Macromckenziea giambonini Brandão, 2010

Description. Carapace medium-sized for the genus, non-equilateral, elongate in lateral outline, narrow zone of concrescence with straight radial pore canals, calcified inner lamella narrow. Greatest height at midlength in RV and anterior to mid-length in LV. Length approximately 2.3 times maximum height. RV larger than LV. Anterior margin of both valves narrowly rounded, dorsal margin gently arched, posterior margin rounded, ending in 90º posterior angle. Ventral margin straight in RV, and slightly concave in LV. Anterodorsal margin fairly straight in RV, slightly concave in LV. Antennula robust, thick, tapering, with 7 podomeres; Podomere II and III flexibly articulated. Antenna compact, thick-proportioned, tightly curled, with 6 podomeres; podomere IV short and thick. Mandibula with a broad masticatory jaw armed with one dorsal, conical tooth followed by four tricuspidate teeth and several setae. Maxillula with three slender endites, each armed distally with a dense fringe of subequal claws, ventral endite with 2 proximal setae on ventral margin, other 2 endites without proximal setae; vibratory plate with 1 strahlen and ~14 to ~17 feathered setae; palp slender, flexible; podomeres I and II fused, dorsal seta of podomere I absent). Exopodite of female fifth limb with 7 setae; podomeres IV and V with long and thin setae, mid-distal seta conspicuously longer than other 3 setae. Podomere IV and V of sixth limb short; podomere VI elongate, with 2 subequal, medium-sized, distal claws and one short distal seta. Seventh limb thin and small; podomere V with 2 ventrodistal, medium-sized setae, the most ventral one shortest; and with one very short reflexed-seta. Furca very small, each rod flexible and bearing 2 tiny proximal setae and one terminal, short seta.

Abbreviations: LV, left valve; RV, right valve.