Belongs within: Thecostraca.Contains: Scalpellomorpha, Lepadiformes, Balanomorpha. The Thoracica are the barnacles, sessile crustaceans in which the legs have been modified into a filter-feeding fan while the body is armoured with calcareous plates. The Thoracica have been divided into the Pedunculata (goose barnacles, etc.) in which the body is supported by a fleshy peduncle, and Sessilia… Continue reading Thoracica


Belongs within: Euarthropoda.Contains: Rhizocephala, Thoracica. The Thecostraca are a crustacean clade containing barnacles (Thoracica) and their close relatives. Within the clade, Ascothoracida and Rhizocephala are parasitic lineages, while Acrothoracica are sessile filter-feeders that burrow into the surface of an animal host. Hansenocaris is known only from juvenile specimens; adults are unknown but are perhaps also… Continue reading Thecostraca


Belongs within: Thoracica.Contains: Tetraclita, Balanidae, Pyrgomatidae. The Balanomorpha are the clade of barnacles containing the familiar acorn barnacles. Members of the clade are characterised by a symmetrical wall formed of 1, 4, 6 or 8 plates, and with the operculum usually formed from paired terga and scuta. At least the first two pairs of cirri… Continue reading Balanomorpha