Bythocypris malyutinae Brandão, 2008

Valves quite large; elongate and inequilateral (anterior margin more broadly rounded than posterior margin) in lateral view. External surface smooth, radial pore canals simple, with or without rim. LV with rounded outline, ventral margin straight, with upswung posterior angle, smoothly rounded dorsal margin. RV fairly sinuous in outline, especially the ventral margin; with truncate anterior margin, and slightly concave anterodorsal and posterodorsal margins. Females higher in relation to length than males. Adductor muscle scars bythocytherid, with 3 anterior (subdivided) scars and 1 posterior (subdivided) scar. Zone of concrescence fairly narrow with numerous short, straight marginal pore canals. Carapace subovate in dorsal view.

Antennula robust with not very long setae. Exopodite of antenna with 2 long and 1 short setae; segment VI of male with 1 long claw, 1 sexually dimorphic “6-segmented” medium-sized fused seta, and 2 or 3 simple medium-sized seta; segment VI of female with 1 long claw, 1 sexually dimorphic simple fused medium-sized claw, 2 or 3 medium-sized sim ple setae. Base of mandibula with 1 anterodorsal seta, masticatory process with 5 teeth plus several short setae; exopodite with 1 very long and 2 long feathered setae (one of the mandibles of one specimen with 1 very long and 3 long setae); segment IV of palp with 2 or 3 medium-sized setae and 2 mediumsized plumose claws. Maxillula with 5 to 9 strahlen (!) and 25 or 26 feathered setae; each endite with 1 to 4 plumose claws and around 5 setae; palp with 3 dorsal and 2 ventral setae, and 1 modified plumose claw. Fifth limb with 6 to 11 strahlen and 5 to 10 feathered setae, segment II might or might not be fused to segment III. Exopodite of sixth and seventh limbs with 2 medium-sized setae; one Ap of 1 specimen (SNB 0110) with 2 instead of 1 seta on segment 4. Furca with 2 rudimentary setae on dorsal margin; ventral margin with 4 or 5 short proximal setae, 1 medium-sized thin setae, 2 medium-sized robust setae, and 1 short distal seta. One short seta between furca rods. Genital lobe subtriangular, or suboval with tubularly extended distal margin. Male copulatory limb with coiled vas deferens; strongly sclerotized, sub-rectangular, arched, short proximal lobe; and subconical distal lobe armed distally with numerous chitinous spines.