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Taxon Pages
Macropyxis alanlordi Brandão, 2010
Nomenclature
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Family: MacrocyprididaeGenus: Macropyxis
SUMMARY
Carapace medium-sized (for the genus). In lateral view, valves elongate, slightly sinuous. RV with slightly convex ventral and dorsal margins; posterior margin relatively (for the genus) obtuse (around 60–70°); anterior margin narrowly rounded; maximum height at mid-length. LV with sinuous ventral margin; trisegmented dorsal margin, but with inconspicuous angles between segments, anterior segment slightly concave; anterior margin narrowly rounded; posterior margin pointed at around 45°; maximum height anterior to mid-length. Anterior zone of concrescence medium-sized, with ramified radial pore canals; posterior zone of concrescence thin, with straight radial pore canals. RV always larger than LV.
Antennula and antenna quite robust, with relatively thick and short podomeres and setae. Mandibula with one conical tooth and three or four tricuspidate teeth on the masticatory process; exopodite with one reduced seta and six to eight medium-sized setae. Vibratory plate of maxillula with two strahlen and more than 12 feathered setae; ventral endite with two basal setae; other two endites without basal seta. Podomere II of female fifth limb long; podomeres III to V short; podomere IV with one long, ventral seta; podomere V with two long, subequal setae and one medium-sized, dorsal seta. Right and left male fifth limb V fairly symmetrical; podomere II of male appendage V with two short, modified setae (= pegs) and one reduced seta; podomere III curved at approximately 90°, with one ventral, reduced seta and one distal, modified seta. Podomere VI of sixth limb with two long, thin claws and one short, ventral seta on distal margin. Seventh limb with thin and slender podomeres; podomere II with three long setae. Furca reduced, rods short and flexible, with four to five proximal, reduced setae; distal setae thin and slender, longer than rod itself. Male copulatory limb elongated, subrectangular, copulatory process located in the posterodorsal part of male copulatory limb, short, robust, and slightly curved. Zenker’s organ with weakly sclerotized and short central tube and very large terminal bulb; vas deferens very thin.