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A phylum of free-living marine invertebrates less than 1 mm long. They are segmented and lack internal ciliation (see <b>illustration</b>). Kinorhyncha, formerly called Echinoderida, are sometimes included in the rejected superphylum Aschelminthes, since their fluid-filled body cavity is probably a pseudocoel, or false coelom. Kinorhynchs are benthonic, generally dwelling in mud or sand from intertidal to deep-sea habitats. Two orders are generally recognized, Cyclorhagida and Homalorhagida.
Industry:Science
A phylum of microscopic marine worms related to Rotifera and Micrognathozoa, mainly characterized by complex cuticular structures in the pharynx and a monociliated skin epithelium. Discovered in the 1920s on the German coast but not described until 1956, Gnathostomulida have since been reported from many sheltered sandy shores around the world. With fewer than 100 known species, this is one of the smallest animal phyla.
Industry:Science
A phylum of microscopic, mainly free-living aquatic animals, characterized primarily by an anterior ciliary apparatus, the corona. When the cilia of the corona are in motion the animals appear to have a pair of rapidly rotating wheels on their heads, thus the name “Rotifera,” Latin for “wheel bearers.” Rotifers were first observed by Anton Leeuwenhoek more than 300 years ago; because they are easy to find and of a convenient size for observation with a simple microscope, they have been avidly studied by amateur naturalists ever since.
Industry:Science
A phylum of minute metazoan animals (sometimes placed in the aschelminth group, in the Cycloneuralia, or in other combinations of phyla), mostly less than a millimeter in length. It presently numbers 600 described species worldwide. Some 380 species have been reported from the marine habitat, with new ones being described every year.
Industry:Science
A phylum of multicellular invertebrates. These marine organisms are entirely meiobenthic; that is, they never exceed a maximum dimension of 400 micrometers and live in sediments ranging from deep-sea red clay to coarse sand or shell hash. They have some of the smallest known cells in the animal kingdom. Although they have been found throughout the world, only 10 species representing three genera and two families have been described: the first described species (<i>Nannaloricus mysticus</i>) from shallow coastal waters near Roscof, France; eight species (including the first loriciferan seen, <i>Pliciloricus enigmaticus</i>) off North Carolina, and a single species from the western Pacific. Well over 50 species thought to represent several additional genera are known but remain undescribed.
Industry:Science
A phylum of primitive fungi characterized by production of predominantly aquatic fungi characterized by production of uniflagellate zoospores (asexually produced motile spores). Chytrids are basal in the fungal lineage and are thought to have diverged about 1 billion years ago from an ancestor shared with protistian groups such as the Choanoflagellates and Mesomycetozoa.
Industry:Science
A phylum of sedentary marine vermiform coelomates that are unsegmented, but possibly distantly related to the annelids; they are commonly called peanut worms. There are 17 genera and approximately 150 species living in a wide variety of oceanic habitats within the sediment or inside any protective shelter such as a discarded mollusk shell, foraminiferan test, or crevice in rock or coral.
Industry:Science
A phylum of sessile, aquatic, often colonial invertebrates having a looped gut with both mouth and anus situated inside a circlet of tentacles, a pseudocoelomate body cavity, and no hardened skeleton.
Industry:Science
A phylum of the invertebrates, commonly called the flatworms. They are bilaterally symmetrical, nonsegmented worms characterized by lack of coelom, anus, circulatory and respiratory systems, and exo- and endoskeletons. Many species are dorsoventrally flattened. They possess a protonephridial (osmoregulatory-excretory) system, a complicated hermaphroditic reproductive system, and a solid mesenchyme which fills the interior of the body. Some parasitic species, that is, some trematodes, have secondarily acquired a lymphatic system resembling a true circulatory system. Some species of trematodes, the schistosomes, have separate sexes.
Industry:Science
A phylum of worms formerly considered to be a class of the phylum Aschelminthes; commonly called the hairworms, and closely allied to the nematodes. The adults are free-living in aquatic habitats, while the juveniles are parasitic in arthropods. The nematomorphs are found all over the world. They are divided into two classes, the Nectonematoidea and Gordioidea, with a total of 225 species.
Industry:Science
