| Gammarus mucronatus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Superorder: | Peracarida |
| Order: | Amphipoda |
| Family: | Gammaridae |
| Genus: | Gammarus |
| Species: | G. mucronatus |
| Binomial name | |
| Gammarus mucronatus (Say, 1818) | |
Gammarus mucronatus is a species of scud in the family Gammaridae. It is found in the coasts of the North American Atlantic seaboard [1] and the Gulf of Mexico. [2] [3] [4]
Gammarus mucronatus is part of the Arthropod phylum: it has an external skeleton - or cuticle - with a body made up of articulated segments-bearers of appendages which are themselves articulated, and a growth by molting. More specifically, G. mucronatus is a Malacostraca, which is the monophyletic group of the superior crustaceans. Malacostraca are subdivided in three subclasses: Phyllocarida, Hoplocarida and Eumalacostraca. Like the vast majority of the Malacostraca, G. mucronatus belongs to the Eumalacostraca and more specifically to the Peracarida. This superorder is characterized by the presence of a marsupium (an abdominal sac sheltering the eggs) formed by the oostegites, the flat and flared parts of the proximal segments of the legs. G. mucronatus belongs to the Amphipods, an order of the Peracarida, defined by the two kinds of legs that they possess. G. mucronatus belongs to the Gammaridae family. More specifically, the species of Gammarus mucronatus was described for the first time in 1818. [2]
Pierre-André Latreille (1762-1833), an important French entomologist specialized in the taxonomy of arthropods, coined the term Amphipoda in 1816. It comes from the Greek: amphi = on either side, and pode = leg. It is an allusion to the apparent distribution of the legs in 2 groups one directed towards the front (used to cling to the substrate and grasp the food) and the other towards the rear (ambulatory or swimming legs). This term is coined in opposition to the Isopoda, another order of the Peracarida, which only present a single type of leg. [5] Pierre-André Latreille also coined the term Gammaridae, which describes the family of Gammarus mucronatus.
Gammarus mucronatus is relatively small: organisms’ size varies between 3.5 and 6.5 mm. [1] That size seems to remain stable between habitats. However, a reduction in size of ovigerous and mature females from the winter months to the summer has been observed. [6] G. mucronatus has no carapace and a laterally compressed body, which is a synapomorphy of the Amphipods. [7]
Gammarus mucronatus is eurytopic, which means that it is capable of tolerating a wide range of ecological conditions. For example, it can withstand a wide range of salinity levels from 4 to 35‰. [6] It is generally found in the endemic shallow waters and coasts of the North American Atlantic seaboard and the Gulf of Mexico. It is therefore found in very different habitat: algae, [1] grass beds, sponges, spartina marshes, soft bottoms with shells or cobbles, oysters bar and open beaches. [6] It is a benthic organism, which means that it lives at the bottom of the water. [8]
Sex are differentiated between females and males. Brood development lasts a mean of 31 days. [6] The females are multivoltine, which means they have several broods in one season. [1] That means that there is several cohorts of Gammarus mucronatus, which sometimes overlap. Winter and summer populations of G. mucronatus have different reproduction strategies, with the summer population having reduced egg size, brood size, development time, size at maturity, and maximum size. [6] The mean cohort interval is 112 days and its mean turnover rate is 4.3. [1] Most of the mature females are ovigerous. [6] Each female produces between 3 and 200 eggs. That production depends on the female's size: the bigger a female is, the more eggs she will produce. There is also a variation in the egg's size from 0.308 to 0.532 mm. The egg size varies seasonally, decreasing from winter to summer. The density of the G. mucronatus population peaks in late June. [1] [6]
Gammarus mucronatus has a diversified diet: it is detritivore but also eats microalgae and macroalgae, and possibly some other macrofauna. It lacks the enzymatic activity towards structural plant polysaccharides. However, G. mucronatus can break down the glycosidic linkages in smaller molecules. It can process starch and laminarin. [9]
In seagrass beds, G. mucronatus may have different ecological roles. It participates in the decomposition process and also engage in grazing of sea grass epiphytes. [6] Moreover, large decapods, crustaceans, juvenile and adult fishes prey on G. mucronatus, [6] like the stripped killfish, Fundulus majalis. [8] The activity of those predators depends on the presence or the absence of some organisms in the habitat of G. mucronatus. The presence of macroalgua reduces the predation of G. mucronatus by fish, which directly has a positive effect on their population’ size [8] and could create ternate stable states.
Malacostraca is the largest of the six classes of crustaceans, 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 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.
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from 1 to 340 millimetres and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as Talitrus saltator.
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.
Phronima is a genus of small, deep sea hyperiid amphipods of the family Phronimidae. It is found throughout the world's oceans, except in polar regions. Phronima species live in the pelagic zone of the deep ocean. Their bodies are semitransparent. Although commonly known as parasites, they are more technically correctly called parasitoids. Instead of constantly feeding on a live host, females attack salps, using their mouths and claws to eat the animal and hollow out its gelatinous shell. Phronima females then enter the barrel and lay their eggs inside, and then propels the barrel through the water as the larvae develop, providing them with fresh food and water.
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.
Themisto gaudichaudii is an amphipod crustacean of the suborder Hyperiidea.
Gammarus roeseli is a species of freshwater amphipod native to Europe.
Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains more than 200 described species, making it one of the most species-rich genera of crustaceans. Different species have different optimal conditions, particularly in terms of salinity, and different tolerances; Gammarus pulex, for instance, is a purely freshwater species, while Gammarus locusta is estuarine, only living where the salinity is greater than 25‰.
Gammarus desperatus, commonly known as Noel's Amphipod, is a species of small, amphipod crustacean in the family Gammaridae.
Gammarus hyalelloides is a species of amphipod crustacean in the family Gammaridae. It is endemic to four springs in Jeff Davis County and Reeves County, Texas, and is listed as a vulnerable species on the IUCN Red List.
Gammarus chevreuxi is a species of crustacean in the family Gammaridae. It was first described by Elsie Wilkins Sexton in 1913. The organism is very similar to Gammarus locusta, but there are certain constant characters which set it apart, for example, the antennae, the fourth side-plates and the third uropods. It is found in various places in England, such as the Severn Estuary, and in Portugal.
Dikerogammarus villosus, also known as the killer shrimp, is a species of amphipod crustacean native to the Ponto-Caspian region of eastern Europe, but which has become invasive across the western part of the continent. In the areas it has invaded, it lives in a wide range of habitats and will prey on many other animals. It is fast-growing, reaching sexual maturity in 4–8 weeks. As it has moved through Europe, it threatens other species and has already displaced both native amphipods and previous invaders.
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.
Parhyale hawaiensis is an amphipod crustacean species that is used in developmental and genetic analyses. It is categorized as an emerging model organism as the main biological techniques necessary for the study of an organism have been established.
Caprella mutica, commonly known as the Japanese skeleton shrimp, is a species of skeleton shrimp. They are relatively large caprellids, reaching a maximum length of 50 mm (2.0 in). They are sexually dimorphic, with the males usually being much larger than the females. They are characterized by their "hairy" first and second thoracic segments and the rows of spines on their bodies. Body color ranges from green to red to blue, depending on the environment. They are omnivorous highly adaptable opportunistic feeders. In turn, they provide a valuable food source for fish, crabs, and other larger predators. They are usually found in dense colonies attached to submerged man-made structures, floating seaweed, and other organisms.
Crustaceans form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustaceans. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
The clade Multicrustacea constitutes the largest superclass of crustaceans, containing approximately four-fifths of all described crustacean species, including crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods, mantis shrimp and others. The largest branch of multicrustacea is the class Malacostraca.