crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s. It consists of the following classes:
Class Mystacocarida: Minute crustaceans (0.5 to 1 mm in length) restricted to interstitial marine sediments. Locomotion depends completely on the presence of dorsal and ventral substrates.
Class
Ostracod
Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...
a (seed shrimp): Small planktonic, demersal and benthic crustaceans with a cosmopolitan aquatic distribution in both freshwater and marine environments, and a few in damp terrestrial habitats. Often called seed shrimps because their body is enclosed within a small and bivalved (with one exception) carapace, which makes them look like seed.
Class Ichthyostraca:
:Subclass Branchiura (fish lice): Ectoparasitic crustaceans on marine and freshwater fish, ranging in size from a few millimeters to 30 mm. A carapace is covering most of their body, which is dorsoventrally flattened. They are able to switch hosts several times even as adults.
:Subclass
Pentastomida
The Pentastomida are an enigmatic group of parasitic arthropods commonly known as tongue worms due to the resemblance of the species of the genus ''Linguatula'' to a vertebrate tongue; molecular studies point to them being highly derived crust ...
(tongue worms):
Vermiform
Vermes (" vermin/vermes") is an obsolete taxon used by Carl Linnaeus and Jean-Baptiste Lamarck for non-arthropod invertebrate animals.
Linnaeus
In Linnaeus's ''Systema Naturae'', the Vermes had the rank of class, occupying the 6th (and last) ...
endoparasites. The larvae develop in the tissues of mammals, reptiles, amphibians, fish, and a few species of coprophagous insects, which all are intermediate hosts. When eaten by other mammals, reptiles, amphibians and birds, which are the definitive hosts, the parasite develops to an adult (length 1–16 cm) found in the host's respiratory tracts. The genus Linguatula lives in the nasal cavity of mostly carnivorous mammals, but can also be found in humans, sheep and goats, and can sometimes reach the sinuses and middle ear.
Class Skaracarida: Long-bodied, marine, likely benthic detritivores. Only contains the genus ''
Skara
Skara is a locality and the seat of Skara Municipality, Västra Götaland County, Sweden with 18,580 inhabitants in 2013. Despite its small size, it is one of the oldest cities in Sweden, and has a long educational and ecclesiastical history. O ...