There are at least 30 species of crustaceans found in Montana. [1] The Montana Department of Fish, Wildlife and Parks has identified a number of crustacean species as Species of Concern. [Note 1]
There are at least 30 species of crustaceans found in Montana. [1] The Montana Department of Fish, Wildlife and Parks has identified a number of crustacean species as Species of Concern. [Note 1]
Crustaceans (Crustacea) form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at 0.1 mm (0.004 in), to the Japanese spider crab with a leg span of up to 12.5 ft (3.8 m) and a mass of 44 lb (20 kg). Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates by the possession of biramous (two-parted) limbs, and by the nauplius form of the larvae.
Most crustaceans are free-living aquatic animals, but some are terrestrial (e.g. woodlice), some are parasitic (e.g. fish lice, tongue worms) and some are sessile (e.g. barnacles). The group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis , which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimp and prawns. Krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology (alternatively, malacostracology, crustaceology or crustalogy), and a scientist who works in carcinology is a carcinologist.
Class: Malacostraca [3]
Class: Branchiopoda [4]
Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca, Notostraca, the Devonian Lepidocaris and possibly the Cambrian Rehbachiella. They are mostly small, freshwater animals that feed on plankton and detritus.
Malacostraca is the second largest of the six classes of pancrustaceans behind insects, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, spiny lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments, and divided into a head, thorax, and abdomen.
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, with similar forms having existed since the end of the Devonian, around 360 million years ago. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes.
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to 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, with the exception of Branchinecta gigas, or "giant fairy shrimp", which is itself a predator of other species of anostracans. 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.
Triops longicaudatus is a freshwater crustacean of the order Notostraca, resembling a miniature horseshoe crab. It is characterized by an elongated, segmented body, a flattened shield-like brownish carapace covering two thirds of the thorax, and two long filaments on the abdomen. The genus name Triops comes from Greek ὤψ or ṓps, meaning "eye" prefixed with Latin tri-, "three", in reference to its three eyes. Longicaudatus is a Latin neologism combining longus ("long") and caudatus ("tailed"), referring to its long tail structures. Triops longicaudatus is found in fresh water ponds and pools, often in places where few higher forms of life can exist.
The conservancy fairy shrimp is an endangered small crustacean in the family Branchinectidae. It ranges in size from about 1.25 centimetres (0.49 in) to 2.5 centimetres (0.98 in) long. This species is endemic to California in the United States.
The midvalley fairy shrimp, Branchinecta mesovallensis, is a small freshwater crustacean in the Branchinectidae family. The midvalley fairy shrimp was only recently formally described as a species in 2000 by Belk and Fugate. Midvalley fairy shrimp are endemic to shallow ephemeral pools near the middle of California's Central Valley. These vernal pool ecosystems are home to other unique organisms adapted to the ephemeral nature of the water cycle in the pools in California's mediterranean climate.
Branchinecta is a genus of fairy shrimp in family Branchinectidae. It includes around 50 species, found on all continents except Australia. Branchinecta gigas, the giant fairy shrimp, is the largest species in the order, with a length of up to 10 centimetres (4 in), and Branchinecta brushi lives at the highest altitude of any crustacean, at 5,930 metres (19,460 ft), a record it shares with the copepod Boeckella palustris. A new genus, Archaebranchinecta was established in 2011 for two species previously placed in Branchinecta.
Branchinecta longiantenna is a rare species of crustacean in the family Branchinectidae and the order Anostraca, the fairy shrimp. Its common name is longhorn fairy shrimp. It is endemic to California in the United States, where there are only four known populations. It is a federally listed endangered species of the United States.
Branchinecta sandiegonensis is a rare species of crustacean in the family Branchinectidae and the order Anostraca, the fairy shrimp. Commonly known as the San Diego fairy shrimp, it is named after the vernal pools found in San Diego County, California, where this species was originally discovered. It is also a federally listed endangered species of the United States.
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.
Streptocephalus woottoni, with the common name Riverside fairy shrimp, is a rare species of crustacean in the family Streptocephalidae. It is native to Southern California in the United States, and northern Baja California in northwest Mexico.
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.
Branchinecta gigas is a species of fairy shrimp that lives in western Canada and the United States. It is the largest species of fairy shrimp, growing up to 86 mm (3.4 in) long. It is known commonly as the giant fairy shrimp.
Archaebranchinecta barstowensis is a species of fairy shrimp (Anostraca) that inhabited California during the Middle Miocene. Its fecal material is abundant in the concretions from the Barstow Formation. A limited number of whole specimens have been found, and they represent the "best-preserved fossil anostracan known to date". The closest relative of A. barstowensis appears to be Archaebranchinecta pollicifera from the surroundings of Lake Titicaca, and the two have been separated from the genus Branchinecta as the new genus Archaebranchinecta.
Lepidurus apus, commonly known as a tadpole shrimp, is a notostracan in the family Triopsidae, one of a lineage of shrimp-like crustaceans that have had a similar form since the Triassic period and are considered living fossils. This species is cosmopolitan, inhabiting temporary freshwater ponds over much of the world, and the most widespread of the tadpole shrimps. Like other notostracans, L. apus has a broad carapace, long segmented abdomen, and large numbers of paddle-like legs. It reproduces by a mixture of sexual reproduction and self-fertilisation of females.
Eubranchipus is a genus of brine shrimp and fairy shrimp in the family Chirocephalidae. There are 21 described species in Eubranchipus.
