Animal Diversity Web

Diversity

The genus Epiperipatus consists of 26 known neotropical velvet worm species under the phylum Onychophora and family Peripatidae. This genus has been relatively unstudied due to its rarity and cryptic nature. (Costa, et al., 2018)

Geographic Range

The velvet worms under the genus Epiperipatus are found in the Neotropical region that includes the Carribbean Islands and both Central and South America, and appear to be especially prevalent in Costa Rica and Brazil. (Costa and Giribet, 2021; Smith, 2016)

• Biogeographic Regions
• neotropical
  • native

Habitat

All velvet worms are exclusively terrestrial and can be found in humid tropical rainforests. They favor damp leaf litter, rotting wood, undersides of stones and other dark, moist environments. Some species even prefer to burrow underneath soil. These habitats are preferred as the velvet worm respirates through open holes on the sides of their bodies, leaving them susceptible to water loss. (Barquero-Gonzalez, et al., 2018; Costa and Giribet, 2021; Mayer, et al., 2015)

• Habitat Regions
• terrestrial

• Terrestrial Biomes
• rainforest

Systematic and Taxonomic History

Velvet worms are most closely related to arthropods and tardigrades, and are some of the oldest living taxa on Earth, with lineages remaining nearly unchanged for around 500 million years. Each of the two velvet worm families has a distinct lineage based off of where they were positioned when supercontinent Godwana fragmented and separated, Peripatidae being in the Neotropics and Peripatopsidae being in Australia and Southern Asia. Taxonomic analysis of this cryptic genus has been difficult due to similar morphological characteristics across the taxa and intraspecific variation, but molecular analysis is proving that Epiperipatus is a more genetically diverse group than we first thought. Analysis of RNA sequences is revealing the presence of rich cryptic variation amongst previously described species of Epiperipatus. (Oliviera, et al., 2011; Smith, 2016)

Physical Description

Members of Epiperipatus have hydrostatic skeletons covered with an external cuticle that is lined with numerous sensitive papillae to help them sense their environments and give them a 'velvety' appearance. They respirate through un-branched tracheal holes that line the sides of their bodies. They may have anywhere between 20 and 40 pairs of legs, which end in claws. On their heads, they have a pair of antennae and two oral papillae that help them capture their prey, along with a set of fangs. The perimeter of their mouths can be lined with chemoreceptors. The physical appearance of species found within Epiperipatus is consistent with most other Onychophorans, and there are many complicated gaps in the morphological study of this genus, such as an overall lack of defining characteristics. Epiperipatus species and all other velvet worms across the phylum Onychophora tend to look extremely similar and are nearly impossible to differentiate without DNA testing. (Bates, 2014; Costa, et al., 2018; Mayer, et al., 2015)

• Other Physical Features
• bilateral symmetry

Development

Epiperipatus development has not been described in literature.

Reproduction

Mating between velvet worms has rarely been seen, and has only been observed in a few species. All currently known species of velvet worm reproduce sexually, with the exception of Epiperipatus imthurni - no males have even been described in this species, and reproduction is done by parthogenesis. Within the family Peripatidae, all species are viviparous. The male usually deposits a spermatophore inside of the female, where the eggs will develop and hatch. The young emerge as fully formed, smaller versions of the adult worm. (Bates, 2014)

The reproductive cycle and breeding season of Epiperipatus have not been described in literature.

• Key Reproductive Features
• sexual
• viviparous

As soon as the worms are hatched and subsequently birthed, the fully formed young are able to exist on their own, and require no extra parental care. (Bates, 2014)

• Parental Investment
• precocial
• pre-hatching/birth
  • provisioning
    • female

Lifespan/Longevity

The lifespan of Epiperipatus has not been described in literature. In general, velvet worms can be expected to live up to 6 years in the wild, and their potential lifespan in captivity is unknown. (Mayer, et al., 2015)

Behavior

Velvet worms are nocturnal and leave their burrows at night to forage for small invertebrates. They are very cryptic and only leave their burrows to hunt. They are ambush predators and hunt by capturing prey in a sticky, protein-rich liquid that they expel from oral tubes near their mouths. Epiperipatus behavior has only been recorded in one undescribed species, Epiperipatus sp., in Costa Rica. The species was found to be most active during the dry season of December-April and were rarely seen on rainy nights. The species was also more active on dark nights absent of moonlight. (Barquero-Gonzalez, et al., 2018)

• Key Behaviors
• terricolous
• nocturnal
• motile

Communication and Perception

Communication and social hierarchy between velvet worms has been described in other families of velvet worms, but there is no published information on Epiperipatus specifically. Given the fact that their skin is lined with tiny, sensitive papillae, it is assumed that, like other velvet worms, Epiperipatus communicate with and collect information about other individuals by rubbing their papillae and/or antennae against each other. (Mayer, et al., 2015)

• Communication Channels
• tactile
• chemical

• Perception Channels
• tactile
• chemical

Food Habits

Epiperipatus species are insectivorous. Using specialized glands found deep within their oral tubes (papillae), these animals will trap small insects with a special glue-like substance expelled from the glands to entrap their prey. Then, the animal will consume the immobilized prey by injecting an enzyme that liquefies the insides of the insect, afterwards tearing it apart and consuming it with its pedipalps (fangs). (Mayer, et al., 2015; Mora, et al., 1996)

• Primary Diet
• carnivore
  • insectivore

Predation

Like all other velvet worms, Epiperipatus may be predated on by larger centipedes, spiders and birds. However, this is not very common as these animals spend almost all of their time hiding. Though mainly used for prey capture, the velvet worm may also use the secretions from its oral slime glands to ward off predators. (Mayer, et al., 2015)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • centipedes
  • spiders
  • birds

Ecosystem Roles

Epiperipatus are voracious predators of small insects, and may help keep insect populations from exploding in population and becoming problematic. Inversely, Epiperipatus serves as a food source for other animals, such as birds, helping those animal groups to thrive. Because so little is known about velvet worms and how they interact with their environments, there are no known specific ecosystem services that Epiperipatus provides as of yet. (Barquero-Gonzalez, et al., 2018)

Economic Importance for Humans: Positive

Velvet worms have recently begun to enter the exotic pet trade. Epiperipatus barbadensis is one of the most common velvet worm species kept in captivity. Velvet worm husbandry can be compared to poison dart frog husbandry, and while difficult for the average pet owner, can be an intriguing and unique addition to an experienced exotic pet owner's collection. (Barquero-Gonzalez, et al., 2016; Barquero-Gonzalez, et al., 2018)

• Positive Impacts
• pet trade

Economic Importance for Humans: Negative

There are no known adverse effects of Epiperipatus on humans.

Conservation Status

Evaluating the conservation status of Epiperipatus is nearly impossible due to conflicting and often incomplete descriptions of whether newly described species are valid or not, but it is often assumed that many new species are threatened or endangered because of their small, fragmented populations. Epiperipatus isthmicola is one example, as all of its known habitat is covered by urban development. Despite this, no described action is being taken to protect velvet worms at this time. (Barquero-Gonzalez, et al., 2016; Costa, et al., 2018; Oliviera, et al., 2012)

• IUCN Red List [Link]

  Not Evaluated

Other Comments

Thanks to molecular analysis, more species of Epiperipatus have been discovered in the past decade than any of the other families in Onychophora, and the number of species in the genus is continuing to grow.

Contributors

Emma Long (author), Colorado State University, Audrey Bowman (editor), Colorado State University.

References

Baker, C., R. Buckman-Young, C. Costa, G. Giribet. 2021. Phylogenomic Analysis of Velvet Worms (Onychophora) Uncovers an Evolutionary Radiation in the Neotropics. Molecular Biology and Evolution, Volume 28, Issue 12: 5391–5404.

Barquero-Gonzalez, J., A. Alvarado, S. Valle-Cubrero, J. Monge-Najera, B. Morera-Brenes. 2016. The geographic distribution of Costa Rican velvet worms (Onychophora: Peripatidae. Revista De Biologia Tropical, Volume 64, Issue 4: 1401-1414.

Barquero-Gonzalez, J., B. Morera-Brenes, J. Monge-Najera. 2018. The relationship between humidity, light and the activity pattern of a velvet worm, Epiperipatus sp (Onychophora: Peripatidae), from Bahia Drake, South Pacific of Costa Rica. Brazilian Journal of Biology, Volume 78, Issue 3: 408-413.

Bates, M. 2014. "The Creature Feature: 10 Fun Facts About Velvet Worms" (On-line). Accessed March 07, 2022 at https://www.wired.com/2014/03/the-creature-feature-10-fun-facts-about-velvet-worms/.

Costa, C., G. Fls, R. Pinto-Da-Rocha. 2021. Morphological and molecular phylogeny of Epiperipatus (Onychophora: Peripatidae): a combined approach. Zoological Journal of the Linnean Society, 192/3: 763-793.

Costa, C., A. Chagas Jr., R. Pinto-Da-Rocha. 2018. Redescription of Epiperipatus edwardsii, and descriptions of five new species of Epiperipatus from Brazil (Onychophora: Peripatidae). Zoologia, 35: 1-15.

Costa, C., G. Giribet. 2021. Panamanian velvet worms in the genus Epiperipatus, with notes on their taxonomy and distribution and the description of a new species (Onychophora, Peripatidae). Invertebrate Biology, Volume 140, Issue 3.

Lacorte, G., I. Oliviera, C. Da Fonseca. 2011. Phylogenetic relationships among the Epiperipatus lineages (Onychophora: Peripatidae) from the Minas Gerais State, Brazil. Zootaxa, Issue 2755: 57-65.

Mayer, G., F. Franziska, S. Treffkorn, V. Gross, I. Oliviera. 2015. Onychophora. Evolutionary Developmental Biology of Inverebrates, 3: 53-98.

Mongenajera, J. 1994. REPRODUCTIVE TRENDS, HABITAT TYPE AND BODY CHARACTERISTICS IN VELVET WORMS (ONYCHOPHORA. Revista De Biologia Tropical, Volume 42, Issue 3: 611-622.

Mora, M., A. Herrera, P. Leon. 1996. Electrophoretic analysis of adhesive secretions in onychophorans of the genus Epiperipatus (Onychophora: Peripatidae). Revista De Biologica Tropical, Volume 44, Issue 1: 147-152.

Oliviera, I., G. Lacorte, C. Fonseca, A. Wieloch, G. Mayer. 2011. Cryptic Speciation in Brazilian Epiperipatus (Onychophora: Peripatidae) Reveals an Underestimated Diversity among the Peripatid Velvet Worms. Plos One, Volume 3, Issue 3.

Oliviera, I., V. Read, G. Mayer. 2012. A world checklist of Onychophora (velvet worms), with notes on nomenclature and status of names. ZooKeys, 211: 1-70.

Smith, M. 2016. Evolution: Velvet Worm Biogeography. ScienceDirect, 26, 19: R882-R884.