these species do not belong in the other genera and instead belong together in a separate genus. The genus Mongeperipatus is named in honor of the Costa Rican biologist Julián Monge-Nájera.

Ooperipatellus nickmayeri is a species of oviparous velvet worm in the family Peripatopsidae. This species is larger than any other in the genus Ooperipatellus. With a body size exceeding 60 mm in females and 30 mm in males, these velvet worms can be more than twice as long as other species of this genus.

Epiperipatus titanicus is a species of velvet worm in the family Peripatidae. This velvet worm is known only from its type locality in the state of Alagoas in Brazil. The species name refers to the large size of its females and its numerous legs. This species features more legs than any other Brazilian species of velvet worm.

References

  1. 1 2 Oliveira, Ivo de Sena (2023-11-16). "An updated world checklist of velvet worms (Onychophora) with notes on nomenclature and status of names". ZooKeys (1184): 133–260. Bibcode:2023ZooK.1184..133O. doi: 10.3897/zookeys.1184.107286 . ISSN   1313-2970. PMC   10680090 . PMID   38023768.
  2. 1 2 Smith, Martin R. (2016). "Evolution: Velvet Worm Biogeography". Current Biology. 26 (19): R882–R884. Bibcode:2016CBio...26.R882S. doi:10.1016/j.cub.2016.07.067. ISSN   0960-9822. PMID   27728789.
  3. 1 2 3 4 5 6 7 8 9 10 Kemp, Stanley (1914). "Onychophora. Zoological results of the Abor expedition, 1911-1912". Records of the Indian Museum. 8: 471–492. doi: 10.5962/bhl.part.1194 . S2CID   88237018.
  4. 1 2 3 4 5 Kemp, Stanley (1913). "Preliminary note on a new genus of Onychophora from the N. E. Frontier of India". Records of the Indian Museum. 9: 241–242.
  5. ↑ Oliveira, Ivo de Sena; Franke, Franziska Anni; Hering, Lars; Schaffer, Stefan; Rowell, David M.; Weck-Heimann, Andreas; Monge-Nájera, Julián; Morera-Brenes, Bernal; Mayer, Georg (2012-12-17). "Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species". PLOS ONE. 7 (12): 1–20 [18]. Bibcode:2012PLoSO...751220O. doi: 10.1371/journal.pone.0051220 . ISSN   1932-6203. PMC   3524137 . PMID   23284667.
  6. ↑ Giribet, Gonzalo; Edgecombe, Gregory D. (2020-03-03). 30. Onychophora. Princeton University Press. doi:10.1515/9780691197067-032. ISBN   978-0-691-19706-7. S2CID   240645062.
  7. ↑ Mayer, Georg (2007-04-05). "Metaperipatus inae sp. nov. (Onychophora: Peripatopsidae) from Chile with a novel ovarian type and dermal insemination". Zootaxa. 1440 (1): 21–37. doi:10.11646/zootaxa.1440.1.2. ISSN   1175-5334 – via ResearchGate.
  8. ↑ Mackintosh, M.A. (1945). "Dr. Stanley W. Kemp, F.R.S." (PDF). Nature. 156 (3950): 41–42. Bibcode:1945Natur.156...41M. doi:10.1038/156041a0.
  9. ↑ Mayer, Georg; Franke, Franziska Anni; Treffkorn, Sandra; Gross, Vladimir; de Sena Oliveira, Ivo (2015), Wanninger, Andreas (ed.), "Onychophora", Evolutionary Developmental Biology of Invertebrates 3, Vienna: Springer Vienna, pp. 53–98, doi:10.1007/978-3-7091-1865-8_4, ISBN   978-3-7091-1864-1 , retrieved 2023-02-15
  10. ↑ Monge-Najera, Julian (1995). "Phylogeny, biogeography and reproductive trends in the Onychophora". Zoological Journal of the Linnean Society. 114: 21–60 [41-43]. doi:10.1111/j.1096-3642.1995.tb00111.x – via ResearchGate.
  11. 1 2 Oliveira, Ivo de Sena; Schaffer, Stefan; Kvartalnov, Pavel V.; Galoyan, Eduard A.; Palko, Igor V.; Weck-Heimann, Andreas; Geissler, Peter; Ruhberg, Hilke; Mayer, Georg (2013). "A new species of Eoperipatus (Onychophora) from Vietnam reveals novel morphological characters for the South-East Asian Peripatidae". Zoologischer Anzeiger. 252 (4): 495–510 [507]. Bibcode:2013ZooAn.252..495O. doi:10.1016/j.jcz.2013.01.001.
  12. ↑ Evans, Richard (1901). "On two new species of Onychophora from the Siamese Malay States". Quarterly Journal of Microscopical Science. 44: 473–538 [481–482].
  13. ↑ Oliveira, Ivo de Sena; Franke, Franziska Anni; Hering, Lars; Schaffer, Stefan; Rowell, David M.; Weck-Heimann, Andreas; Monge-Nájera, Julián; Morera-Brenes, Bernal; Mayer, Georg (2012-12-17). "Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species". PLOS ONE. 7 (12): e51220 [3, 18]. Bibcode:2012PLoSO...751220O. doi: 10.1371/journal.pone.0051220 . ISSN   1932-6203. PMC   3524137 . PMID   23284667.
  14. 1 2 Oliveira, Ivo de Sena; Bai, Ming; Jahn, Henry; Gross, Vladimir; Martin, Christine; Hammel, Jörg U.; Zhang, Weiwei; Mayer, Georg (2016). "Earliest Onychophoran in Amber Reveals Gondwanan Migration Patterns". Current Biology. 26 (19): 2594–2601. Bibcode:2016CBio...26.2594O. doi: 10.1016/j.cub.2016.07.023 . ISSN   0960-9822.
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