Crustacea, the Higher Taxa

J.K. Lowry


Tanaidacea (Peracarida, Malacostraca)

Description. Head. Rostrum present or absent; eyes sessile or stalked or absent; compound, visual elements present; ocular scale absent; naupliar eyes absent. Antennules (antenna 1) biramous, or uniramous; peduncle and flagellum distinct; endopod reduced, vestigial or absent; exopod well developed, whip-like or exopod reduced, vestigial or absent. Antennae (antenna 2) biramous, or uniramous; exopod multiarticulate. Mandible uniramous; palp present, or absent. Maxillipeds, 1 pair; uniramous. Thorax. Carapace present, univalved, enclosing head and anterior thoracic somites, dorsoventrally flattened, smooth. Thorax and abdomen differentiated. Peraeopods (legs) 7 pairs; biramous, or uniramous; non-phyllopodous; differentiated (some prehensile). Abdomen with 5 somites or with 4 somites. Epimera absent. Pleopods present or absent, 5 pairs or 3 pairs or 2 pairs or 1 pair; well developed, broad and flat, or reduced. Uropods well developed, 1 pair, positioned terminally or subterminally; rami present (biramous or uniramous), exopod with diaresis, partial or complete or exopod without diaresis (multiarticulated); endopod without statocyst. Telson fused to pleon (pleotelson).

Larval development. Epimorphic. Embryos carried in ventral thoracic brood pouch.

Habitat. Marine; occasionally brackish or freshwater.

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/.