| Petalophthalmidae | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Superorder: | Peracarida |
| Order: | Mysida |
| Family: | Petalophthalmidae Czerniavsky, 1882 [1] |
| Genera | |
See text | |
Petalophthalmidae is a family of marine crustaceans in the order Mysida, the opossum shrimps.
Petalophthalmidans are distinguished from other mysids by the fact that the first pereopod (walking leg) does not have an exopod (outer branch), the carpopropodus of the endopod (inner branch) of the 3rd to 8th pereopods are not fused and there is no statocyst on the endopod of the uropods (posterior appendage). Female petalophthalmidans have seven oostegites (flexible bristly flaps) forming the base of the marsupium or brood pouch under the thorax. Most species in this genus are bathypelagic and live on or near the seabed in the deep ocean. [2]
The following genera are recognised in the World Register of Marine Species: [1]
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.
Mysidae is the largest family of crustaceans in the order Mysida, with over 1000 species in around 170 genera.
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
Balanoglossus is a genus of ocean-dwelling acorn worms (Enteropneusta). It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. Balanoglossus is a deuterostome, and resembles the sea squirts (Ascidiacea) in that it possesses branchial openings, or "gill slits". It has a notochord in the upper part of the body and has no nerve chord. It does have a stomochord, however, which is a gut chord within the collar. Their heads may be as small as per 2.5 mm (1/10 in) or as large as 5 mm (1/5 in).
A salp or salpa is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient examples of jet propulsion in the animal kingdom. The salp strains the pumped water through its internal feeding filters, feeding on phytoplankton.
Misszhouia is a genus of small to average sized marine arthropods within the Naraoiidae family, that lived during the early Cambrian period. The only species presently known is Misszhouia longicaudata and the holotype was discovered in 1984.
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.
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:
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Mysidopsis is a genus of mysid shrimps in the family Mysidae. The sensitivity of these shrimps to water quality makes them suitable for bioassays. Mysidopsis bahia and Mysidopsis almyra, which are used frequently to test for pesticides and other toxic substances, are now classified as Americamysis bahia and Americamysis almyra.
Lauridromia is a genus of crabs in the family Dromiidae. It contains only two species. At one time a third species, Lauridromia indica, was included in the genus but that has now been transferred to the genus Dromidiopsis as Dromidiopsis indica.
Gastrosaccus spinifer is a shrimp-like crustacean in the order Mysida, the opossum shrimps, native to the eastern Atlantic Ocean and the coasts of Northern and Western Europe.
Calcinus morgani, commonly known as Morgan's hermit crab, is a species of hermit crab in the family Diogenidae found in the Indo-West Pacific region, the type locality being Indonesia.
Heteromysis is a genus of marine mysid crustaceans from the family Mysidae, associated with various shallow-water invertebrates. The name describes differentiation of its pereiopods as possible adaptation to commensal life-style. Heteromysis is one of the largest mysid genera, containing more than 100 species. The genus is distributed globally, but predominantly in tropical and subtropical waters.
Longipedia is a genus of marine copepods of the family Longipediidae, order Canuelloida.
Erratus is an extinct genus of marine arthropod from the Cambrian of China. Its type and only species is Erratus sperare. Erratus is likely one of the most basal known arthropods, and its discovery has helped scientists understand the early evolution of arthropod trunk appendages. Some of the stem-arthropods like radiodonts did not have legs, instead they had flap like appendages that helped them swim. Erratus on the other hand had not only flaps but also a set of primitive legs. It also supported the theory that the gills of aquatic arthropods probably evolved into the wings and lungs of terrestrial arthropods later in the Paleozoic.
Ergasilus curticrus is a freshwater parasitic copepod named in 2015. Described from the Orinoco river basin, it was found solely to be hosted by individuals of the Characiform fish species Bryconops giacopinii. Of those located in South America, it is one of only five species in its genus to be found outside of Brazil.