| Onychophora |
Velvet worm | | Scientific classification | | Kingdom: | Animalia
| | Phylum: | Onychophora
Grube, 1853 | |
Global range of Onychophora: Peripatidae in green, Peripatopsidae in blue | | Extant families | | Peripatidae
Peripatopsidae Image File history File linksMetadata 31-Velvet_Worm. ...
Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ...
For other uses, see Animal (disambiguation). ...
Image File history File links Size of this preview: 800 × 370 pixelsFull resolution (1357 × 628 pixel, file size: 41 KB, MIME type: image/png) Distribution of the Onychophorans Peripatida (green) and Peripatopsidae (blue), made by de:Benutzer:Achim Raschka. ...
The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ...
| Onychophora, the velvet worms (occasionally called walking worms or spitting worms), are segmented, caterpillar-like, terrestrial animals somewhat resembling both arthropods and annelid worms. They are generally regarded either as a class of arthropods or as a separate phylum (in which case they are the only animal phylum to include no known marine species). About 200 modern species are known separated into two families, with 10 genera — Peripatidae, found in many tropical and subtropical regions worldwide including Mexico, Central America, South America, and Africa, and Peripatopsidae, found in Chile, South Africa, Australia and New Zealand. Modern species are fairly small; at least one species reaches lengths of 20 cm (8 inches). The best known modern form is Peripatus which was described by Guilding in 1825. Caterpillar of the Emperor Gum Moth A caterpillar is the larval form of a member of the order Lepidoptera (the insect order comprising butterflies and moths). ...
Terrestrial animals are animals that live predominantly or entirely on land, as compared with aquatic animals, which live predominantly or entirely in the water (e. ...
Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ...
Classes and subclasses Class Polychaeta (paraphyletic?) Class Clitellata Oligochaeta - Earthworms and others Acanthobdellida Branchiobdellida Hirudinea - Leeches Class Myzostomida Class Archiannelida (polyphyletic) Class Echiura *Some authors consider the subclasses under Clitellata to be classes The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about...
A class is the rank in the scientific classification of organisms in biology below Phylum and above Order. ...
Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ...
Phylum (plural: phyla) is a taxon used in the classification of animals, adopted from the Greek phylai the clan-based voting groups in Greek city-states. ...
The hierarchy of scientific classification. ...
The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ...
For other uses, see Genus (disambiguation). ...
The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ...
Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ...
For other uses, see Central America (disambiguation). ...
South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ...
A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ...
A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ...
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
Peripatus is a genus of Onychophora. ...
Opening of the Stockton and Darlington Railway 1825 (MDCCCXXV) was a common year starting on Saturday (see link for calendar). ...
Description
Onychophores are apparently descended from some segmented form but have lost their overt segmentation except for the head which is composed of three segments. There are two antennae on the first head segment and usually a pair of eyes. The second head segment has a mouth. Unlike arthropods, the animal does not have a stiff exoskeleton. Their skin (cuticle) is covered with fine hair (papillae) giving a velvet-like feel and accounting for their popular name of "velvet worms". The cuticle is shed periodically to allow growth. Although the body has several dozen repeated leg pairs, it is not actually segmented like annelids. The true coelom, like that of arthropods, is restricted almost entirely to the gonadal cavities. The hemocoel is also arthropod-like, being partitioned into sinuses, including a dorsal pericardial sinus. The entire structure is supported by blood pumped by a heart. Legs are tipped by chitinous claws and walking pads used on smooth surfaces. Onychophores breathe through passages in the skin called trachea which are always open. As a result, all known species require a humid environment to avoid desiccation. Insects display a wide variety of antennal shapes. ...
Eponychium is the anatomical term for the human cuticle In biology, the term cuticle or cuticula is given to to a variety of tough but flexible, non-mineral outer coverings of an organism, or part of an organism, that provide prtoection. ...
A papilla (plural: papillae) can be: A small projection, such as a nipplelike projection on the skin, at the base of a hair or the root of a feather; the base of a new tooth. ...
Velvet is a type of tufted fabric in which the cut threads are very evenly distributed, with a short dense pile, giving it its distinct feel. ...
Classes and subclasses Class Polychaeta (paraphyletic?) Class Clitellata Oligochaeta - Earthworms and others Acanthobdellida Branchiobdellida Hirudinea - Leeches Class Myzostomida Class Archiannelida (polyphyletic) Class Echiura *Some authors consider the subclasses under Clitellata to be classes The annelids, collectively called Annelida, are a large phylum of animals, comprising the segmented worms, with about...
By the broadest definition, a body cavity is any fluid filled space in a multicellular organism. ...
An open circulatory system is an arrangement of internal transport in which blood bathes the organs directly and there is no distinction between blood and interstitial fluid. ...
Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ...
The heart and lungs, from an older edition of Grays Anatomy. ...
Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ...
Many terrestrial arthropods have evolved a closed respiratory system composed of spiracles, tracheae, and tracheoles to transport metabolic gasses to and from tissue. ...
This article or section is not written in the formal tone expected of an encyclopedia article. ...
Desiccation is the state of extreme dryness, or the process of extreme drying. ...
Behaviour Modern onychophores are predators that are able to immobilize animals several times their own size with an adhesive substance that they eject from glands in their head. They can immobilize targets up to 30 cm (12 in) away, and carry a quantity of fluid of as much as 10% of their body weight. This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ...
Velvet worms have an unusual method of transferring sperm. The male onychophore attaches a sperm packet to the female. They tend to be fairly indiscriminate where on the female they attach the packet. The tissue beneath the packet dissolves and the packet melts into the female's body. The sperm swim through the hemocoel to the ovaries. Velvet worms are live-bearers, and care for their young after birth.
Evolution Onychophores are thought to be closely related to the arthropods. The structure of their brains is similar to spiders, raising the possibility that they are most closely related to arachnids, though molecular analysis contradicts this. Possible marine onychopores are known from the Lower Cambrian — Aysheaia, Hallucigenia — and possibly the late Pre-Cambrian — Xenusion. A single fossil terrestrial species, Helenodora inopinata, is known from the Pennsylvanian of Illinois, another one by the name of Cretoperipatus burmiticus from the Cretaceous of Myanmar and some Tertiary specimens are reported from Caribbean amber. Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ...
The Cambrian is a major division of the geologic timescale that begins about 542 ± 1. ...
Aysheaia pedunculata is a soft-bodied, caterpillar-shaped organism average body length of 1-6 cm. ...
Species (type) Hou & Bergström, 1995 Hallucigenia is an extinct genus of animal found as fossils in the Middle Cambrian-aged Burgess Shale formation of British Columbia, Canada. ...
The Precambrian or Cryptozoic is the period of the geologic timescale from the formation of Earth around 4500 million years before the present (BP) to the evolution of abundant macroscopic hard-shelled fossils, which marked the beginning of the Cambrian, some 542 million years BP. Remarkably little is known about...
Xenusion is a possible very primitive arthropod/onychophore known from two specimens found in glacial debris in Germany. ...
The Pennsylvanian is an epoch of the Carboniferous period lasting from roughly 325 Ma to 299 Ma (million years ago). ...
Official language(s) English[1] Capital Springfield Largest city Chicago Largest metro area Chicago Area Ranked 25th - Total 57,918 sq mi (149,998 km²) - Width 210 miles (340 km) - Length 390 miles (629 km) - % water 4. ...
Binomial name Cretoperipatus burmiticus is an extinct species of velvet worm that is known from Cretaceous amber approximately 100 million years old. ...
The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ...
Tertiary geological time interval covers roughly the time span between the demise of the non-avian dinosaurs and beginning of the most recent Ice Age, approximately 65 million to 1. ...
“West Indian†redirects here. ...
This article or section is in need of attention from an expert on the subject. ...
The similarity of these creatures to caterpillars is not purely coincidental; as with most creatures, the larval stage of moths and butterflies are thought to represent, however inconsistently, previous evolutionary stages. Arthropods are thought to have evolved from a multi-segmented animal not entirely unlike both onychophores and caterpillars. In fact, the characteristics of larval insects are part of the evidence cited to support models of insect ancestors, for example in justifying how many segments and legs such creatures are thought to have had, many of which evolved into other parts on modern insects, like antennae and mouthparts.[citation needed] Caterpillar of the Emperor Gum Moth A caterpillar is the larval form of a member of the order Lepidoptera (the insect order comprising butterflies and moths). ...
The theory of recapitulation, also called the biogenetic law or ontogeny recapitulates phylogeny, is a theory in biology which attempts to explain apparent similarities between humans and other animals. ...
Insects display a wide variety of antennal shapes. ...
The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style of feeding. ...
Classification Phylum: Onychophora Classis: Onychophorida Ordo - †Paronychophora Familiae: †Onychodictyidae - Genus: †Onychodictyon Ordo: Euonychophora Familiae: Peripatidae - Genera: †Cretoperipatus - Eoperipatus - Epiperipatus - Heteroperipatus - Macroperipatus - Mesoperipatus - Oroperipatus - Peripatus - Plicatoperipatus - Speleoperipatus - Typhloperipatus Familiae: Peripatopsidae - Genera: Acanthokara - Aethrikos - Akthinothele - Anoplokaros - Austroperipatus - Baeothele - Centrorumis - Cephalofovea - Critolaus - Dactylothele - Dystactotylos - Euperipatoides - Florelliceps - Hylonomoipos - Konothele - Lathropatus - Leuropezos - Mantonipatus - Metaperipatus - Minyplanetes - Nodocapitus - Occiperipatoides - Ooperipatellus - Ooperipatus - Opisthopatus - Paraperipatus - Paropisthopatus - Peripatoides - Peripatopsis - Phallocephale - Planipallipus - Regimitra - Ruhbergia - Sphenoparme - Symperipatus - Tasmania - Tasmanipatus - Tetrameraden - Vescerro - Wambalana Familiae: Incertae Sedis - Genus: †Helenodora
References - Richard C. Brusca & Gary J. Brusca (2003). Invertebrates. 2nd edition. Sinauer Associates, 936 pages. ISBN 0-87893-097-3.
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