Pseudocandona renalis Mazepova, 1982

Figs. 22–26; 40E; 41E; 42E

Type locality. Lake Baikal, coastal zone of Peschanaya Bay (approximate coordinates: 52°15′37 N, 105°42′17 E).

Type material. Lectotype No. O2 (male) and paralectotype No. 1 (female):dwm No. O1-150866. Paralectotypes Nos. 2–7 (3 females, 3 males): dwm No. O2-150866. Paralectotypes Nos. 8–17 (5 females, 5 males): dwm No. O3- 150866. Paralectotypes Nos. 18–26 (four females, four males): swm No. x963. Paralectotype No. 22 (female): swm No. x963 (one valve) and wm O7-150866 (limbs). Paralectotype No. 27 (male): swm No. x963 (valves) and wm No. O4-150866 (limbs). Paralectotype No. 28 (female): dwm No. O3-150866 (valves) and wm No. O5-150866 (limbs). Paralectotype No. 29 (male): dwm No. O3-150866 (valves) and wm No. O6-150866 (limbs). Paralectotype No. 30 (female): swm No. x963 (valve with soft body).

All specimens were collected in Lake Baikal, southern basin, in the coastal zone of Peschanaya Bay, August 15, 1966, depth 10–11 m, sample No. 22 from the collection of G.F. Mazepova.

Description. Female. Carapace (Figs. 22A–22G; 23A–23F; 40E) laterally kidney-shaped-trapezoidal; L = 815–860 µm (average 840 µm, n = 5), greatest H = 475–495 µm (average 485 µm, n = 5) located on border of anterior 1/3 of L. Dorsal margin straight. Anterior margin of valves widely rounded, posterior one almost straight. LV overlaps RV throughout, except for anterior margin. Ventral margin concave on inner and outer sides. Inner lamella broad; marginal pore canals occupy 70–100% of inner lamella. Inner lamella of each valve with 35–45 marginal pore canals. Sensillae of outer lamella sparse. Microrelief of valve surface pitted, heterogenous. Pits well expressed in central part of valves; along carapace margin, microrelief strongly smoothed. Microrelief absent near dorsal margin, and well expressed on ventral side. Site of greatest width (both from ventral and dorsal sides) slightly behind center of L of carapace.

A1 (Fig. 25A) seven-segmented. First segment with one seta. Second segment with three setae, two of almost equal length, one shorter. Third segment with one seta. Fourth segment with two small setae. Fifth segment with two claws and one seta. Sixth segment with three claws of different lengths and two setae. Seventh segment with two claws of different lengths, one short seta and small stick-shaped aesthetasc (ya).

A2 (Fig. 25D–25F) five-segmented. Coxal segment with three setae, one of them inserted on this segment, two located between coxal and basal segments. One of them pappose, plumose along its entire length, except for proximal tip. Basal segment with one ventro-distal seta and rows of pseudochaetae.Exopod with three setae. Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posterodistal setae of almost equal length and row of pseudochaetae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y1), two t-setae of different lengths (t1 four times longer than t2), three z-setae (z1 four times shorter than z2 and six times shorter than z3), three G-claws (G2 2.5 times shorter than G1 and almost twice as short as G3) and small distal aesthetasc (y2). Last segment with two G-claws (GM and Gm) of different lengths, two setae, one of them basally fused with stick-shaped aesthetasc (y3).

Md. Coxa with one subapical seta and several setae between teeth of endite and on apical inner corner. Branchial plate with seven plumose setae and one smooth seta. Palp four-segmented. First segment with four setae: S1 (long, plumose), S2 (short, pappose), α (short and thin), and proximal seta. Second segment with six posterior setae (β-seta very small), two anterior setae, and row of pseudochaetae. Third segment with four posterodistal setae (γ-seta long and plumose), three anterior setae, and groups of pseudochaetae. Distal segment with two claws, three setae, and group of pseudochaetae.

Mxl. Protopod without setae. First endite with 14 setae, two at base of endite, 12 at apex. Second endite with nine apical setae. Third endite with eight setae and two claws. Palp two-segmented, first segment with three plumose setae and one smooth seta. Distal segment with two claws and one seta distally and three setae medially (two plumose and one smooth). Branchial plate with 24 setae and row of pseudochaetae.

L5 (Fig. 26A). Protopod with three setae (a, b, d). Endite with 14 setae, arranged in two groups of four and ten setae. Palp with three setae and several rows of pseudochaetae. Branchial plate in form of two setae of different lengths.

L6 (Fig. 26B) five-segmented. First through third segments with one distal seta (d1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h2) and two small setae (h1 and h3) of different lengths.

L7 (Fig. 26C) four-segmented. First segment with anterior d1-seta, posterior dp-seta, and rows of pseudochaetae; d2-seta absent. Second segment with rows of pseudochaetae. Third segment with one posterodistal g-seta and rows of pseudochaetae. Fourth segment with three serrate setae (h1–h3) of different lengths.

UR (Fig. 26D) symmetrical, with strongly curved main axis. Each ramus with one posterior seta distal to midramus, one short anterodistal seta, two distal claws of different lengths, and groups of pseudochaetae.

Male. Carapace (Figs. 22E–22H; 24A–24D; 40E) laterally kidney-shaped-trapezoidal, slightly longer and lower than in female; L = 825–870 µm (average 850 µm, n = 7), greatest H = 430–460 µm (average 445 µm, n = 7). Ventral margin of valves with small, barely noticeable projections. On RV projection rectangular, barely extending beyond valve margin (Fig. 24E, 24H), located almost on anterior 1/3 of L. On LV projection located at middle of valve length, barely noticeable in lateral view (Fig. 24B), but clearly visible in ventral view (Fig. 24F). Other morphological features of carapace structure (Fig. 24G), A1, A2 (protopod, exopod and first endopodal segment), Md, Mxl, L5 protopod, L6, L7 as in female.

A2 (Fig. 25G–25I). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y1), two t-setae of different lengths (t1 long, t2 very small), three z-setae (z1 and z2 transformed into long claws; z3 seta four times shorter than z1 and z2), three G-claws (G2 longest, G1 almost two times shorter than G2, G3 almost three times shorter than G2) and small distal aesthetasc (y2). Last segment with two G-claws (short GM and long Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y3).

Prehensile palps of L5 (Fig. 25B, 25C) asymmetrical. Right palp smoothly curved in central part, its thickness increases towards the place of insertion of two setae and smoothly decreases towards the distal end. Left palp crescent-shaped, curved more sharply, thick in proximal part and thin in distal part. Distal tip of both palps with thin seta.

Hemipenis (Fig. 41E) small, rectangular, 315 µm long and 155 µm wide; lobes oval, weakly protruding.

Zenker organ (Fig. 42E) 190 µm long, with 4+2 rings of spines 70 µm in diameter, central tube 30 µm in diameter, vesicle 50 µm in diameter.

UR (Fig. 26E) as in female, but main axis straighter.

Comparisons. P. renalis is most closely related to Pseudocandona ceratina Mazepova, 1982 . The carapaces of males of P. renalis have barely noticeable projections on the ventral side, while males of P. ceratina have long spines in the same places (Martens et al. 1992). The posterior margins of the female valves of both species are clearly different. Males of the compared species have different L5 prehensile palps and hemipenes.

Notes. When describing most endemic Baikalian ostracods, Prof. G.F. Mazepova did not distinguish holotypes, and the paratypes she designated (Mazepova 2001: p. 531) are not valid without a holotype designation. According to ICZN (1999), they should be considered as syntypes, which is what was done in this work.

The label in the tube containing the type specimens indicates 30 individuals (15 females, 15 males). In the tube itself, 31 individuals (16 females, 15 males) were found, which we examined.

Geographic distribution. Endemic to Lake Baikal, found in all three basins, in the Maloye More Strait, on the Ushkany Islands and near the Svyatoy Nos Peninsula at depths of 5–100 m (Mazepova 1990: p. 207). Lives on sandy and stony substrates with detritus and macrophytes.