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 ?
Redescription of Echiniscus virginicus Riggin (Tardigrada) with notes on life history, range, and variation.
& GRIMALDI, D., 2000.--A new Eutardigrade (Tardigrada: Milnesiidae) in amber from the Upper Cretaceous (Turonian) of New Jersey: 103-110 (en) GRIMALDI, D.
A new water bear, Minibiotus julianae, from the Caribbean island of Dominica (Tardigrada: Eutardigrada: Parachela: Macrobiotidae).
Paleobiology of Pleistocene ground sloths (Xenarthra, Tardigrada): Biomechanics, morphogeometry and ecomorphology applied to the masticatory apparatus.
Echiniscus harharae, a new species of tardigrade from Cuba Island (Tardigrada: Fleterotardigrada, Echiniscidae, 'arctomys group').
Por ultimo, es importante tener en cuenta que el numero de especies ya identificadas esta alrededor de 960 o mas [58] dentro del phylum tardigrada; por lo tanto, esta tarea se convierte en algo bastante complejo.
61-100 1909-1958 1959-1978 Protozoa 59 2 Porifera 5 1 Coelenterata 34 (4) 1 Platyhelminthes 222 (13) 75 (4) Aschelminthes 12 0 Acanthocephala 3 6 Nematoda 0 3 (1) Annelida 13 3 Brachiopoda 67 0 Bryozoa 1 0 Echinodermata 33 0 Mollusca 81 (14) 0 Crustacea 233 (3) 59 Tardigrada 0 1 Trilobita 9 0 Myriopoda 25 0 Arachnoidea 169 (7) 39 Insecta 706 (19) 119 (3) Pisces 5 3 Amphibia 2 7 (1) Reptilia 14 4 Mammalia 52 (5) 4 TABLE 3.-New taxa, or new combinations, of plants cited in two cumulative index volumes.
As preguicas sao mamiferos euterianos, pertencentes a ordem Edentata, sub-ordem Xenarthra, infra-ordem Tardigrada, familia Bradipodidae.
(Tardigrada), Aelosoma variegatum Vejdovsky 1866 (Annelida), una especie de calanoideo (Artropoda) y Chironomus sp.
Although Louise had a research interest in Tardigrada, she always believed that she better served the University by spending her time improving her skills at introducing the science of biology to students.