| Diastylidae | |
|---|---|
 | |
| Diastylis laevis | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Superorder: | Peracarida |
| Order: | Cumacea |
| Family: | Diastylidae Bate, 1856 [1] |
| Genera | |
| |
Diastylidae is one of the eight most commonly recognised families of crustaceans of the order Cumacea. They are marine creatures especially common around the 30th parallel north. [2]
Diastylidae have a medium to large, free telson, that has not fused with the last pleon segment. The telson usually bears two terminal setae. [3]
Males have generally two pairs of pleopods, though in rare cases they may be rather small or even entirely absent. The flagellum of the second antenna reaches past the pereon. [3]
In females the second antenna is much smaller than the first antenna. In males the third maxilliped and the first four pereiopods almost always have exopods (outer branches). In females they may, in rare cases, be absent from all but the third maxillipeds, and the two first pereiopods. [3]
The interior branch of the uropods are generally made up of two or three segments, but in some rare case may have just one. Members of this family frequently show clear sexual dimorphism. [3]
There are around 285 species, [4] in 24 genera: [5]
Malacostraca is the second largest of the six classes of pancrustaceans just behind hexapods, 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, 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 decapod is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail:
The superorder Peracarida is a large group of malacostracan crustaceans, having members in marine, freshwater, and terrestrial habitats. They are chiefly defined by the presence of a brood pouch, or marsupium, formed from thin flattened plates (oostegites) borne on the basalmost segments of the legs. Peracarida is one of the largest crustacean taxa and includes about 12,000 species. Most members are less than 2 cm (0.8 in) in length, but the largest is probably the giant isopod which can reach 76 cm (30 in). The earliest known perecaridian was Oxyuropoda ligioides, a fossil of which has been found dating to the Late Devonian of Ireland.
Eumalacostraca is a subclass of crustaceans, containing almost all living malacostracans, or about 40,000 described species. The remaining subclasses are the Phyllocarida and possibly the Hoplocarida. Eumalacostracans have 19 segments. This arrangement is known as the "caridoid facies", a term coined by William Thomas Calman in 1909. The thoracic limbs are jointed and used for swimming or walking. The common ancestor is thought to have had a carapace, and most living species possess one, but it has been lost in some subgroups.
Cumacea is an order of small marine crustaceans of the superorder Peracarida, occasionally called hooded shrimp or comma shrimp. Their unique appearance and uniform body plan makes them easy to distinguish from other crustaceans. They live in soft-bottoms such as mud and sand, mostly in the marine environment. There are more than 1,500 species of cumaceans formally described. The species diversity of Cumacea increases with depth.
Diastylis is a genus of crustaceans which belong to the family Diastylidae. It includes the following species:
Bodotriidae is a family of crustaceans belonging to the order Cumacea. Bodotriids have a worldwide distribution in shallow and deep waters. There are over 380 described species in over 30 genera, being the most diverse cumacean family. Their external morphology differs from other cumaceans by a combination of traits that independently are not unique to the family: the telson is fused to the last abdominal segment, the dorsal part of the mandible has a boat shape (naviculoid), exopods exist on the third maxilliped and the first peraeopod, and there is a uropodal endopod with one or two articles.
Ceratocumatidae is a family of crustaceans of the order Cumacea. Ceratocumatidae have a small free telson. The endopods of the uropods are present on only one segment. Males have 5, 4 or 3 pairs of pleopods. All maxillipeds and some of the pereiopods bear exopods. The gill apparatus has no supporting gill plates.
Gynodiastylidae is one of the eight most commonly recognised families of crustaceans of the order Cumacea. They are especially prevalent in the southern hemisphere, with some types described from Japan, Thailand and the Persian Gulf. Most are found at less than 100 metres (330 ft) depth.
Lampropidae is a family of cold-water crustaceans belonging to the order Cumacea. Members of Lampropidae are relatively easily recognised because they all at have at least three terminal setae on the telson. The telson is medium to large and not fused with the last segment of the pleon. The endopods of the uropods are present on all three members. In the males the flagellum of the second antenna reaches beyond the carapace; moreover, they possess pleopods. In the females the second antenna is somewhat shorter than the first. There are exopods on the third maxilliped and strongly reduced or absent on the third pereopods.
Leuconidae is a family of marine hooded shrimp. The family was established by Georg Ossian Sars in his 1878 study of Mediterranean cumaceans.
Nannastacidae is a family of crustaceans belonging to the order Cumacea. They have no free telson. The endopods of the uropods are present on one segment. There are exopods on the maxillipeds and generally one on pereopods 1–4 in males and 1–2 in females. In the females the second antenna is much shorter than the first. It contains the following genera:
Bodotria is a genus of crustaceans which belong to the family Bodotriidae. It includes the following species:
Nannastacus is a genus of crustaceans in the order Cumacea. It contains the following species:
Phylogeny of Malacostraca is the evolutionary relationships of the largest of the six classes of crustaceans, containing about 40,000 living species, divided among 16 orders. Its members display a great diversity of body forms. Although the class Malacostraca is united by a number of well-defined and documented features, which were recognised a century ago by William Thomas Calman in 1904, the phylogenetic relationship of the orders which compose this class is unclear due to the vast diversity present in their morphology. Molecular studies have attempted to infer the phylogeny of this clade, resulting in phylogenies which have a limited amount of morphological support. To resolve a well-supported eumalacostracan phylogeny and obtain a robust tree, it will be necessary to look beyond the most commonly utilized sources of data.
Nototropis falcatus is a species of amphipod crustacean. It is whitish in colour, with brown patches, and grows to a total length of around 7 mm (0.3 in). It lives on soft sediment such as fine sand at depths of 10 to 50 metres, from northern Norway to the west coast of Ireland, including the North Sea, and as far south as the southern Bay of Biscay.
Stegocephalidae is a little-studied family of amphipods belonging to the suborder Gammaridea.
Campylaspis is a genus of crustaceans in the order Cumacea. Species of Campylaspis have a "bulky" carapace, which makes up more than 40% of the animal's length, as well as distinctive features of the mouthparts. There are currently 170 recognised described species:
Dimorphostylis echinata is a species of crustacean from the Diastylidae family. The scientific name of this species was first published in 1962 by Gamo.
Data related to Diastylidae at Wikispecies
Media related to Diastylidae at Wikimedia Commons