AXIIDEA HUXLEY, 1879

Wicksten, Mary K., 2012, Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371, Zootaxa 3371, pp. 1-307 : 130

INFRAORDER AXIIDEA HUXLEY, 1879

These lobster-like crustaceans formerly included in a single infraorder, the Thalassinidea , have been split into two infraorders based on genetic analyses ( Robles et al. 2009). De Grave et al. (2009) gave an extensive list of references on nomenclature of these decapods.

The rostrum varies from a tiny point to long and triangular or toothed. The eye may or be not pigmented. Pereopods 1, 2 are chelate, but the second are smaller than the first. The first pereopods may be dissimilar in size. The other pereopods end in paddles or simple dactyls. The abdomen is cylindrical, but the exoskeleton may vary from thin and weak to strongly calcified. A telson with flanking uropods is present. These decapods burrow into mud, sand or mixed surfaces.

Classification of the Axiidea has been an ongoing process. Manning & Felder (1991) wrote an extensive revision of the American callianassids, which contains diagnostic drawings and further information on the taxonomy. Poore & Collins (2009) wrote an extensive work on the genera and western Pacific species of the Axiidae . Sakai (2005) presented another system of classification of the Callianassidae and Ctenochelidae .The key presented here will differentiate between axiideans in the area of coverage but does not apply to tropical species. The latest classification of the Axiidea and Gebiidea does not include superfamilies ( De Grave et al. 2009).

The ghost shrimps (family Callianassidae ) are the best studied of the Axiidea . These burrowers range from the intertidal zone to the subtidal continental slope. They are deposit feeders. Their burrows provide shelter for other invertebrates, including shrimps ( Alpheidae ), crabs ( Pinnotheridae ), the clam Cryptomya californica (Conrad, 1837) and fishes (family Gobiidae ).

Little is known of the natural history of species belonging to other species of the Axiidea . In California and Oregon, species of the families Axiidae and Ctenochelidae are found on the continental shelf and slope.

Diagnoses in this section for the most part follow those of Hart (1982) and Williams (1986). MacGinitie & MacGinitie (1968), Haig &Abbott (1980), and Ricketts et al. (1985) gave extensive information on the natural history of near-shore species.