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.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.

Mentioned in

References in periodicals archive

Tardigrades, also known as 'water bears' or 'moss piglets,' are considered to be the toughest animal phylum on the planet.

Organisms scattered onto surface of moon after spacecraft's crash

"Tardigrades can survive pressures that are comparable to those created when asteroids strike Earth, so a small crash like this is nothing to them," he told The Guardian.

Tiny water bears believed to be living on Moon after surviving spacecraft crash; The millimetre-long creatures can withstand extreme radiations and blazing heat in space

"Tardigrades are ideal to include because they are microscopic, multicellular, and one of the most durable forms of life on planet Earth," Spivack said.

'Indestructible' tardigrades may be alive on the Moon

When the results of the sequencing came back, the Tokyo researchers found that the tardigrade genome was composed of more like 1.2% foreign DNA, which is a far cry from a sixth of the thing's genes coming from lateral gene transfer.

Tardigrade DNA Inserted into Human Cells Gives Them X-Ray Resistance

Five hundred nineteen tardigrade specimens and 16 eggs were collected, representing nine genera and 18 species.

A contribution to the Tardigrade Fauna of Georgia, USA

Tardigrades are a class of microorganisms found abundantly in nature in regions spanning most climatic zones and altitudes across our seven continents.

The 7 biggest unsolved mysteries in science

Evolution attests that its proudest accomplishment is the incredibly resilient, microscopic and strangely adorable tardigrade.

Spread the holiday cheer

In our preceding studies (Lokko et al., 2013, 2014), 46 new zoopsammon taxa for the Estonian fauna were registered, including 25 rotifers, 17 testate amoebae, 1 cercozoan, 1 clitellate, 1 tardigrade, and 1 harpacticoid.

Taxonomic composition of zoopsammon in fresh and brackish waters of Estonia, a Baltic province ecoregion of Europe

& WOLF, M., 2009.--New molecular data for tardigrade phylogeny, with the erection of Paramacrobiotus gen.

Catalogo taxonomico de los ositos de agua (Tardigrada) de la cuenca baja de los rios Manzanares y Gaira, Santa Marta, Colombia

STRANGER THAN FICTION It looks like a Victorian illustration from Alice in Wonderland, but this image by Nicole Ottawa is in fact a tardigrade, or water bear, which is 1mm in length and was found on moss in Crater Lake, Tanzania

What on Earth? The everyday and exotic as you never see them