Crustacea, the Higher Taxa

J.K. Lowry

Brachyura (Decapoda, Eucarida, Malacostraca)

Common name. Crabs (Box Crabs, Fiddler Crabs, Fleet-footed Crabs, Ghost Crabs, Pebble Crabs, Semaphore Crabs, Sentinel Crabs, Soldier Crabs, Spider Crabs, Sponge Crabs, Swimming Crabs, etc.).

Description. Head. Rostrum present or absent; eyes stalked or absent; compound, visual elements present; ocular scale absent; naupliar eyes absent. Antennules (antenna 1) biramous; peduncle and flagellum distinct; endopod reduced, vestigial or absent; exopod reduced, vestigial or absent. Antennae (antenna 2) uniramous; exopod multiarticulate. Mandible uniramous; palp present, or absent. Maxillipeds, 3 pairs; biramous, or uniramous. Thorax. Carapace present, univalved, enclosing head and thorax, subcylindrical to cylindrical or dorsoventrally flattened, smooth or with spines. Sternum divided. Thorax and abdomen differentiated. Peraeopods (legs) 5 pairs, or 4 pairs; uniramous; non-phyllopodous; differentiated (some prehensile). Peraeopod 1 (leg 1) chelate. Peraeopod 2 (leg 2) simple. Peraeopod 3 (leg 3) simple, about the same size as other legs. Peraeopod 5 (leg 5) well developed, or reduced. Abdomen present, reduced in size and folded under thorax, abdomen with 6 somites. Epimera absent. Pleopods present, 5 pairs or 4 pairs; well developed, narrow and rounded; 1 and 2 forming reproductive organ in males. Uropods vestigial or absent (brachyurans, Dromiidae). Telson present (not fused to pleon).

Larval development. Metamorphic. Embryos attached to pleopods.

Habitat. Marine, freshwater and semiterrestrial.

Distribution. Worldwide.

Cite this publication as: Lowry, J.K. (1999 onwards). 'Crustacea, the Higher Taxa: Description, Identification, and Information Retrieval.' Version: 2 October 1999. http://crustacea.net/.