Crustacea, the Higher Taxa

J.K. Lowry


Gnathiidea (Isopoda, 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) uniramous; peduncle and flagellum distinct; exopod reduced, vestigial or absent; statocyst absent. Antennae (antenna 2) uniramous; exopod multiarticulate. Mouthparts modified to form suctorial cone, or not highly modified. Mandible uniramous, or absent. Maxillipeds, 2 pairs; second pair forming an operculum which covers the mouthparts (pylopod). Thorax. Carapace absent. Thorax and abdomen differentiated. Peraeopods (legs) 5 pairs; uniramous; non-phyllopodous; differentiated (some prehensile); pylopod present. Peraeopod 1 (leg 1) simple. Peraeopod 2 (leg 2) simple. Peraeopod 3 (leg 3) simple. Abdomen with 5 somites. Epimera present. Pleopods present; well developed, broad and flat. Uropods well developed, 1 pair, positioned ventrolaterally; rami present, exopod without diaresis; endopod without statocyst. Telson fused to pleon (pleotelson).

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

Habitat. Marine; adults benthic free-living, juveniles parasitic on fish.

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/.