The Tanaidacea are small (generally up to 10 mm body length) malacostracan crustaceans of the Superorder Peracarida, superficially similar to, but distinct from, the Isopoda.
They are exclusively marine (although a few will move high up into estuaries), and probably at their most diverse in deeper waters. Almost all species have two sexes, although progynous hermaphroditism or sex-ratios heavily biased towards females are not uncommon. The young are brooded in a brood pouch carried ventrally by the females, and released as a non-dispersive miniature version of the adult - the manca. The adults are benthic in habit, commonly tubicolous (although one group lives in mollusc shells in the same manner as hermit crabs), and either burrowed into soft sediment, tube-building on algae or crevicial in holdfasts, fissured rock, barnacles, etc.
| Bunakenia aspalieus | Kalliapseudes tomiokaensis | Leptochelia savignyi |
| Pagurapseudopsis sp. | Pakistanapseudes sp. | Saltipedis achondroplasia |
