Crustaceans of Montana
Encyclopedia
There are at least 30 species of crustacean
s found in Montana
. The Montana Department of Fish, Wildlife and Parks
has identified a number of crustacean species as Species of Concern.
s, usually treated as a subphylum
, which includes such familiar animals as crab
s, lobster
s, crayfish
, shrimp
, krill
and barnacle
s. The 50,000 described species range in size from Stygotantulus stocki
at 0.1 mm (0.00393700787401575 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 arthropod
s, crustaceans have an exoskeleton
, which they moult
to grow. They are distinguished from other groups of arthropods, such as insect
s, 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 animal
s, but some are terrestrial
(e.g. woodlice
), some are parasitic
(e.g. fish lice
, tongue worms
) and some are sessile
(e.g. barnacle
s). The group has an extensive fossil record, reaching back to the Cambrian
, and includes living fossil
s 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
s and prawn
s. Krill
and copepod
s 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.
Crustacean
Crustaceans 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 , to the Japanese spider crab with a leg span...
s found in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
. The Montana Department of Fish, Wildlife and Parks
Montana Department of Fish, Wildlife and Parks
The Montana Department of Fish, Wildlife and Parks is a government agency in the executive branch state of Montana in the United States with responsibility for protecting sustainable fish, wildlife, and state-owned park resources in Montana for the purpose of providing recreational activities...
has identified a number of crustacean species as Species of Concern.
Crustaceans
Crustaceans (Crustacea) form a very large group of arthropodArthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s, usually treated as a subphylum
Subphylum
In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla...
, which includes such familiar animals as crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...
s, crayfish
Crayfish
Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
, shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
and barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s. The 50,000 described species range in size from Stygotantulus stocki
Stygotantulus
Stygotantulus stocki is a species of crustacean, living as an ectoparasite on harpacticoid copepods of the families Tisbidae and Canuellidae. It is the smallest arthropod in the world, at a length of less than . The specific epithet stocki commemorates Jan Hendrik Stock, a Dutch carcinologist....
at 0.1 mm (0.00393700787401575 in), to the Japanese spider crab
Japanese spider crab
The , Macrocheira kaempferi, is a species of marine crab that lives in the waters around Japan. It has the largest leg span of any arthropod, reaching up to and weighing up to . It is the subject of small-scale fishery.-Description:...
with a leg span of up to 12.5 ft (3.8 m) and a mass of 44 lb (20 kg). Like other arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s, crustaceans have an exoskeleton
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
, which they moult
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
to grow. They are distinguished from other groups of arthropods, such as insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, myriapods
Myriapoda
Myriapoda is a subphylum of arthropods containing millipedes, centipedes, and others. The group contains 13,000 species, all of which are terrestrial...
and chelicerates
Chelicerata
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda, and includes horseshoe crabs, scorpions, spiders and mites...
by the possession of biramous (two-parted) limbs, and by the nauplius form of the larvae
Crustacean larvae
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow...
.
Most crustaceans are free-living aquatic animal
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
s, but some are terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
(e.g. woodlice
Woodlouse
A woodlouse is a crustacean with a rigid, segmented, long exoskeleton and fourteen jointed limbs...
), some are parasitic
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
(e.g. fish lice
Branchiura
The family Argulidae contains the carp lice or fish lice – a group of parasitic crustaceans of uncertain position within the Maxillopoda. Although they are thought to be primitive forms, they have no fossil record...
, tongue worms
Pentastomida
Pentastomida are an enigmatic group of parasitic invertebrates commonly known as tongue worms due to the resemblance of the species of the genus Linguatula to a vertebrate tongue....
) and some are sessile
Sessility (zoology)
In zoology, sessility is a characteristic of animals which are not able to move about. They are usually permanently attached to a solid substrate of some kind, such as a part of a plant or dead tree trunk, a rock, or the hull of a ship in the case of barnacles. Corals lay down their own...
(e.g. barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s). The group has an extensive fossil record, reaching back to the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
, and includes living fossil
Living fossil
Living fossil is an informal term for any living species which appears similar to a species otherwise only known from fossils and which has no close living relatives, or a group of organisms which have long fossil records...
s such as Triops cancriformis
Triops cancriformis
Triops cancriformis, or tadpole shrimp , is a species of tadpole shrimp found in Europe, the Middle East and Japan....
, which has existed apparently unchanged since the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
s and prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
s. Krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
and copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s are not as widely fished, but may be the animals with the greatest biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...
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
Scientist
A scientist in a broad sense is one engaging in a systematic activity to acquire knowledge. In a more restricted sense, a scientist is an individual who uses the scientific method. The person may be an expert in one or more areas of science. This article focuses on the more restricted use of the word...
who works in carcinology is a carcinologist.
Malacostraca
Class: MalacostracaMalacostraca
Malacostraca is the largest of the six classes of crustaceans, containing over 25,000 extant species, divided among 16 orders. Its members display a greater diversity of body forms than any other class of animals, and include crabs, lobsters, shrimp, krill, woodlice, scuds , mantis shrimp and many...
- Astacid crayfishes Order: DecapodaDecapodaThe decapods or Decapoda 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. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, Family: AstacidaeAstacidaeThe family Astacidae comprises the freshwater crayfish native to Europe and western North America. It is made up of three genera. Pacifastacus is found on the Pacific coast of the United States and British Columbia and includes the signal crayfish and the Shasta crayfish...
- Pilose crayfish, Pacifastacus gambelii
- Signal crayfish, Pacifastacus leniusculusSignal crayfishThe signal crayfish, Pacifastacus leniusculus, is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the Scandinavian Astacus astacus fisheries, which were being damaged by crayfish plague, but the imports turned out to be a carrier of that disease...
- Cambarid crayfishes Order: DecapodaDecapodaThe decapods or Decapoda 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. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, Family: CambaridaeCambaridaeCambaridae is the largest of the three families of freshwater crayfish, with over 400 species. Most of the species in the family are native to North America east of the Great Divide, such as the invasive species Procambarus clarkii and Orconectes rusticus, with fewer species living in East Asia and...
- Calico crayfish, Orconectes immunisOrconectes immunisOrconectes immunis, the calico crayfish or papershell crayfish, is a species of North American freshwater crayfish which has also been introduced to Europe, where it lives along the Upper Rhine...
- Virile crayfish, Orconectes virilisOrconectes virilisOrconectes virilis is a species of crayfish known as the virile crayfish or the northern crayfish.-Ecology:Orconectes virilis can be found under stones in lakes, streams and wetlands, where they hide from predators, such as fish. They are identified by the brown of rust-red carapace and large...
- Calico crayfish, Orconectes immunis
- Gammarid amphipods Order: AmphipodaAmphipodaAmphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
, Family: CrangonyctidaeCrangonyctidaeCrangonyctidae is a family of cave-dwelling freshwater amphipod crustaceans. It contains the following genera:*Amurocrangonyx Sidorov & Holsinger, 2007 *Bactrurus Hay, 1902*Crangonyx Bate, 1859*Lyurella Derzhavin, 1939...
- Stygobromus montanensis
- Stygobromus obscurus
- Stygobromus puteanus
- Stygobromus tritus
- Glacier amphipod, Stygobromus glacialis
- Order: AmphipodaAmphipodaAmphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
, Family: GammaridaeGammaridaeGammaridae is a family of amphipods. In North America they are included among the folk taxonomic category of "scuds", and otherwise gammarids is usually used as a common name....
- Gammarus lacustrisGammarus lacustrisGammarus lacustris is an aquatic amphipod.-Description:G. lacustris is semi-transparent and lacks a webbed tail. It may be colorless, brown, reddish or bluish in color, depending on the local environment. It has seven abdominal segments, a fused cephalothorax, and two pairs of antennae. Unlike...
- Gammarus lacustris
- Order: AmphipodaAmphipodaAmphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
, Family: Hyalellidae- Hyalella aztecaHyalella aztecaHyalella azteca is a widepsread and abundant species of amphipod crustacean in North America. It reaches long, and is found in a range of fresh and brackish waters. It feeds on algae and diatoms and is a major food of waterfowl.-Description:...
- Hyalella azteca
- Order: IsopodaIsopodaIsopods are an order of peracarid crustaceans, including familiar animals such as woodlice and pill bugs. The name Isopoda derives from the Greek roots and...
, Family: AsellidaeAsellidaeAsellidae is a family of isopod crustaceans. It is one of the largest families of freshwater isopods, living in both epigean and hypogean habitats in North America and Europe...
- Salmasellus steganothrix
- Caecidotea communis
- Caecidotea racovitzai
Fairy shrimp
Class: BranchiopodaBranchiopoda
Branchiopoda is a class of crustaceans. It is the sister group to the remaining crustaceans, and comprises fairy shrimp, clam shrimp, Cladocera, Notostraca and the Devonian Lepidocaris...
- Branchinectid brine shrimp Order: Anostraca, Family: BranchinectidaeBranchinectidaeBranchinectidae 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....
- Circumpolar fairy shrimp, Branchinecta paludosa
- Colorado fairy shrimp, Branchinecta coloradensis
- Giant fairy shrimp, Branchinecta gigasBranchinecta gigasBranchinecta 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 long. It lives in turbid, hyposaline waters, and hunts smaller fairy shrimp by feel....
- Rock pool fairy shrimp, Branchinecta packardi
- Versatile fairy shrimp, Branchinecta lindahli
- Chirocephalid brine shrimp Order: Anostraca, Family: ChirocephalidaeChirocephalidaeChirocephalidae is a family of fairy shrimp, characterised by a reduced or vestigial maxilla, more than two setae on the fifth endite, divided pre-epipodites and widely separated seminal vesicles. It consists of the following eight genera, including the genera formerly placed in the families...
- Ethologist fairy shrimp, Eubranchipus serratus
- Ornate fairy shrimp, Eubranchipus ornatus
- Smoothlip fairy shrimp, Eubranchipus intricatus
- Clam shrimp Order: Spinicaudata, Family: Cyzicidae
- Bristletail clam shrimp, Caenestheriella setosa
- Clam Shrimp Order: Laevicaudata, Family: Lynceidae
- Hookleg clam shrimp, Lynceus mucronatus
- Fairy shrimp Order: NotostracaNotostracaThe order Notostraca comprises the single family Triopsidae, containing the tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, having not changed significantly in outward form since the Triassic. They have a broad, flat carapace, which conceals the...
, Family: Triopsidae- Bilobed tadpole shrimp, Lepidurus bilobatus
- Lemon tadpole shrimp, Lepidurus lemmoni
- Longtail tadpole shrimp, Triops longicaudatusTriops longicaudatusTriops longicaudatus is a freshwater crustacean of the order Notostraca, resembling a miniature horseshoe crab. It is characterized by an elongated, segmented body, flattened shield-like brownish carapace covering two thirds of the thorax and two long filaments on the abdomen...
- Round spine tadpole shrimp, Lepidurus couesii
- Streptocephalid brine shrimp Order: Anostraca, Family: Streptocephalidae
- Greater plains fairy shrimp, Streptocephalus texanus
- Spinytail fairy shrimp, Streptocephalus sealii
See also
- List of amphibians and reptiles of Montana
- List of birds of Montana
- List of clams and mussels of Montana
- Mammals of MontanaMammals of MontanaThere are at least 19 Large Mammal and 96 Small Mammal species known to occur in Montana.. Among Montana's mammals, three are listed as endangered or threatened species and the Montana Department of Fish, Wildlife and Parks lists a number of species as Species of Concern.Species are listed by...