Crayfish are freshwater crustaceans resembling small lobsters. In some parts of the United States, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, mudbugs, or yabbies. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some species are found in brooks and streams, where fresh water is running, while others thrive in swamps, ditches, and paddy fields. Most crayfish cannot tolerate polluted water, although some species, such as Procambarus clarkii, are hardier. Crayfish feed on animals and plants, either living or decomposing, and detritus.
The Rostratulidae, commonly known as the painted-snipes, are a family of wading birds that consists of two genera: Rostratula and Nycticryphes.
The Decapoda or decapods are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns, and shrimp. Most decapods are scavengers. The order is estimated to contain nearly 15,000 species in around 2,700 genera, with around 3,300 fossil species. Nearly half of these species are crabs, with the shrimp and Anomura including hermit crabs, porcelain crabs, squat lobsters making up the bulk of the remainder. The earliest fossil decapod is the Devonian Palaeopalaemon.
Remipedia is a class of blind crustaceans found in coastal aquifers which contain saline groundwater, with populations identified in almost every ocean basin so far explored, including in Australia, the Caribbean Sea, and the Atlantic Ocean. The first described remipede was the fossil Tesnusocaris goldichi. Since 1979, at least seventeen living species have been identified in subtropical regions around the world.
Clam shrimp are a taxon of bivalved branchiopod crustaceans that resemble the unrelated bivalved molluscs. They are extant, and known from the fossil record, from at least the Devonian period and perhaps before. They were originally classified in a single order Conchostraca, which later proved to be paraphyletic, being separated into three different orders: Cyclestherida, Laevicaudata, and Spinicaudata.
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes and Antarctic ice. They are usually 6–25 mm (0.24–0.98 in) long. Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia, and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families.
The Stenopodidea or boxer shrimps are a small group of decapod crustaceans. Often confused with Caridea shrimp or Dendrobranchiata prawns, they are neither, belonging to their own group.
Astacidea is an infraorder of decapod crustaceans including lobsters, crayfish, and their close relatives.
Leptostraca is an order of small, marine crustaceans. Its members, including the well-studied Nebalia, occur throughout the world's oceans and are usually considered to be filter-feeders. It is the only extant order in the subclass Phyllocarida. They are believed to represent the most primitive members of their class, the Malacostraca, and first appear in the fossil record during the Cambrian period.
Cancer is a genus of marine crabs in the family Cancridae. It includes eight extant species and three extinct species, including familiar crabs of the littoral zone, such as the European edible crab, the Jonah crab and the red rock crab. It is thought to have evolved from related genera in the Pacific Ocean in the Miocene.
Percopsidae is a family of fish in the order Percopsiformes, with one extant genus with two species, both endemic to North America, and two known fossil genera.
Palaemonidae is a family of shrimp in the order Decapoda. Many species are carnivores that eat small invertebrates, and can be found in any aquatic habitat except the deep sea. One significant genus is Macrobrachium, which contains commercially fished species. Others inhabit coral reefs, where they associate with certain invertebrates, such as sponges, cnidarians, mollusks, and echinoderms, as cleaner shrimps, parasites, or commensals. They generally feed on detritus, though some are carnivores and hunt tiny animals.
Lepidurus is a genus of small crustaceans in the order Notostraca. It is the larger of the two extant genera of the tadpole shrimps, the other being Triops. They are commonly found in vernal pools and survive dry periods with the help of long lasting resting eggs.
Branchinectidae is a family in the order Anostraca, containing two genera – Branchinecta and Archaebranchinecta. The majority of the species are in the genus Branchinecta, with only Archaebranchinecta pollicifera and the fossil Archaebranchinecta barstowensis in the second genus.
Polychelida is an infraorder of decapod crustaceans. Fossil representatives are known dating from as far back as the Upper Triassic. A total of 38 extant species, all in the family Polychelidae, and 55 fossil species have been described.
Goneplacoidea is a superfamily of crabs containing 11 extant families, and two families known only from fossils.
Cyzicidae is a family of crustaceans in the order Spinicaudata. They are distinguished from the family Leptestheriidae by the absence of a rostral spine. Some members of Cyzicidae are known to burrow through mud, leading to speculation that they may be filter feeders, but Martin reports that their mouthparts are indistinguishable from Leptestheriidae, which are believed to be grazers.
Leptestheriidae is a family of crustaceans in the order Spinicaudata. They are distinguished from the family Cyzicidae by the presence of a rostral spine. Members of Leptestheriidae are believed to graze on detritus.
Lynceidae is a family of clam shrimp in the order Laevicaudata. There are about 5 genera and more than 20 described species in Lynceidae.
