ADW: Onychophora: INFORMATION

<!DOCTYPE html> <html xmlns:og="http://ogp.me/ns#" lang="en" xml:lang="en"> <head> <title>ADW: Onychophora: INFORMATION</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="canonical" href="https://animaldiversity.org/accounts/Onychophora/" /> <script type="text/javascript" src="//code.jquery.com/jquery-3.6.0.min.js"></script> <script type="text/javascript" src="//code.jquery.com/jquery-migrate-3.3.2.min.js"></script> <script type="text/javascript" src="/static/js/compat.js"></script> <link rel="shortcut icon" href="https://animaldiversity.org/favicon.ico" /> <link href="//fonts.googleapis.com/css?family=Gentium+Book+Basic:400,400italic,700,700italic" rel="stylesheet" type="text/css" /> <link href="//fonts.googleapis.com/css?family=PT+Sans:400,700,400italic,700italic" rel="stylesheet" type="text/css" /> <link rel="stylesheet" type="text/css" href="/static/bootstrap/css/bootstrap.css" /> <link rel="stylesheet" href="/static/css/pica.styles.css" /> <link rel="stylesheet" href="/static/css/pica.print.css" media="print" />  <link rel="stylesheet" type="text/css" href="/static/colorbox/colorbox.css" /> <meta property="og:url" content="https://animaldiversity.org/accounts/Onychophora/" /> <meta content="Onychophora (velvet worms)" property="og:title" /> <meta content="website" property="og:type" /> <meta content="Animal Diversity Web" property="og:site_name" /> <meta content="https://animaldiversity.org/collections/contributors/Grzimek_inverts/Onychophora/Cephalofovea_tomahmontis/medium.jpg" property="og:image" /> <meta name="twitter:card" content="summary" /> <meta name="twitter:site" content="@AnimalDiversity" /> <meta name="twitter:title" content="Onychophora (velvet worms)" /> <meta name="twitter:description" content="Read about Onychophora (velvet worms) on the Animal Diversity Web." /> <meta name="twitter:image:src" content="https://animaldiversity.org/collections/contributors/Grzimek_inverts/Onychophora/Cephalofovea_tomahmontis/medium.jpg" /> <meta name="twitter:image:height" content="480" /> <meta name="twitter:image:width" content="261" /> <meta name="twitter:url" content="https://animaldiversity.org/accounts/Onychophora/" /> <script type="text/javascript" src="/static/js/Hyphenator.js"></script> <link rel="stylesheet" href="/static/social-likes/social-likes_birman.css" /> <style> .social-likes { margin: 0; } .social-likes__widget { margin: 0; } </style>   </head> <body> <div id="outerwrap"> <div id="header" aria-role="header"> <h1> <a id="homelink" href="/">Animal Diversity Web</a> </h1> <div class="umlinks"> <div class="relative"> <a href="https://lsa.umich.edu/ummz/" id="ummzlink">University of Michigan Museum of Zoology</a> <a href="https://www.umich.edu/" id="umlink">University of Michigan</a> </div> </div> </div> <div id="wrap" class="gradient"> <div class="container-fluid"> <div class="row-fluid"> <div class="span2 sidebar left"> <ul class="nav nav-tabs nav-stacked" id="sitemap"> <li> <a href="/">Home</a> </li> <li> <a href="/about/">About Us</a> </li> <li> <a href="/animal_names/">About Animal Names</a> </li> <li> <a href="/teach/">Educational Resources</a> </li> <li> <a href="/collections/">Special Collections</a> </li> <li> <a href="/glossary/">Glossary</a> </li> <li> <a href="/accounts/Animalia/">Browse Animalia</a> </li> </ul> <h2 class="offscreen">More Information</h2> <div class="well"> <h3>Additional Information</h3> <ul class="unstyled"> <li> <a href="http://eol.org/search/?q=Onychophora&search=Go">Encyclopedia of Life</a> </li> </ul> </div> </div> <div class="span7_5 blahblahblah main" aria-role="main"> <h2 class="rank-unspecified">Onychophora<span class="vernacular-name">velvet worms</span></h2> <div class="social-likes" data-counters="no"> <div class="facebook" title="Share link on Facebook">Facebook</div> <div class="twitter" title="Share link on Twitter">Twitter</div> </div> <div class="snapshots" aria-hidden="true"> <ul> <li> <a href="/accounts/Onychophora/pictures/collections/contributors/Grzimek_inverts/Onychophora/Cephalofovea_tomahmontis/"> <img alt=" " src="/collections/contributors/Grzimek_inverts/Onychophora/Cephalofovea_tomahmontis/button.jpg" border="0" /> </a> </li> <li> <a href="/accounts/Onychophora/pictures/collections/contributors/Grzimek_inverts/Onychophora/Epiperipatus_biolleyi/"> <img alt=" " src="/collections/contributors/Grzimek_inverts/Onychophora/Epiperipatus_biolleyi/button.jpg" border="0" /> </a> </li> </ul> </div> <div class="byline">By Jeremy Wright</div> <nav class="contents"> <ul> <li> <a href="#diversity">Diversity</a> </li> <li> <a href="#geographic_range">Geographic Range</a> </li> <li> <a href="#habitat">Habitat</a> </li> <li> <a href="#taxonomic_history">Systematic and Taxonomic History</a> </li> <li> <a href="#physical_description">Physical Description</a> </li> <li> <a href="#development">Development</a> </li> <li> <a href="#reproduction">Reproduction</a> </li> </ul> <ul> <li> <a href="#lifespan_longevity">Lifespan/Longevity</a> </li> <li> <a href="#behavior">Behavior</a> </li> <li> <a href="#communication">Communication and Perception</a> </li> <li> <a href="#food_habits">Food Habits</a> </li> <li> <a href="#predation">Predation</a> </li> <li> <a href="#ecosystem_roles">Ecosystem Roles</a> </li> <li> <a href="#economic_importance_positive">Economic Importance for Humans: Positive</a> </li> </ul> <ul> <li> <a href="#economic_importance_negative">Economic Importance for Humans: Negative</a> </li> <li> <a href="#conservation_status">Conservation Status</a> </li> <li> <a href="#comments">Other Comments</a> </li> <li> <a href="#contributors">Contributors</a> </li> <li> <a href="#references">References</a> </li> </ul> </nav> <div class="inner-wrap"> <section class="hyphenate"> <h3 id="diversity">Diversity</h3> <p audience="advanced intermediate">Phylum <span class="taxon-link rank-unspecified">Onychophora</span>, or velvet worms, contains approximately 180 species of bilaterally symmetrical, coelomate organisms that somewhat resemble caterpillars. Onychophorans range from 5 mm to 15 cm in length, with homonomous bodies and small heads. The head carries a pair of annulated, fleshy antennae and a pair of small eyes at their bases, with large, chitinous lenses and a well-developed retinal layer, as well as a pair of jaws surrounded by circular lips, and a pair of fleshy oral papillae, also known as slime papillae. The sticky secretions produced by the latter structures are used to capture prey, which includes other small invertebrates. Living species are divided into two families, <a class="taxon-link rank-family" href="/accounts/Peripatidae/">Peripatidae</a> and <a class="taxon-link rank-family" href="/accounts/Peripatopsidae/">Peripatopsidae</a>, which live in mutually exclusive geographical regions; peripatids are circumtropical, while peripatopsids are circumaustral. Members of the two families differ in their number of legs (generally greater in peripatids), the position of their gonopore (on a more posterior body segment in peripatopsids), and their reproductive habits. All of the currently known living species are terrestrial, living mainly in dark, moist microhabitats. Research indicates that they are either modified <a class="taxon-link" href="/accounts/Arthropoda/">arthropods</a> or represent a link between <a class="taxon-link" href="/accounts/Annelida/">annelids</a> and arthropods, most recent molecular phylogenies favor the first hypothesis. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>; <a href="#228415AB-7E00-11E2-9D98-002500F14F28" class="citation">Zhang, 2011</a>)</span></p> </section> <section class="hyphenate"> <h3 id="geographic_range">Geographic Range</h3> <p audience="advanced intermediate">The two <span class="taxon-link">onychophoran</span> families live in mutually exclusive regions. <a class="taxon-link" href="/accounts/Peripatidae/">Peripatids</a> are circumtropical, commonly found in Chile, South Africa, and Australasia, while <a class="taxon-link" href="/accounts/Peripatopsidae/">peripatopsids</a> are circumaustral, found in Southeast Asia, west equatorial Africa, northern South America, Central America, Mexico, and the Antilles. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Biogeographic Regions</li> <li> <a class="gloss" href="#20020914235803">nearctic</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> <li> <a class="gloss" href="#20020915001330">palearctic</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> <li> <a class="gloss" href="#20020915001348">oriental</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> <li> <a class="gloss" href="#20020916134510">ethiopian</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> <li> <a class="gloss" href="#20020915000403">neotropical</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> <li> <a class="gloss" href="#20020916135737">australian</a> <ul> <li> <a class="gloss" href="#20020904145365">native</a> </li> </ul> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Other Geographic Terms</li> <li> <a class="gloss" href="#200304045530">holarctic</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="habitat">Habitat</h3> <p audience="advanced intermediate">All currently living <span class="taxon-link">onychophoran</span> species are terrestrial, although the fossil record shows they were likely aquatic at some point, the shift to land probably took place during the Ordovician period. They are nocturnal and photonegative, living primarily in dark, moist microhabitats such as forest litter and soil, within bromeliads, or in rotten logs. A few species are cave dwelling or live in drier woodlands and grasslands. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Habitat Regions</li> <li> <a class="gloss" href="#20020904145595">temperate</a> </li> <li> <a class="gloss" href="#20020904145598">tropical</a> </li> <li> <a class="gloss" href="#20020904145794">terrestrial</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Terrestrial Biomes</li> <li> <a class="gloss" href="#20020904145599::20020904145583::20020904145682">savanna or grassland</a> </li> <li> <a class="gloss" href="#20020904145828">forest</a> </li> <li> <a class="gloss" href="#20020904145487">rainforest</a> </li> <li> <a class="gloss" href="#20020904145677">scrub forest</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="taxonomic_history">Systematic and Taxonomic History</h3> <p audience="advanced intermediate">Early researchers considered <span class="taxon-link">onychophorans</span> to be a link between <a class="taxon-link" href="/accounts/Annelida/">annelids</a> and <a class="taxon-link" href="/accounts/Arthropoda/">arthropods</a>, as they share characteristics with both phyla. Recent molecular research has suggested that onychophorans are actually modified arthropods, supporting the shared morphological characteristics between these phyla, including a chitinous cuticle, as well as features of their respiratory system and embryogenesis. Onychophorans and arthropods also share an evolutionary relationship with phylum <a class="taxon-link rank-unspecified" href="/accounts/Tardigrada/">Tardigrada</a>, and together form the unranked taxon <span class="taxon-name">Panarthropoda</span>. This clade belongs to superphylum <a class="taxon-link rank-unspecified" href="/accounts/Ecdysozoa/">Ecdysozoa</a>, which contains other molting invertebrates, such as <a class="taxon-link" href="/accounts/Nematoda/">nematodes</a>, <a class="taxon-link" href="/accounts/Kinorhyncha/">kinorhynchs</a>, and <a class="taxon-link" href="/accounts/Loricifera/">loriciferans</a>, but the evolutionary relationships between these larger groups are still the subject of active debate. As relatively poorly studied organisms, research on the evolutionary relationships within the phylum is sparse, although the monophyly of the phylum and its two families has consistently been strongly supported. <span class="citations"> (<a href="#D6C0F894-7DF1-11E2-A712-002500F14F28" class="citation">Ballard, et al., 1992</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#6C811497-BC17-11E2-93C9-002500F14F28" class="citation">Podsiadlowski, et al., 2008</a>; <a href="#EB512FA8-7DFF-11E2-878F-002500F14F28" class="citation">Telford, et al., 2008</a>)</span></p> <ul class="aside block-grid donthyphenate one-up"> <li> <dl> <dt>Synapomorphies</dt> <dd> <ul> <li>slime papillae and associated secretions</li> <li>mandibles of the second body segment</li> <li>extensively cross-linked nerve strands extending along the underside of body segments</li> <li>unique tracheal morphology</li> </ul> </dd> </dl> </li> </ul> </section> <section class="hyphenate"> <h3 id="physical_description">Physical Description</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> range from 5 mm to 15 cm in length, with homonomous bodies and small heads. The head houses a pair of annulated, fleshy antennae and a pair of small eyes at their bases, which are direct, with large, chitinous lenses and a developed retinal layer; a pair of jaws surrounded by circular lips; and a pair of fleshy oral papillae, also known as slime papillae. These animals are covered in a thin, flexible, permeable, chitinous cuticle, which overlays a thin epidermis. The cuticle is characteristically covered in tubercles or papillae with sensilla, arranged in rings or bands around the trunk and appendages. These protrusions are covered in scales, giving the animals a velvety appearance that gives rise to their common name. Under the epidermis, onychophorans have a dermis of connective tissue and layers of circular, diagonal and longitudinal muscles. These animals have smooth and striated muscle tissue and their hemocoels are partitioned into sinuses; the coelom is restricted to the gonodal cavities. They have hemocoelic, hydrostatic skeletons. Onychophorans are generally blue, black, green or orange. Onychophorans have 13 to 43 pairs of lobopodal walking legs; <a class="taxon-link" href="/accounts/Peripatopsidae/">peripatopsid</a> species have a fixed number of legs, while <a class="taxon-link" href="/accounts/Peripatidae/">peripatid</a> species may have a variable number of legs. The conical legs are filled with hemocoelomic fluid and have extrinsic muscle extensions. Each leg has a multi-spined terminal claw and a distal transverse pad on which it rests while walking. Onychophorans are typically sexually dimorphic, females are larger than males. In species where the number of leg pairs are variable, females also have more legs. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>; <a href="#F044430A-9301-11E2-8DD9-002500F14F28" class="citation">Waggoner, 1999</a>)</span></p> <p audience="advanced intermediate">The mouth opens into a chitin-lined pharynx and esophagus (foregut), which lead to a long, straight intestine where most digestion and absorption occurs. The hindgut typically loops over the intestine before it leads to the anus located on the last body segment (terminally or ventrally). Each leg-bearing body segment also has a pair of nephridia with associated nephridiopores near the base of each leg, with the exception of the fourth and fifth legs, where nephridiopores are located distally on transverse pads, and the segment where the gonopores are located, which has no nephridia. Nephridia are connected internally to a sacculus (coelomic end sac) which leads to a nephridioduct, together; the sacculus and nephridioduct are called the segmental gland. Each nephridioduct has a contractile bladder that opens via the nephridiopore. Some species have eversible sacs via hemocoelic pressure, or vesicles opening near the nephridiopores as well, which may help to take up moisture. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#C19CBE97-BC18-11E2-97F5-002500F14F28" class="citation">Ruppert, et al., 2004</a>)</span></p> <p audience="advanced intermediate">Velvet worms also have well-developed circulatory systems, similar to arthropods. The heart is tubular, opens at both ends, and lies in a pericardial sinus. The blood, which is colorless and has no oxygen binding capabilities, enters the heart through lateral ostia and leaves anteriorly, flowing throughout the hemocoel within the body’s sinuses. Hemal channels are also located under the cuticle, between the circular muscle and oblique muscle layers, and are likely important as part of the hydrostatic skeleton. Gas exchange occurs via diffusion across the body wall and through tracheae, which open through small spiracles located between the bands of body tubercles. Tracheal units are small and only provide gases to the tissues immediately adjacent to them. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#C19CBE97-BC18-11E2-97F5-002500F14F28" class="citation">Ruppert, et al., 2004</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Other Physical Features</li> <li> <a class="gloss" href="#20020916131519">ectothermic</a> </li> <li> <a class="gloss" href="#20020916125902">heterothermic</a> </li> <li> <a class="gloss" href="#20020904145642">bilateral symmetry</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Sexual Dimorphism</li> <li> <span>female larger</span> </li> <li> <span>sexes shaped differently</span> </li> </ul> </section> <section class="hyphenate"> <h3 id="development">Development</h3> <p audience="advanced intermediate">Onychophorans may be oviparous, viviparous or ovoviviparous. In oviparous species, large, oval, yolky eggs (up to 2 mm in diameter), with chitinous shells are produced and laid through an ovipositor. Early, superficial, intralecithal cleavage occurs, due to the large size of the yolk, followed by the development of a germinal disc. Ovoviviparous species may produce large yolky eggs (up to 1.5 mm in diameter), or smaller eggs (0.5 mm in diameter) with little to no yolk and thin membranes. Early cleavage of ovoviviparous embryos is intralecithal in those eggs with yolks; development has not been described well for non-yolky ovoviviparous eggs. Viviparous species produce small, spherical, non-yolky eggs and may or may not have placentas, when no placenta is present, eggs are even smaller and cleavage is total and equal. Vivipary is the most commonly observed reproductive strategy for this phylum. Onychophorans develop directly and hatch, or are born as juveniles with developed body segments and organs. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#0875200F-9305-11E2-833E-002500F14F28" class="citation">Eriksson and Tait, 2012</a>)</span></p> </section> <section class="hyphenate"> <h3 id="reproduction">Reproduction</h3> <p audience="advanced intermediate">Mating behavior has seldom been observed and seems to vary widely amongst species. Both dermal and vaginal inseminations are known. Males of some species (<a class="taxon-link rank-species" href="/accounts/Florelliceps_stutchburyae/">Florelliceps stutchburyae</a>, <a class="taxon-link rank-species" href="/accounts/Planipapillus_annae/">Planipapillus annae</a>) have specialized head structures with which they transfer a spermatophore directly to a female's genital opening; during the transfer, a male is held in place by the female's lodopod claws. Others deposit spermatophores on females’ bodies, triggering a breakdown of integument so that the sperm may pass into the hemocoelic fluid, through which it travels to the ovaries. Females of some species have seminal receptacles, which are enlargements of the uterus. Although the mating systems of most onychophorans have not been determined, polygyny is most likely, as vivipary is the most common reproductive strategy. <span class="citations"> (<a href="#26A3C73A-9308-11E2-ADC7-002500F14F28" class="citation">"Velvet Worm", 2010</a>; <a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#BB043914-7DFF-11E2-89C3-002500F14F28" class="citation">Tait and Norman, 2001</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Mating System</li> <li> <a class="gloss" href="#20020904145840">polygynous</a> </li> </ul> <p audience="advanced intermediate">Onychophorans are dioecious, with the exception of one known parthenogenetic species (<span rank="Species" class="taxon-name rank-species">Epiperipatus imthurni</span>), and sexually dimorphic, females are larger than males, and potentially have more legs. Males have a pair of elongated testes, their sperm ducts join into a single tube, where spermatophores up to 1 mm in length are formed. The single sperm tube opens in a posteroventral gonopore. Females have a pair of ovaries that are mostly fused and located in the posterior region of their bodies, connecting to gonoducts that fuse into a uterus, also opening through a posteroventral gonopore. Fertilization is internal. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#FD229DBA-9309-11E2-9C16-002500F14F28" class="citation">Read, 1988</a>)</span></p> <p audience="advanced intermediate"><a class="taxon-link" href="/accounts/Peripatopsidae/">Peripatopsids</a> may be oviparous, oviviparous or viviparous and produce 6 to 23 offspring a year, while <a class="taxon-link" href="/accounts/Peripatidae/">peripatids</a> are viviparous and only produce 1 to 8 offspring per year. Peripatopsid eggs develop within 6 to 17 months, or are born after 11 to 13 months of gestation; the gestation period for peripatids is approximately 1 year. Some onychophorans breed once a year, while others may breed multiple times in a year. Gestation in viviparous species can be up to 15 months, a female may have embryos of varied ages developing in her uterus at any given time. <span class="citations"> (<a href="#0875200F-9305-11E2-833E-002500F14F28" class="citation">Eriksson and Tait, 2012</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Key Reproductive Features</li> <li> <a class="gloss" href="#20020904145554">iteroparous</a> </li> <li> <a class="gloss" href="#20020904145584">seasonal breeding</a> </li> <li> <a class="gloss" href="#20020904145698">year-round breeding</a> </li> <li> <span>gonochoric/gonochoristic/dioecious (sexes separate)</span> </li> <li> <a class="gloss" href="#20020904145768">parthenogenic</a> </li> <li> <a class="gloss" href="#20020904145786">sexual</a> </li> <li> <a class="gloss" href="#20020904145314">asexual</a> </li> <li> <a class="gloss" href="#20020904145546">fertilization</a> <ul> <li> <a class="gloss" href="#20020904145427">internal</a> </li> </ul> </li> <li> <a class="gloss" href="#20020904145695">viviparous</a> </li> <li> <a class="gloss" href="#20020904145610">ovoviviparous</a> </li> <li> <a class="gloss" href="#20020904145572">oviparous</a> </li> </ul> <p audience="advanced intermediate">Beyond gamete production, the parental investment exhibited by onychophorans is unknown. In captivity, some species have been observed in adult-newborn groups, in the wild, groupings of young individuals are often found. <span class="citations"> (<a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Parental Investment</li> <li> <span>no parental involvement</span> </li> <li> <span>pre-hatching/birth</span> <ul> <li> <span>provisioning</span> <ul> <li> <span>female</span> </li> </ul> </li> </ul> </li> </ul> </section> <section class="hyphenate"> <h3 id="lifespan_longevity">Lifespan/Longevity</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> typically live several years; females are not known to reproduce until reaching at least 1.4 years of age. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> </section> <section class="hyphenate"> <h3 id="behavior">Behavior</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> are typically solitary; they are also photonegative and nocturnal. They are most active in humid and damp environments; activity greatly decreases during dry periods. Onychophorans move using their lopodal legs and extending and contracting their bodies using hydrostatic forces. Movement is from front to back, in a wave; when an anterior segment elongates, their legs lift and move forward and, when it contracts again, anterior legs and segments are pulled forward. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Key Behaviors</li> <li> <span>terricolous</span> </li> <li> <a class="gloss" href="#20020904145503">nocturnal</a> </li> <li> <a class="gloss" href="#20020904145472">motile</a> </li> <li> <a class="gloss" href="#20020904145585">sedentary</a> </li> <li> <a class="gloss" href="#20020904145381">solitary</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="communication">Communication and Perception</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> have large, bilobed cerebral ganglia dorsal to the pharynx, which are attached to a pair of ventral nerve cords (via transverse segmental commissures) and supply nerves to the head elements, also giving rise to the paired nerves of the appendages and body wall. The tubercles and papillae on their body surfaces are covered in sensilla. They have a small dorsolateral eye at the base of each antenna, which are direct, with a chitinous lens and well-developed retinal layer. There is evidence that males of some onychophoran species secrete a pheromone from papillae on their legs, attracting both males and females in order to disperse and colonize new habitats such as rotting logs. <span class="citations"> (<a href="#EBF19138-930E-11E2-BE27-002500F14F28" class="citation">Barclay, et al., 2000</a>; <a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#C19CBE97-BC18-11E2-97F5-002500F14F28" class="citation">Ruppert, et al., 2004</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Communication Channels</li> <li> <a class="gloss" href="#20020904145694">visual</a> </li> <li> <a class="gloss" href="#20020904145500">tactile</a> </li> <li> <a class="gloss" href="#20020904145606">chemical</a> </li> </ul> <ul class="keywords donthyphenate "> <li class="keywords-header">Other Communication Modes</li> <li> <a class="gloss" href="#20020904145769">pheromones</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Perception Channels</li> <li> <a class="gloss" href="#20020904145694">visual</a> </li> <li> <a class="gloss" href="#20020904145500">tactile</a> </li> <li> <a class="gloss" href="#20020904145606">chemical</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="food_habits">Food Habits</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> are carnivorous, typically feeding on small invertebrates such as beetles, termites, and other insects, as well as snails and worms. They sometimes pursue their prey into small spaces. Onychophorans produce a powerful adhesive in their slime glands, which open at the end of their oral papillae; they can shoot this substance up to 30 cm to trap prey. Onychophorans use their jaws to grasp and cut prey and inject salivary secretions, which are produced by paired salivary glands and delivered along a median dorsal groove on the jaws. These secretions begin to digest the prey so the semi-liquidized tissues can be sucked into the mouth. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Primary Diet</li> <li> <a class="gloss" href="#20020904145419">carnivore</a> <ul> <li> <a class="gloss" href="#20020904145711">insectivore</a> </li> <li> <span>eats non-insect arthropods</span> </li> <li> <a class="gloss" href="#20020914202902">molluscivore</a> </li> </ul> </li> </ul> </section> <section class="hyphenate"> <h3 id="predation">Predation</h3> <p audience="advanced intermediate">The adhesive substance used by <span class="taxon-link">onychophorans</span> to ensnare prey may also be used to evade predators. Likewise, the lighter coloration of juveniles may be a type of camouflage. Their predators include birds, centipedes, and spiders, as well as Hemprichi's coral snakes, which are believed to feed almost exclusively on onychophorans. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>; <a href="#F585C91C-9313-11E2-B470-002500F14F28" class="citation">Monge-Nájera, et al., 1993</a>; <a href="#FA8A063D-92FD-11E2-A1C5-002500F14F28" class="citation">Shapiro, 2012</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Anti-predator Adaptations</li> <li> <a class="gloss" href="#20020913232730">cryptic</a> </li> </ul> <ul class="aside block-grid donthyphenate one-up"> <li> <dl> <dt>Known Predators</dt> <dd> <ul> <li>Hemprichi's coral snakes (<a class="taxon-link rank-species" href="/accounts/Micrurus_hemprichii/">Micrurus hemprichii</a>)</li> <li>clay-colored thrushes (<a class="taxon-link rank-species" href="/accounts/Turdus_grayi/">Turdus grayi</a>)</li> <li>centipedes (Class <a class="taxon-link rank-class" href="/accounts/Chilopoda/">Chilopoda</a>, Phylum <a class="taxon-link rank-unspecified" href="/accounts/Arthropoda/">Arthropoda</a>)</li> <li>spiders (Order <a class="taxon-link rank-order" href="/accounts/Araneae/">Araneae</a>, Phylum <a class="taxon-link rank-unspecified" href="/accounts/Arthropoda/">Arthropoda</a>)</li> </ul> </dd> </dl> </li> </ul> </section> <section class="hyphenate"> <h3 id="ecosystem_roles">Ecosystem Roles</h3> <p audience="advanced intermediate">The regular molting cycles of <span class="taxon-link">onychophorans</span> may be, in part, an anti-ectoparasite mechanism. Phoretic mites have been reported on some onychophorans, as have unspecified bacteria reproducing in their mid-line cuticular pits. <span class="citations"> (<a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> <div class="note"> <strong>Commensal/Parasitic Species</strong> <br /> <ul> <li>mites (Class <a class="taxon-link rank-class" href="/accounts/Arachnida/">Arachnida</a>, Phylum <a class="taxon-link rank-unspecified" href="/accounts/Arthropoda/">Arthropoda</a>)</li> </ul> </div> </section> <section class="hyphenate"> <h3 id="economic_importance_positive">Economic Importance for Humans: Positive</h3> <p audience="advanced intermediate">Outside of scientific research, there are no known positive effects of <span class="taxon-link">onychophorans</span> on humans. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Positive Impacts</li> <li> <span>research and education</span> </li> </ul> </section> <section class="hyphenate"> <h3 id="economic_importance_negative">Economic Importance for Humans: Negative</h3> <p audience="advanced intermediate">There are no known adverse effects of <span class="taxon-link">onychophorans</span> on humans. <span class="citations"> (<a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>)</span></p> </section> <section class="hyphenate"> <h3 id="conservation_status">Conservation Status</h3> <p audience="advanced intermediate"><span class="taxon-link">Onychophorans</span> are not considered threatened or in danger of extinction. <span class="citations"> (<a href="#26A3C73A-9308-11E2-ADC7-002500F14F28" class="citation">"Velvet Worm", 2010</a>)</span></p> <ul class="aside block-grid donthyphenate one-up"> <li> <dl> <dt>IUCN Red List <a href="http://www.iucnredlist.org/">[Link]</a></dt> <dd>Not Evaluated</dd> </dl> </li> </ul> </section> <section class="hyphenate"> <h3 id="comments">Other Comments</h3> <p audience="advanced intermediate">This phylum was part of the early Cambrian marine diversification and has an extensive fossil record throughout North America and Asia. Beyond their move from water to land, little has changed for these species over the last 530 million years. <span class="citations"> (<a href="#A028EDA6-BC1B-11E2-9F4E-002500F14F28" class="citation">Bergstrom and Hou, 2001</a>; <a href="#2DAACB42-7DF2-11E2-82BF-002500F14F28" class="citation">Brusca and Brusca, 2003</a>; <a href="#E19340CC-92FA-11E2-8916-002500F14F28" class="citation">Monge-Nájera, 1995</a>)</span></p> </section> <section class="hyphenate"> <h3 id="contributors">Contributors</h3> <p>Jeremy Wright (author), University of Michigan-Ann Arbor, Leila Siciliano Martina (editor), Animal Diversity Web Staff. </p> </section> <section class="offscreen"> <h3 id="glossary">Glossary</h3> <div id="20020916135737"> <dl> <dt>Australian</dt> <dd> <p>Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020916134510"> <dl> <dt>Ethiopian</dt> <dd> <p>living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020914235803"> <dl> <dt>Nearctic</dt> <dd> <p>living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020915000403"> <dl> <dt>Neotropical</dt> <dd> <p>living in the southern part of the New World. In other words, Central and South America.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020915001330"> <dl> <dt>Palearctic</dt> <dd> <p>living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020904145314"> <dl> <dt>asexual</dt> <dd> <p>reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents</p> </dd> </dl> </div> <div id="20020904145642"> <dl> <dt>bilateral symmetry</dt> <dd> <p>having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.</p> </dd> </dl> </div> <div id="20020904145419"> <dl> <dt>carnivore</dt> <dd> <p>an animal that mainly eats meat</p> </dd> </dl> </div> <div id="20020904145606"> <dl> <dt>chemical</dt> <dd> <p>uses smells or other chemicals to communicate</p> </dd> </dl> </div> <div id="20020913232730"> <dl> <dt>cryptic</dt> <dd> <p>having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.</p> </dd> </dl> </div> <div id="20020916131519"> <dl> <dt>ectothermic</dt> <dd> <p>animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature</p> </dd> </dl> </div> <div id="20020904145546"> <dl> <dt>fertilization</dt> <dd> <p>union of egg and spermatozoan</p> </dd> </dl> </div> <div id="20020904145828"> <dl> <dt>forest</dt> <dd> <p>forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.</p> </dd> </dl> </div> <div id="20020916125902"> <dl> <dt>heterothermic</dt> <dd> <p>having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.</p> </dd> </dl> </div> <div id="200304045530"> <dl> <dt>holarctic</dt> <dd> <p>a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> <p>Found in northern North America and northern Europe or Asia.</p> </dd> </dl> </div> <div id="20020904145711"> <dl> <dt>insectivore</dt> <dd> <p>An animal that eats mainly insects or spiders.</p> </dd> </dl> </div> <div id="20020904145427"> <dl> <dt>internal fertilization</dt> <dd> <p>fertilization takes place within the female's body</p> </dd> </dl> </div> <div id="20020904145554"> <dl> <dt>iteroparous</dt> <dd> <p>offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).</p> </dd> </dl> </div> <div id="20020914202902"> <dl> <dt>molluscivore</dt> <dd> <p>eats mollusks, members of Phylum Mollusca</p> </dd> </dl> </div> <div id="20020904145472"> <dl> <dt>motile</dt> <dd> <p>having the capacity to move from one place to another.</p> </dd> </dl> </div> <div id="20020904145365"> <dl> <dt>native range</dt> <dd> <p>the area in which the animal is naturally found, the region in which it is endemic.</p> </dd> </dl> </div> <div id="20020904145503"> <dl> <dt>nocturnal</dt> <dd> <p>active during the night</p> </dd> </dl> </div> <div id="20020915001348"> <dl> <dt>oriental</dt> <dd> <p>found in the oriental region of the world. In other words, India and southeast Asia.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020904145572"> <dl> <dt>oviparous</dt> <dd> <p>reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.</p> </dd> </dl> </div> <div id="20020904145610"> <dl> <dt>ovoviviparous</dt> <dd> <p>reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.</p> </dd> </dl> </div> <div id="20020904145768"> <dl> <dt>parthenogenic</dt> <dd> <p>development takes place in an unfertilized egg</p> </dd> </dl> </div> <div id="20020904145769"> <dl> <dt>pheromones</dt> <dd> <p>chemicals released into air or water that are detected by and responded to by other animals of the same species</p> </dd> </dl> </div> <div id="20020904145840"> <dl> <dt>polygynous</dt> <dd> <p>having more than one female as a mate at one time</p> </dd> </dl> </div> <div id="20020904145487"> <dl> <dt>rainforest</dt> <dd> <p>rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.</p> </dd> </dl> </div> <div id="20020904145677"> <dl> <dt>scrub forest</dt> <dd> <p>scrub forests develop in areas that experience dry seasons.</p> </dd> </dl> </div> <div id="20020904145584"> <dl> <dt>seasonal breeding</dt> <dd> <p>breeding is confined to a particular season</p> </dd> </dl> </div> <div id="20020904145585"> <dl> <dt>sedentary</dt> <dd> <p>remains in the same area</p> </dd> </dl> </div> <div id="20020904145786"> <dl> <dt>sexual</dt> <dd> <p>reproduction that includes combining the genetic contribution of two individuals, a male and a female</p> </dd> </dl> </div> <div id="20020904145381"> <dl> <dt>solitary</dt> <dd> <p>lives alone</p> </dd> </dl> </div> <div id="20020904145500"> <dl> <dt>tactile</dt> <dd> <p>uses touch to communicate</p> </dd> </dl> </div> <div id="20020904145595"> <dl> <dt>temperate</dt> <dd> <p>that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).</p> </dd> </dl> </div> <div id="20020904145794"> <dl> <dt>terrestrial</dt> <dd> <p>Living on the ground.</p> </dd> </dl> </div> <div id="20020904145598"> <dl> <dt>tropical</dt> <dd> <p>the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.</p> </dd> </dl> </div> <div id="20020904145599::20020904145583::20020904145682"> <dl> <dt>tropical savanna and grassland</dt> <dd> <p>A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.</p> </dd> <dt>savanna</dt> <dd> <p>A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.</p> </dd> <dt>temperate grassland</dt> <dd> <p>A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.</p> </dd> </dl> </div> <div id="20020904145694"> <dl> <dt>visual</dt> <dd> <p>uses sight to communicate</p> </dd> </dl> </div> <div id="20020904145695"> <dl> <dt>viviparous</dt> <dd> <p>reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.</p> </dd> </dl> </div> <div id="20020904145698"> <dl> <dt>year-round breeding</dt> <dd> <p>breeding takes place throughout the year</p> </dd> </dl> </div> </section> <section class="hyphenate"> <h3 id="references">References</h3> <p id="26A3C73A-9308-11E2-ADC7-002500F14F28">2010. "Velvet Worm" (On-line). Australian Museum. Accessed March 22, 2013 at <tt><a href="http://australianmuseum.net.au/Velvet-worm">http://australianmuseum.net.au/Velvet-worm</a></tt>. </p> <p id="D6C0F894-7DF1-11E2-A712-002500F14F28">Ballard, J., G. Olsen, D. Faith, W. Odgers, D. Rowell, P. Atkinson. 1992. Evidence from 12S ribosomal RNA sequences that onychophorans are modified arthropods. <span style="font-style: italic">Science</span>, 258: 1345-1348. </p> <p id="EBF19138-930E-11E2-BE27-002500F14F28">Barclay, S., D. Rowell, J. Ash. 2000. Pheromonally mediated colonization patterns in the velvet worm <a class="taxon-link rank-species" href="/accounts/Euperipatoides_rowelli/">Euperipatoides rowelli</a> (<span class="taxon-link rank-unspecified">Onychophora</span>). <span style="font-style: italic">Journal of Zoology</span>, 250/4: 437-446. Accessed March 22, 2013 at <tt><a href="http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=40803">http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=40803</a></tt>. </p> <p id="A028EDA6-BC1B-11E2-9F4E-002500F14F28">Bergstrom, J., X. Hou. 2001. Cambrian <span class="taxon-link rank-unspecified">Onychophora</span> or Xenusians. <span style="font-style: italic">Zoologischer Anzeiger</span>, 240: 237-245. </p> <p id="2DAACB42-7DF2-11E2-82BF-002500F14F28">Brusca, R., G. Brusca. 2003. <span style="font-style: italic">Invertebrates (2nd Edition)</span>. Sunderland, MA: Sinauer Associates. </p> <p id="0875200F-9305-11E2-833E-002500F14F28">Eriksson, B., N. Tait. 2012. Early development in the velvet worm <a class="taxon-link rank-species" href="/accounts/Euperipatoides_kanangrensis/">Euperipatoides kanangrensis</a> Reid 1996 (<span class="taxon-link rank-unspecified">Onychophora</span>: <a class="taxon-link rank-family" href="/accounts/Peripatopsidae/">Peripatopsidae</a>). <span style="font-style: italic">Arthropod Structure and Development</span>, 41/5: 483-493. Accessed March 22, 2013 at <tt><a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437555/">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437555/</a></tt>. </p> <p id="8BF809B5-7DFF-11E2-8841-002500F14F28">Leishman, M., M. Eldridge. 1990. Life history characteristics of two sympatric onychophoran species from the Blue Mountains, New South Wales. <span style="font-style: italic">Proceedings of the Linnaean Society of New South Wales</span>, 112: 173-185. Accessed March 22, 2013 at <tt><a href="http://biostor.org/reference/68211">http://biostor.org/reference/68211</a></tt>. </p> <p id="E19340CC-92FA-11E2-8916-002500F14F28">Monge-Nájera, J. 1995. Phylogeny, biogeography and reproductive trends in the <span class="taxon-link rank-unspecified">Onychophora</span>. Pp. 21-60 in M Walker, D Norman, eds. <span style="font-style: italic"><span class="taxon-link rank-unspecified">Onychophora</span>: Past and present</span>, Vol. 114. London, England: Academic Press. Accessed March 22, 2013 at <tt><a href="http://www.tropinature.com/biogeo/papers/Phylogeny.pdf">http://www.tropinature.com/biogeo/papers/Phylogeny.pdf</a></tt>. </p> <p id="F585C91C-9313-11E2-B470-002500F14F28">Monge-Nájera, J., Z. Barrientos, F. Aguilar. 1993. Behavior of <a class="taxon-link rank-species" href="/accounts/Epiperipatus_biolleyi/">Epiperipatus biolleyi</a> (<span class="taxon-link rank-unspecified">Onychophora</span>: <a class="taxon-link rank-family" href="/accounts/Peripatidae/">Peripatidae</a>) under laboratory conditions. <span style="font-style: italic">Revista de Biologica Tropical</span>, 41/3: 689-696. Accessed March 22, 2013 at <tt><a href="http://www.tropinature.com/cvitjmn/publications/artcient/onicof/behavior.pdf">http://www.tropinature.com/cvitjmn/publications/artcient/onicof/behavior.pdf</a></tt>. </p> <p id="6C811497-BC17-11E2-93C9-002500F14F28">Podsiadlowski, L., A. Braband, G. Mayer. 2008. The complete mitochondrial genome of the onychophoran <a class="taxon-link rank-species" href="/accounts/Epiperipatus_biolleyi/">Epiperipatus biolleyi</a> reveals a unique transfer RNA set and provides further support for the ecdysozoa hypothesis. <span style="font-style: italic">Molecular Biology and Evolution</span>, 25/1: 42-51. </p> <p id="FD229DBA-9309-11E2-9C16-002500F14F28">Read, V. 1988. The <span class="taxon-link rank-unspecified">Onychophora</span> of Trinidad, Tobago and the Lesser Antilles. <span style="font-style: italic">Zoological Journal of the Linnaean Society</span>, 93/3: 225-257. Accessed March 22, 2013 at <tt><a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1988.tb01362.x/abstract">http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1988.tb01362.x/abstract</a></tt>. </p> <p id="C19CBE97-BC18-11E2-97F5-002500F14F28">Ruppert, E., R. Fox, R. Barnes. 2004. <span style="font-style: italic">Invertebrate zoology: A functional evolutionary approach (7th edition)</span>. Belmont, CA: Thomson-Brooks/Cole. </p> <p id="FA8A063D-92FD-11E2-A1C5-002500F14F28">Shapiro, L. 2012. "<span class="taxon-link rank-unspecified">Onychophora</span>: Velvet Worms" (On-line). Encyclopedia of Life. Accessed March 22, 2013 at <tt><a href="http://eol.org/pages/6927/overview">http://eol.org/pages/6927/overview</a></tt>. </p> <p id="BB043914-7DFF-11E2-89C3-002500F14F28">Tait, N., J. Norman. 2001. Novel mating behaviour in <a class="taxon-link rank-species" href="/accounts/Florelliceps_stutchburyae/">Florelliceps stutchburyae</a> gen. nov., sp. nov. (<span class="taxon-link rank-unspecified">Onychophora</span>: <a class="taxon-link rank-family" href="/accounts/Peripatopsidae/">Peripatopsidae</a>) from Australia. <span style="font-style: italic">Journal of Zoology</span>, 253/3: 301-308. </p> <p id="EB512FA8-7DFF-11E2-878F-002500F14F28">Telford, M., S. Bourlat, A. Economou, D. Papillon, O. Rota-Stabelli. 2008. The evolution of the <a class="taxon-link rank-unspecified" href="/accounts/Ecdysozoa/">Ecdysozoa</a>. <span style="font-style: italic">Proceedings of the Royal Society B: Biological Sciences</span>, 363: 1529-1537. Accessed March 22, 2013 at <tt><a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614232/">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614232/</a></tt>. </p> <p id="F044430A-9301-11E2-8DD9-002500F14F28">Waggoner, B. 1999. "Introduction to the <span class="taxon-link rank-unspecified">Onychophora</span>" (On-line). University of California Museum of Paleontology. Accessed March 22, 2013 at <tt><a href="http://www.ucmp.berkeley.edu/onychoph/onychophora.html">http://www.ucmp.berkeley.edu/onychoph/onychophora.html</a></tt>. </p> <p id="228415AB-7E00-11E2-9D98-002500F14F28">Zhang, Z. 2011. Animal biodiversity: an introduction to higher-level classification and taxonomic richness. <span style="font-style: italic">Zootaxa</span>, 3148: 7-12. </p> </section> </div> </div> <div class="span2_5 right sidebar"> <div class="well" id="pocket-guide-link"> <a href="https://itunes.apple.com/us/app/adw-pocket-guide/id916179421?mt=8" target="_blank"><i class="icon-download icon-white" style="vertical-align: bottom"></i> ADW Pocket Guides on the iOS App Store! </a> <p>The Animal Diversity Web team is excited to announce ADW Pocket Guides!</p> <p> <a href="/news/5009059054038197651/">Read more...</a> </p> </div> <h2 class="offscreen">Search</h2> <div id="site-search"> <form action="/search" method="GET"> <label for="q" class="offscreen">Enter search text</label> <input value="" id="q" name="q" class="span12" size="15" type="text" placeholder="Search ADW" /> <button class="btn"> <i class="icon-zoom-in"></i> <span class="offscreen">Search</span> </button> <p style="max-height: 35px"> 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ADW: Onychophora: INFORMATION