Ameribrachypoda Smith, 1991

Smith, Ian M., Cook, David R. & Gerecke, Reinhard, 2015, Revision of the status of some genus-level water mite taxa in the families Pionidae Thor, 1900, Aturidae Thor, 1900, and Nudomideopsidae Smith, 1990 (Acari: Hydrachnidiae), Zootaxa 3919 (1), pp. 111-156 : 130-131

Genus Ameribrachypoda Smith, 1991 stat. nov.

Phreatobrachypoda (in part): Cook, 1974a, pp. 365–366, figs. 1489–1498. Phreatobrachypoda (Ameribrachypoda) Smith, 1991 , pp. 466–467, 478–486, figs. 19–30. Phreatobrachypoda (in part): Smith & Cook, 1991, p. 577.

Phreatobrachypoda (in part): Smith et al., 2001, p. 613.

Phreatobrachypoda (in part): Smith et al., 2010, p. 554.

Diagnosis. Larva: Unknown.

Adults (modified from Smith 1991): Idiosoma broadly elliptical in shape in males, broadly elliptical or elongate elliptical in shape in females. Idiosomal sclerites with surfaces coarsely punctate or reticulate and with rough, scaly edges. Dorsal and ventral shields separate from one another. Dorsal shield bearing three pairs of glandularia and two pairs of well-defined longitudinal ridges, with posterior region of shield unmodified in males but constricted, depressed and bearing excretory pore, one pair of setae and one pair of lyrifissures in females. Dorsal furrow bearing two pairs of glandularia, two pairs of setae and three pairs of lyrifissures arranged on three pairs of platelets in males, and two pairs of glandularia, one pair of setae, and two pairs of lyrifissures arranged on two pairs of platelets in females. Fourth coxal plate bearing coxoglandularium II, and lacking or bearing small projection associated with opening for insertion of fourth leg. Ventral shield bearing a glandularium posteriorly. Genital field bearing ten to thirteen pairs of acetabula; genital field and excretory pore incorporated into posterodorsal urogenital plate that also bears a pair of setae, or into ventral shield, in males; excretory pore separated from genital field and located on dorsal shield in females; acetabular plates separate from or fused with ventral shield in females. Fourth leg of males with distal segments nearly straight and not expanded. Pedipalp with tibia relatively stout and less than twice as long as genu or relatively slender and more than twice as long as genu, bearing two sessile, slender setae ventrally.

Type species. Phreatobrachypoda robusta Cook.

Species included. Ameribrachypoda robusta (Cook) , A. acuta (Habeeb) , both from western North America.

Distribution. Western North America.

Discussion. Smith (1991) established Ameribrachypoda as a subgenus of Phreatobrachypoda Cook, 1963 . This treatment was followed by Smith & Cook (1991) and Smith et al. (2001, 2010). Here we propose to elevate Ameribrachypoda to full generic status based on the autapomorphic broadly elliptical shape of the body, coarse texture of the idiosomal sclerites and presence of two pairs of prominent ridges on the dorsal shield.