Leptostraca

Leptostraca (from the Greek words for thin and shell) is an order of small, marine crustaceans. Its members, including the well-studied Nebalia, occur throughout the world's oceans and are usually considered to be filter-feeders. It is the only extant order in the subclass Phyllocarida. They are believed to represent the most primitive members of their class, the Malacostraca, and first appear in the fossil record during the Cambrian period.

Nebaliidae is the largest of the three families of leptostracan crustaceans, containing 33 of the 40 described species. Its members may be distinguished from members of the other two families by the tapering form of the caudal furcae (which is broader in Nebaliopsididae), and by the callynophores of the antennae in mature males, which are swollen in Paranebaliidae but not in Nebaliidae.

Nebalia is a large genus of small crustaceans containing more than half of the species in the order Leptostraca, and was first described by William Elford Leach in 1814. The genus contains over thirty species:

species of crustacean

Paranebaliidae is a family of crustaceans belonging to the order Leptostraca.

Nebaliopsididae is a family of leptostracan crustaceans. It contains only two species, the bathypelagic Nebaliopsis typica and the mesopelagic Pseudonebaliopsis atlantica.

species of crustacean

Nebaliella is a genus of leptostracan crustaceans within the family Nebaliidae. There are currently 7 species assigned to the genus.

Nebaliopsis typica is a species of leptostracan crustacean, the only species in the genus Nebaliopsis. It is exceptionally large for a leptostracan, at up to in length, compared to for the other species. It is also the only species not to brood its eggs, but instead lays them directly into the water; correspondingly, there is no sexual dimorphism in Nebaliopsis.