Mazepovacandona directa (Bronstein, 1947)

Karanovic, Ivana & Sitnikova, Tatiana Ya., 2017, Morphological and molecular diversity of Lake Baikal candonid ostracods, with description of a new genus, ZooKeys 684, pp. 19-56 : 22

Mazepovacandona directa (Bronstein, 1947) Figs 1, 2, 3, 14D, 15D

Candona directa sp. n. - Bronstein (1947): p.12, fig. 121

Candona directa Bronstein - Mazepova (1990): p. 73, fig. 20B

Material examined.

Two males and one female dissected and mounted on glass slides (shell of one male and one female on one SEM stub), 25 undissected specimens in 95% alcohol, 1 specimen used for the DNA extraction, all collected from 12-15 m depth by SCUBA diving off Listvyanka, 51°51'51.3"N, 104°50'37.8"E, 12 September 2015, collectors: Igor Khanaev and Ivan Nebesnykh.

Short redescription.

Almost no sexual dimorphism in shell shape in lateral view (Fig. 1 A–D). Both LV and RV subrectangular, dorsal margin straight and strongly inclined towards anterior end. Posterior end straight, anterior end rounded. RV with small recess antero-dorsally, ventral margin very slightly concave. Surface only centrally ornamented with shallow pits. Surface cuticular pores of two types: with simple lip and with semi operculum (Fig. 1E, F). Length around 1 mm.

A1 7-segmented with posterior setae transformed into claws (Fig. 3A). Male A2 with subdivided penultimate segment and t2- and t3-setae transformed into sexual bristles; z1- and z2-setae transformed into claws, as well asz3-seta; G1- and G3-claws reduced and short, G2-claw long (Fig. 2B). Female A2 (Fig. 3D) with all three z-seta untransformed; G2 claw short, and only slightly exceeding distal margin of terminal segment. Md-palp (Fig. 2C) with 3+2 setae on inner side, gamma seta not plumose. Mxl-palp (Fig. 2D) with rectangular terminal segment. Prehensile palps (Fig. 2G, H) with long bodies and short, curved fingers. L6 (Fig. 2G) with basal seta reaching far beyond distal margin of basal segment. L7 (Fig. 3A) clearly 5-segmented; basal segment with d1- and dp-seta; no e- or f-setae, g-seta long; terminal segment with setae h2- and h3- long and h1-seta shorter, but also considerably long. UR in both sexes (Figs 2H, 3C) very similar and robust, with long posterior seta and strong claws. Hemipenis always (?) in semi-erectile mode (Fig. 3B, 14D); a-lobe relatively small but its shape hard to accurately perceive due to its folded position; M-peace rounded distally, ejaculatory tube with pointed distal end. Female genital field (Fig. 3E) with enlarged, semi-triangular lobe. Zenker organ with 5+2 whorls of spines (Fig. 15D); anterior cap hemispherical, with strongly sclerified margin, lattice very elaborately developed and on side adjoined by longer spines. Eyes present, white.