Tardigrada


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Related to Tardigrada: tardigrade, Pentastomida

Tardigrada

[tär′dig·rə·də]
(invertebrate zoology)
A class of microscopic, bilaterally symmetrical invertebrates in the subphylum Malacopoda; the body consists of an anterior prostomium and five segments surrounded by a soft, nonchitinous cuticle, with four pairs of ventrolateral legs.

Tardigrada

 

a phylum of very small invertebrates, closely related to the Arthropoda, to which they were assigned until recently. The short body, which measures 0.1–1.0 mm in length, lacks distinct segmentation. It has four pairs of unjointed nodulelike legs, with two to nine long, setaceous tarsal digits. There are two ocelli. The mouth organs are a pair of sharp styles that serve to pierce the cell membranes of the algae and mosses that the Tardigrada feed on. The digestive tract is a straight tube extending the length of the body. Respiration is cutaneous. The organisms are dioecious. The young, which resemble adults, emerge from deposited eggs.

Representatives of the phylum, which comprises approximately 300 species, are ubiquitous, inhabiting seas, fresh waters, moss, and soil. Terrestrial species after drying are capable of surviving years in a state of anabiosis. Members of the phylum can tolerate several hours at temperatures as low as - 271°C and as highasl50°C.

References in periodicals archive ?
Minibiotus acadianus, a new species of Tardigrada from southern Louisiana, USA (Eutardigrada: Macrobiotidae).
The Tardigrada of southwest Virginia, with the addition of a description of a new marine species from Florida.
Ecological distribution and community analysis of Tardigrada from Choccolocco Creek, Alabama.
Partial mitochondrial gene arrangements support a close relationship between tardigrada and arthropoda.
IV Tardigrada (The Percy Sladen Trust Expedition to Lake Titicaca).
Despite the natural low presence of Tardigrada and Gastrotricha, the Jar method detected them in higher concentrations than in the other two.
Key words: Xenarthra, Tardigrada, Orophodontidae, Mylodontidae, Mylodontinae, Brievabradys laventensis, Miocene, La Venta, Colombia, Argentina.
Key Words: Tardigrade, Tardigrada, leaf litter, Georgia
SUMMARY: Sloth plows euterians mammals, belonging to the order Edentata, sub-order Xenarthra, infra-order Tardigrada, family Bradipodidae, which comprehend three specimen, Bradypus tridadctylus, Bradypus variegates and Bradypus torquatus.
A large-scale, multihabitat inventory of the Phylum Tardigrada in the Great Smoky Mountains National Park, USA: a preliminary report.
Orden Xenarthra Cope, 1899 Infraorden Tardigrada Latham & Davies, 1795 Familia [cruz] Mylodontidae Gill, 1872 Gen.
The ear region of edentates and the phylogeny of the Tardigrada (Mammalia: Xenarthra).