taxonID	type	description	language	source
0392A331E100FF9760D0F8A9FBD1FDBD.taxon	description	Figs. 1 – 7; 40 A; 41 D; 42 A	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E100FF9760D0F8A9FBD1FDBD.taxon	materials_examined	Type locality. Lake Baikal, Maloye More Strait, coastal zone opposite Arul Cape (approximate coordinates: 53 ° 28 ′ 27 N, 107 ° 32 ′ 54 E). Type material. Neotype No. O 9 (female): dwm No. O 1 - 120868. Additional material. Specimen No. 1 (male): dwm No. O 1 - 120868. Specimens Nos. 2 – 9 (8 females): dwm No. O 2 - 120868. Specimens Nos. 10 – 18 (9 males): dwm No. O 3 - 120868. Specimens Nos. 19 – 29 (4 females, 7 males): swm No. 39. Specimen No. 30 (female): swm No. 39 (valves) and wm No. O 4 - 120868 (limbs). Specimen No. 31 (female): swm No. 39 (valves) and wm No. O 5 - 120868 (limbs). Specimen No. 32 (male): wm No. O 6 - 120868 (limbs). Specimen No. 33 (male): wm No. O 7 - 120868 (limbs). Specimen No. 34 (male): wm No. O 8 - 120868 (limbs). Specimens Nos. 35 – 40 (6 juvenile stages): swm No. 40. All specimens were collected in Lake Baikal, in Maloye More Strait, coastal zone opposite Arul Cape, on August 12, 1968, at a depth of 5 m, in a habitat of stones with sponges and draparnaldia (most likely G. F. Mazepova meant representatives of the genus Draparnaldioides, endemic green macroalgae to Baikal), sample No. 170 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E100FF9760D0F8A9FBD1FDBD.taxon	description	Description. Female. Carapace (Figs. 1 A – 1 D; 2 A – 2 F; 40 A) laterally trapezoidal; L = 885 – 940 µm (average 905 µm, n = 9), greatest H = 520 – 600 µm (average 560 µm, n = 9) located on border of anterior 1 / 3 L. Dorsal margin of carapace straight, with small keel on LV, crescent-shaped in dorsal view (Fig. 2 D). Anterior margin of valves broadly rounded near ventral margin; posterior margin narrowly rounded. Central part of ventral margin of both valves almost equally concave on outer and inner sides. LV noticeably overlaps RV throughout. Inner lamella relatively broad; marginal pore canals occupy 30 – 50 % of width of inner lamella. Inner lamella of RV with more marginal pore canals (about 90) than inner lamella of LV (about 65). Difference in number of marginal pore canals occurs because area of inner lamella and marginal pore canals captures the posterior part of dorsal margin. Most often, canals reach margin of lamella and end with sensilla, rarely canals may not reach the margin of inner lamella and open before that. Sensillae of outer lamella relatively sparse and emerge from small outgrowths (Fig. 4 B). Outer lamella of each valve with 115 – 125 pore canals. Microrelief cellular (depressions and reticule of ribs as in Fig. 4 A, 4 B), almost homogeneous on most of valves. Size of cells gradually decreases from center of valves to their margin; cells become very small and shallow and almost disappear only on dorsal and ventral margins. Cellular microrelief slightly visible on inner side of valves (Fig. 2 E, 2 F). Site of greatest width (both on ventral and dorsal sides) slightly behind central part of carapace. A 1 (Fig. 5 A) seven-segmented. First segment with one plumose seta. Second segment with three setae (two of them almost same length, third is shorter) and row of pseudochaetae. Third segment with one seta. Fourth segment with two short setae. Fifth segment with two long setae. Sixth segment with five setae of different lengths. Seventh segment with three setae of different lengths and stick-shaped aesthetasc (ya). A 2 (Fig. 5 B, 5 C) five-segmented. Coxal segment with three setae, one inserted on this segment and two setae located between coxal and basal segments. One of them pappose. Basal segment with one ventro-distal seta and row of pseudochaetae. Exopod with three setae, one short and smooth, one short plumose and one long plumose (smooth in proximal third of length). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posteromedial setae of different lengths, and row of pseudochaetae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), three t-setae (t 1 – t 3) of approximately same length, three z-setae (z 1 – z 3), three G-claws (G 1 – G 3) of same length and small distal aesthetasc (y 2). Distal segment with two G-claws (GM and Gm; GM slightly longer than Gm) and two setae, one of which basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 6 F). Coxa with one subapical seta and several setae between teeth of endite and on apical inner corner. Branchial plate with seven plumed setae and one smooth seta. Palp four-segmented. First segment with four setae: S 1 (long, plumed), S 2 (short, pappose), α (thin and short) and proximal seta. Second segment with six posterior setae (β-seta very small), two anterior setae and row of pseudochaetae. Third segment with four posterior-distal setae (γ-seta large and plumed), three anterior setae and two rows of pseudochaetae. Distal segment with two claws, two setae (one short and other long) and group of pseudochaetae. Mxl (Fig. 6 A – 6 E). Protopod without setae. First endite with 14 setae, two of them at base of endite, 12 at apex. Second endite with eight setae at apex. Third endite with nine setae and two claws. Palp two-segmented; first segment with four setae and row of pseudochaetae, distal segment with two claws and one seta apically and three setae medially. Branchial plate with 24 setae and long row of pseudochaetae. L 5 (Fig. 7 C). Protopod with four setae (a, a’, b, d). Endite with 14 setae arranged in two groups of four and ten setae; two rows of pseudochaetae on endite. Palp with three setae and rows of small pseudochaetae. Branchial plate with two setae of different lengths. L 6 (Fig. 7 A) five-segmented. First to third segments with one distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 7 B) four-segmented. First segment with anterior d 1 - seta and posterior dp-seta; d 2 - seta absent. Second segment with rows of pseudochaetae. Third segment with one posterior-distal g-seta and rows of pseudochaetae. Fourth segment with three serrate setae (h 1 – h 3), all of different lengths. UR (Fig. 7 G) symmetrical, with slightly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta and two distal claws of different lengths. Male. Carapace (Figs. 1 E – 1 H; 3 A – 3 H; 40 A) laterally trapezoidal, slightly longer and higher than in female; L = 885 – 960 µm (average 920 µm, n = 10), greatest H = 570 – 620 µm (average 600 µm, n = 10) located in posterior 1 / 3 of L. Site of greatest H more pronounced than in female. Posterior margin of carapace slightly rounder than in female. Inner lamella relatively broad; marginal pore canals occupy 30 – 60 % of width of inner lamella. Other morphological features of carapace structure, A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 5 D, 5 E). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), three t-setae (long t 1 and small t 2 and t 3), three z-setae (z 1 and z 2 modified into long claws, and z 3 simple seta), three G-claws (G 1 and G 3 2.5 times shorter than G 2) and small distal aesthetasc (y 2). Last segment with two Gclaws (long Gm, and shorter GM basally fused with segment) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Figs. 4 D; 7 D, 7 E) slightly asymmetrical, thin and stick-shaped, main axis smoothly curved distal to insertion of one of setae. Right palp slightly thicker than left one. Medial setae on both palps different in size and structure: one long and inserted in center of palp, second short and located between insertion of first seta and distal tip of palp. Distal tip of both palps with thin seta. Hemipenis (Figs. 4 E; 41 D) small, rectangular, 295 µm long including lobes and 140 µm wide; lobes oval, strongly protruding, especially outer one. Zenker organ (Fig. 4 C; 42 A) 350 µm long, with 4 + 2 rings of spines 170 µm in diameter, diameter of central tube 30 µm, which corresponds to diameter of small proximal vesicle. UR (Fig. 7 F) as in female, but main axis straighter. Juvenile stages are almost identical to adults in carapace structure (Fig. 2 G – 2 I). Comparisons. Carapaces of P. alta individuals in lateral view are clearly distinguished from most Baikalian species of the genus. They are somewhat reminiscent of trapezoid shells of individuals of some species of the genus Baicalocandona Mazepova, 1976, but differ in the presence of a continuous cellular microrelief and five-segmented A 2 in both sexes. Notes. When describing the species, Z. S. Bronstein (1947) did not distinguish type specimens. In 2001, G. F. Mazepova designated syntypes (Mazepova 2001: p. 534), which cannot be syntypes, since they were collected only in 1968, which is significantly later than the publication of the original description. The designation of syntypes does not correspond to the International Code of Zoological Nomenclature (1999). For this reason, we designate a neotype based on the material of G. F. Mazepova. Geographic distribution. Endemic to Lake Baikal, found in all three basins and in the Maloye More Strait at depths of 1 – 25 m (Mazepova 1990: pp. 237, 238). Inhabits stony and sandy substrates.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E10FFF8F60D0FD61FB6EFD04.taxon	description	Figs. 8 – 14; 40 B; 41 B; 42 B	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E10FFF8F60D0FD61FB6EFD04.taxon	materials_examined	Type locality. Lake Baikal, between Peschanaya and Sennaya bays (approximate coordinates: 52 ° 16 ′ 19 N, 105 ° 43 ′ 15 E). Type material. Neotype No. O 10 (female): dwm No. O 1 - 200869. Additional material. Specimen No. 1 (male): dwm No. O 1 - 200869. Specimens Nos. 2 – 13 (12 females): dwm No. O 2 - 200869. Specimens Nos. 14 – 23 (10 males): dwm No. O 3 - 200869. Specimens Nos. 24 – 35 (4 females, 8 males): swm No. 38. Specimen No. 36 (female): swm No. 38 (valves) and wm No. O 4 - 200869 (limbs). Specimen No. 37 (female): swm No. 38 (valves) and wm No. O 5 - 200869 (limbs). Specimen No. 38 (male): swm No. 38 (valves) and wm No. O 6 - 200869 (limbs). Specimen No. 39 (male): swm No. 38 (valves) and wm No. O 7 - 200869 (limbs). All specimens were collected in Lake Baikal, southern basin, between Peschanaya and Sennaya bays, August 20, 1969, depth 11 m, stones with sponges and coarse sand, sample No. 209 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E10FFF8F60D0FD61FB6EFD04.taxon	description	Description. Female. Carapace (Figs. 8 A – 8 D; 9 A – 9 F; 40 B) laterally rectangular-trapezoidal; L = 1090 – 1145 µm (average 1110 µm, n = 10), greatest H = 675 – 730 µm (average 710 µm, n = 10). Site of greatest H poorly defined and located in posterior 1 / 4 of L. Valves asymmetrical: RV trapezoidal and LV rectangular-trapezoidal. Dorsal margin of carapace straight. Anterior margin of valves widely rounded near ventral margin; posterior margin rounded more narrowly. Ventral margin on RV equally concave on outer and inner sides, and on LV almost straight on outer side, and concave on inner side. LV slightly overlaps RV throughout. Inner lamella relatively broad; marginal pore canals occupy 80 – 100 % of inner lamella width. Inner lamella of each valve with 50 – 60 marginal pore canals. Most often, canal reaches margin of inner lamella and ends in sensilla; rarely, canals may not reach margin of inner lamella and open earlier. Sensillae of outer lamella relatively sparse and emerge from small outgrowths (Fig. 11 C). Outer lamella of each valve with about 65 canals. Microrelief pitted (Fig. 11 A – 11 C), almost homogenous on most valves, consisting of reticule of ribs and small rounded pits; pits gradually pass into reticule of ribs. Size of pits gradually decreases from carapace center to margins of valves, and on dorsal and ventral margin of valves, pits almost smooth out. Pitted microrelief visible on inner side of valves. Site of greatest width (both on ventral and dorsal sides) weakly expressed and located in central part of carapace. A 1 (Fig. 12 E) seven-segmented. First segment with one finely plumose seta. Second segment with three finely plumose setae, two of nearly equal length, one shorter. Third segment with one finely plumose seta. Fourth segment with two distal setae and one medial seta. Fifth segment with two claws of unequal length and one seta. Sixth segment with three claws of unequal length and two setae (one very small). Seventh segment with two claws of unequal length, one seta and a small stick-shaped aesthetasc (ya). A 2 (Fig. 12 A, 12 B) 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. Basal segment with one ventro-distal seta. Exopod with three setae, one of which short and smooth, one of medium length and smooth, and one long (large plumose in medial part). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posterodistal setae of almost equal length, and rows of pseudochaetae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae (t 1, t 2) of nearly equal length, three z-setae (z 1 half as long as z 2 and z 3), three G-claws (G 2 3 times shorter than G 1 and G 3), and small distal aesthetasc (y 2); segment with rows of pseudochaetae. Terminal segment with two G-claws (GM and Gm; GM longer than Gm), two setae, one of which basally fused with stick-shaped aesthetasc (y 3), and several rows of pseudochaetae. Md (Fig. 13 A). 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: S 1 (long, plumose), S 2 (short, pappose), α (short and thin), and proximal one. Second segment with six posterior setae (β-seta very small) and two anterior setae. Third segment with four posterodistal setae (γ-seta long and plumose) and three anterior setae. Distal segment with two claws, three setae, and group of pseudochaetae. Mxl (Fig. 13 B – 13 F). Protopod without setae. First endite with 15 setae, two of which inserted at base of endite, 13 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 in apical part and three setae in medial part. Branchial plate with 23 setae. L 5. Protopod with three setae (a, b, d). Endite with 14 setae, arranged in two groups of four and ten setae, and several rows of long pseudochaetae. Palp with three setae and rows of short pseudochaetae. Branchial plate in form of two setae of different lengths. L 6 (Fig. 14 C) five-segmented. First to third segments with one distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 four-segmented. First segment with anterior d 1 - seta, posterior dp-seta, and rows of pseudochaetae; d 2 - 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 (h 1 – h 3) of different lengths. UR (Fig. 14 E) symmetrical, with slightly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta, and two distal claws of nearly equal length. Male. Carapace (Figs. 8 E – 8 H; 10 A – 10 H; 40 B) laterally rectangular-trapezoidal, slightly shorter and lower than in female; L = 960 – 1065 µm (average 1020 µm, n = 10), greatest H = 625 – 650 µm (average 630 µm, n = 10). Site of greatest H slightly more pronounced and located in posterior 1 / 4 of L. Inner lamella relatively broad; marginal pore canals occupy 60 – 80 % of width of inner lamella. Inner lamella of each valve of same individual with 45 – 60 marginal pore canals. Other morphological features of carapace structure, A 1, A 2 (protopod, exopod and first endopodal segment, except for distal setae, which are of different lengths in male), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 12 C, 12 D). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae (t 1, t 2, shorter than in female), three z-setae (z 1 and z 2 modified into long claws, z 3 - seta as long as z 1 and z 2), three G-claws (G 2 longest, G 1 slightly shorter, G 2 2.5 the length of G 3), small distal aesthetasc (y 2) and rows of pseudochaetae. Terminal segment with two G-claws (short GM and long Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 14 A, 14 B) asymmetrical, stick-shaped, right one slightly stronger than left. Right palp smoothly curved in central part, and its thickness increases towards place of insertion of two medial setae (both in center of segment) and smoothly decreases distally. Left palp curved more sharply, its thickness smoothly decreases towards distal end. Medial setae of left palp inserted in different places: one in center of palp, second more proximally. Distal tip of both palps with thin seta. Hemipenis (Figs. 11 D; 41 B) large, rectangular, 390 µm long and 165 µm wide; lobes oval, weakly protruding. Zenker organ (Fig. 42 B) 255 µm long, with 4 + 2 rings of spines 95 µm in diameter; central tube 40 µm in diameter; proximal vesicle large, 85 µm in diameter. UR (Fig. 14 D) as in female, but rami slightly thinner. Comparisons. Due to the almost rectangular carapace, individuals of P. werestschagini are clearly distinguished from individuals of other Baikalian species of the genus, but in lateral view they remotely resemble individuals of Pseudocandona pseudosetosa Mazepova, 1990. Notes. As in the case of the previous species, type material was not isolated (Bronstein 1930), and syntypes (Mazepova 2001: pp. 532, 533) are incorrectly designated. The reasons are given in the Notes to the previous species. Geographic distribution. Endemic to Lake Baikal, found in all three basins and in the Maloye More Strait at depths from 3 to 100 m (Mazepova 1990: pp. 224, 225). Lives on sand, stones and silty substrate.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E117FF8060D0FD34FF60FF78.taxon	description	Figs. 15 – 21; 40 C; 41 C; 42 C; 43 A, 43 B	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E117FF8060D0FD34FF60FF78.taxon	materials_examined	Type locality. Lake Baikal, coastal zone of Senogda Bay (approximate coordinates: 55 ° 34 ′ 15 N, 109 ° 12 ′ 48 E). Type material. Holotype No. O 10 (male) and allotype No. O 10.1 (female): dwm No. O 10 - 260972. Paratypes Nos. 1 – 24 (24 females): dwm No. O 11 - 260972. Paratypes Nos. 25 – 62 (38 males): dwm No. O 12 - 260972. Paratypes Nos. 63 – 71 (4 females, 5 males): swm No. 42. Paratype No. 72 (female): swm No. 42 (valves) and wm No. O 13 - 260972 (limbs). Paratype No. 73 (female): swm No. 42 (valves) and wm No. O 14 - 260972 (limbs). Paratype No. 74 (female): swm No. 42 (valves) and wm No. O 15 - 260972 (limbs). Paratype No. 75 (male): swm No. 42 (valves) and wm No. O 16 - 260972 (limbs). Paratype No. 76 (male): swm No. 42 (valves) and wm No. O 17 - 260972 (limbs). Paratype No. 77 (male): swm No. 42 (valves) and wm No. O 18 - 260972 (limbs). Paratype No. 78 (male): swm No. 42 (valves) and wm No. O 19 - 260972 (limbs). Paratypes Nos. 79, 80 (male and female in copula): swm No. 42. All specimens were collected in Lake Baikal, northern basin, in the coastal zone of Senogda Bay, September 26, 1972, depth 10 m, slightly silted sand, sample No. 434 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E117FF8060D0FD34FF60FF78.taxon	etymology	Etymology. The species is named in honor of Mark J. Grygier (National Museum of Marine Biology & Aquarium, Taiwan), specialist in taxonomy, nomenclature, systematics, biology of crustaceans (Facetotecta, Ascothoracida, Monstrilloida) and previously a member of the Commission of the International Code of Zoological Nomenclature.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E117FF8060D0FD34FF60FF78.taxon	description	Description. Female. Carapace (Figs. 15 A – 15 D; 16 A – 16 H; 40 C) laterally rectangular-trapezoidal; L = 1090 – 1145 µm (average 1125 µm, n = 10), greatest H = 755 – 805 µm (average 780 µm, n = 10). Site of greatest H poorly expressed and located in posterior 1 / 4 of L. Valves asymmetrical: RV trapezoidal and LV rectangular-trapezoidal. Dorsal margin of carapace straight. Anterior margin of valves widely rounded near ventral margin; posterior and ventral margins form acute angle (about 75 °). Ventral margin on RV equally concave on outer and inner sides; on LV it is almost straight on outer side, and concave on inner side. LV slightly overlaps RV throughout. Inner lamella relatively broad; marginal pore canals occupy 70 – 100 % of width of inner lamella. Inner lamella of each valve with 55 – 60 marginal pore canals. Most often, canal reaches the margin of inner lamella and ends in sensilla; rarely, canals may not reach the margin of inner lamella and open earlier. Sensillae of outer lamella relatively sparse and emerge from small outgrowths (Fig. 18 C, 18 E). Microrelief pitted, almost homogenous on most of valves (Fig. 18 A). Pitted microrelief becomes more complex at posterior part of carapace: ribs appear in each pit, dividing the pit into smaller pits (in females, this microrelief less pronounced than in males in Fig. 18 B). Microrelief smoothed out at dorsal margin, valves almost smooth. Pitted microrelief visible on inner side of valves. Site of greatest width (both on ventral and dorsal sides) almost not expressed and located in central part of carapace. Anterior end of carapace in dorsal and ventral views is less sharp compared to previous species. A 1 (Fig. 19 A) seven-segmented. First segment with one finely plumed seta. Second segment with three setae, two of them almost equal length, one shorter and finely plumed. Third segment with one seta. Fourth segment with two distal setae and one medial seta. Very small area with residual division of segments in center of fourth segment near medial seta. Fifth segment with three setae of different lengths. Sixth segment with two claws of different lengths and three setae (one of them very small). Seventh segment with two claws of different lengths, one seta and small stick-shaped aesthetasc (ya). A 2 (Fig. 19 B, 19 C) five-segmented. Coxal segment with three setae, one of them inserted to this segment, two located between coxal and basal segments. One of them pappose. Basal segment with one ventro-distal seta. Exopod with three setae of different lengths, of which one short and smooth, one of medium length and finely plumed and one long and coarsely plumed (smooth in proximal length third). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posterodistal setae of equal length, and row of pseudochaetae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae (t 1, t 2) of equal length, three z-setae (z 1 four times shorter than z 2 and three times shorter than z 3), three G-claws (G 2 three times shorter than G 1 and G 3), small distal aesthetasc (y 2) and rows of pseudochaetae. Last segment with two Gclaws (GM and Gm; GM longer than Gm), two setae, one of them basally fused with stick-shaped aesthetasc (y 3) and row of pseudochaetae. Md (Fig. 20 A). 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: S 1 (long, plumose), S 2 (short, pappose), α (small and short) and proximal seta. Second segment with six posterior setae (β-seta very small) and two anterior setae. Third segment with four posterodistal setae (γ-seta long and plumose), three anterior setae and group of pseudochaetae. Distal segment with two claws, three setae and group of pseudochaetae. Mxl (Fig. 20 B – 20 F). 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 23 setae and row of pseudochaetae. L 5 (Fig. 21 A). Protopod with three setae (a, b, d). Endite with 14 setae, arranged in two groups of four and ten setae and two rows of pseudochaetae. Palp with three setae and numerous rows of small pseudochaetae. Branchial plate in form of two setae of different lengths. L 6 (Fig. 21 D) five-segmented. First through third segments with one distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 21 E) four-segmented. First segment with anterior d 1 - seta, posterior dp-seta, and rows of pseudochaetae; d 2 - 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 (h 1 – h 3) of different lengths. UR (Fig. 21 F) symmetrical, with slightly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta, and two distal claws of nearly equal length. Male. Carapace (Figs. 15 E – 15 H; 17 A – 17 H; 40 C) laterally rounded-trapezoidal, slightly longer and lower than in female; L = 1120 – 1195 µm (avearage 1150 µm, n = 10), greatest H = 730 – 780 µm (average 760 µm, n = 10). Posterior margin of carapace widely rounded, compared to that of female. Inner lamella narrower than in female; marginal pore canals occupy 40 – 100 % of width of inner lamella. Microrelief in form of large pits divided into smaller pits (Fig. 18 B) more pronounced than in female. Other morphological features of carapace structure, A 1, A 2 (protopod, exopod and first endopodal segments with except for distal setae, which of different lengths in male; Fig. 19 D), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 19 D, 19 E). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), one t-seta (t 1), three z-setae (z 1 and z 2 modified into long claws, z 3 - seta two times shorter than z 1 and z 2), three G-claws (G 2 longest; G 1 1.5 times shorter than G 2; G 3 2.5 times shorter than G 2), small distal aesthetasc (y 2), and rows of pseudochaetae. Last segment with two G-claws (short GM and long Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 21 B, 21 C) asymmetrical, main axis smoothly curved distally to insertion of two setae. Right palp slightly thicker than left. Medial setae of right palp attached next to each other. Medial setae of left palp attached in different places: one in center of palp, and other distally. Distal tip of both palps with very small seta. Hemipenis (Figs. 18 F; 41 C) large, oval-rectangular, 510 µm long and 235 µm wide (including lobes); lobes irregularly ovoid, strongly protruding. Zenker organ (Fig. 42 C) 305 µm long, with 4 + 2 rings of spines 150 µm in diameter, central tube 45 µm in diameter, small vesicle 50 µm in diameter. UR (Fig. 21 G) as in female, but rami slightly thinner. Comparisons. Female valves of the new species are generally similar to those of P. werestschagini females (Fig. 10 E, 10 F), but differ in an acute posterior end (Fig. 16 E, 16 F). Valve outlines of the males studied are significantly distinct (Figs. 10 A, 10 B; 17 A, 17 B). In dorsal and ventral views, the anterior and posterior ends of the carapaces of P. werestschagini males and females are thinner and more pointed (Figs. 9 C, 9 D; 10 C, 10 D, 10 G, 10 H) compared to the new species (Figs. 16 C, 16 D, 16 G, 16 H; 17 C, 17 D, 17 G, 17 H). In general, the shells of male and female specimens of the new species are noticeably wider. The microrelief of P. werestschagini specimens is pitted, almost homogeneous; individuals of P. grygieri sp. nov. have pits divided into smaller pits in the posterior part of the valves (Fig. 18 B). Comparisons of the limbs of the species show an array of differences (prehensile palps of the male L 5, size of the medial setae on the fourth A 1 segment and others). The male hemipenes also differ (Figs. 11 D; 18 F; 41 B, 41 C). The Zenker organs of P. werestschagini males have a much larger vesicle than that of the new species (Fig. 42 B, 42 C). Notes. Females and males in copula were found (Figs. 18 D; 43 A, 43 B). Geographic distribution. Endemic to Lake Baikal, found in Senogda Bay (depth 10 m). Lives on slightly silted sand.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E11EFFB960D0FF75FC90FA40.taxon	description	Figs. 22 – 26; 40 E; 41 E; 42 E	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E11EFFB960D0FF75FC90FA40.taxon	materials_examined	Type locality. Lake Baikal, coastal zone of Peschanaya Bay (approximate coordinates: 52 ° 15 ′ 37 N, 105 ° 42 ′ 17 E). Type material. Lectotype No. O 2 (male) and paralectotype No. 1 (female): dwm No. O 1 - 150866. Paralectotypes Nos. 2 – 7 (3 females, 3 males): dwm No. O 2 - 150866. Paralectotypes Nos. 8 – 17 (5 females, 5 males): dwm No. O 3 - 150866. Paralectotypes Nos. 18 – 26 (four females, four males): swm No. x 963. Paralectotype No. 22 (female): swm No. x 963 (one valve) and wm O 7 - 150866 (limbs). Paralectotype No. 27 (male): swm No. x 963 (valves) and wm No. O 4 - 150866 (limbs). Paralectotype No. 28 (female): dwm No. O 3 - 150866 (valves) and wm No. O 5 - 150866 (limbs). Paralectotype No. 29 (male): dwm No. O 3 - 150866 (valves) and wm No. O 6 - 150866 (limbs). Paralectotype No. 30 (female): swm No. x 963 (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.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E11EFFB960D0FF75FC90FA40.taxon	description	Description. Female. Carapace (Figs. 22 A – 22 G; 23 A – 23 F; 40 E) 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. A 1 (Fig. 25 A) 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). A 2 (Fig. 25 D – 25 F) 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 (y 1), two t-setae of different lengths (t 1 four times longer than t 2), three z-setae (z 1 four times shorter than z 2 and six times shorter than z 3), three G-claws (G 2 2.5 times shorter than G 1 and almost twice as short as G 3) and small distal aesthetasc (y 2). Last segment with two G-claws (GM and Gm) of different lengths, two setae, one of them basally fused with stick-shaped aesthetasc (y 3). 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: S 1 (long, plumose), S 2 (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. L 5 (Fig. 26 A). 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. L 6 (Fig. 26 B) five-segmented. First through third segments with one distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 26 C) four-segmented. First segment with anterior d 1 - seta, posterior dp-seta, and rows of pseudochaetae; d 2 - 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 (h 1 – h 3) of different lengths. UR (Fig. 26 D) 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. 22 E – 22 H; 24 A – 24 D; 40 E) 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. 24 E, 24 H), located almost on anterior 1 / 3 of L. On LV projection located at middle of valve length, barely noticeable in lateral view (Fig. 24 B), but clearly visible in ventral view (Fig. 24 F). Other morphological features of carapace structure (Fig. 24 G), A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 25 G – 25 I). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae of different lengths (t 1 long, t 2 very small), three z-setae (z 1 and z 2 transformed into long claws; z 3 seta four times shorter than z 1 and z 2), three G-claws (G 2 longest, G 1 almost two times shorter than G 2, G 3 almost three times shorter than G 2) and small distal aesthetasc (y 2). Last segment with two G-claws (short GM and long Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 25 B, 25 C) 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. 41 E) small, rectangular, 315 µm long and 155 µm wide; lobes oval, weakly protruding. Zenker organ (Fig. 42 E) 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. 26 E) 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 L 5 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.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E121FFB260D0F9E5FA39FA1C.taxon	description	Figs. 27 – 32; 40 D; 41 F; 42 D; 43 C, 43 D	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E121FFB260D0F9E5FA39FA1C.taxon	materials_examined	Type locality. Lake Baikal, coastal zone of Peschanaya Bay (approximate coordinates: 52 ° 15 ′ 37 N, 105 ° 42 ′ 17 E). Type material. Lectotype No. O 3 (male) and paralectotype No. 1 (female): dwm No. O 1 – 040866. Paralectotypes Nos. 2 – 6 (3 females, 2 males): dwm No. O 2 – 040866. Paralectotypes Nos. 7 – 11 (3 females, 2 males): dwm No. O 3 – 040866. Paralectotypes Nos. 12 – 21 (5 females, 5 males): swm No. x 945. Paralectotypes Nos. 22, 23 (male and female in copula): swm No. x 945. Paralectotype No. 24 (female): swm No. x 945 (valves) and wm No. O 4 – 040866 (limbs). Paralectotype No. 25 (male): swm No. x 945 (valves) and wm No. O 5 – 040866 (limbs). Additional material. Specimens Nos. 1 – 3 (two females, one male): swm No. x 964 (valves). All specimens were collected in Lake Baikal, southern basin, in coastal zone of Peschanaya Bay, August 4, 1966, depth 18 – 20 m, sand, sample No. 13 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E121FFB260D0F9E5FA39FA1C.taxon	description	Description. Female. Carapace (Fig. 27 A – 27 D; 28 A – 28 F; 40 D) laterally broadly trapezoidal; L = 930 – 990 µm (average 955 µm, n = 6), greatest H = 555 – 580 µm (average 570 µm, n = 6) located on posterior border of 1 / 4 L. Dorsal margin straight, anterior margin widely rounded, posterior margin rounded-angular. LV overlaps RV throughout. Ventral margin of valves on inner side is more concave than on outer side. Inner lamella broad, marginal pore canals occupy 80 – 100 % of width of inner lamella. Inner lamella of each valve with 50 – 70 marginal pore canals. Sensillae of outer lamella relatively sparse and emerging from small outgrowths. Microrelief of valve surface relatively homogenous, consisting of large cells (Fig. 30 D). Diameter of cells larger in center of carapace and slightly smaller at margins of valves (Fig. 30 A, 30 B). Site of greatest width (both on ventral and dorsal sides) at 2 / 3 L of carapace. A 1 (Fig. 31 A) seven-segmented. First segment with one finely plumed seta. Second segment with three setae, two of same length, one shorter and finely plumed. Third segment with one seta. Fourth segment with two small setae. Fifth segment with two setae of different lengths. Sixth segment with four setae of different lengths and one claw. Seventh segment with two claws of different lengths, one seta and stick-shaped aesthetasc (ya). A 2 (Fig. 31 B – 31 D). 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. Basal segment with one ventro-distal seta. Exopod with three setae (one of them plumose distally to base). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y) and two posterodistal setae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae of different lengths (t 1 thick and plumose, t 2 slightly shorter and smooth), three z-setae (z 1 three times shorter than z 2 and four times shorter than z 3), three G-claws (G 1 and G 3 two times long G 2), and small distal aesthetasc (y 2). Terminal segment with two G-claws of nearly equal length (GM and Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 31 G). 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: S 1 (long, plumose), S 2 (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 small pseudochaetae. Distal segment with two claws, three setae, and group of small 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 four plumose setae. Distal segment with two claws and seta apically and three setae medially (two plumose and one smooth). Branchial plate with 23 setae and row of pseudochaetae. L 5 (Fig. 32 C – 32 E). Protopod with three setae (a, b, d). Endite with 14 setae, arranged in two groups of four and ten setae. Palp with three setae. Branchial plate reduced to two setae of different lengths. L 6 (Fig. 32 A). Five-segmented. First segment with d 1 - seta. Second and third segments with one distal seta (e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 32 B) four-segmented. First segment with anterior d 1 - seta and posterior dp-seta; d 2 - seta absent. Second segment without pseudochaetae. Third segment with one posterodistal g-seta and rows of pseudochaetae. Fourth segment with three serrate setae (h 1 – h 3) of different lengths. UR (Fig. 32 H). Symmetrical, with smoothly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta, and two thin distal claws of nearly equal length. Male. Carapace (Figs. 27 E – 27 H; 29 A – 29 F; 40 D) laterally broadly trapezoidal, as large as that of female; L = 940 – 990 µm (average 955 µm, n = 5), greatest H = 565 – 595 µm (average 575 µm, n = 5). Site of greatest H at 3 / 4 of L and more pronounced than in female. Dorsal margin slightly inclined towards the anterior end of body. Anterior margin widely rounded; posterior margin rounded more smoothly. Ventral margin of each valve with two triangular projections: one in central part of L, second in posterior 1 / 3 of L. Length of anterior projections 25 – 30 µm, width of their bases 85 – 120 µm; length of posterior projection on RV 50 µm, and on LV 20 µm, width of their bases 90 – 100 µm. Projections arranged symmetrically, main axis directed toward the posterior end of body and slightly toward the opposite valve (Fig. 30 C). Microrelief of carapace, A 1, A 2 (protopod, exopod, first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 31 E, 31 F). Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), two t-setae (t 1, t 2) of different lengths, three z-setae (z 2 and z 3 of almost equal length, and z 1 modified into claw), three G-claws (G 1 and G 2 2.5 times long G 3), and small distal aesthetasc (y 2). Terminal segment with two G-claws (GM and Gm; Gm longer than GM) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 32 F, 32 G) almost symmetrical, crescent-shaped. Main axis of palps arcuately curved distally to insertion of two setae. Left palp with outgrowth in form of “ ear ”. Distal tip of both palps with thin seta. Hemipenis (Fig. 41 F) small, oval-rectangular, 315 µm long and 185 µm wide; lobes oval, weakly protruding. Zenker organ (Fig. 42 D) 315 µm long, with 4 + 2 rings of spines 85 µm in diameter, diameter of central tube 35 µm, vesicle large, 90 µm in diameter. UR (Fig. 32 I) as in female, but rami thinner. Comparisons. P. glauci is clearly distinguished from most Baikalian representatives of the genus by the appearance of the ventral margins of the valves of males, which are armed with four projections (two on each valve). Similar projections are present in males of Pseudocandona academica Mazepova, 1982, but this species is clearly different in the shell’s outline and the morphology of its appendages. Notes. Similar to the previous species, G. F. Mazepova did not designate a holotype, but only indicated paratypes (Mazepova 2001: p. 529), which are not valid without designation of a holotype and should be considered as syntypes, which was undertaken in the present work. Males and females in copula were found (Fig. 43 C, 43 D). The valves of the male grasp the posteroventral margin of the female's shell by outgrowths on the ventral margin of the valves. Geographic distribution. Endemic to Lake Baikal, found in all three basins, on the Ushkany Islands and in the Maloye More Strait at depths of 5 – 20 m on silted sand, and sandy and stony substrates (Mazepova 1990: p. 181).	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E12AFFAE60D0FA0CFC7DFE50.taxon	description	Figs. 33 – 39; 40 F; 41 A; 42 F; 43 E	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E12AFFAE60D0FA0CFC7DFE50.taxon	materials_examined	Type locality. Lake Baikal, east coast of Olkhon Island, coastal zone opposite Izhimey Cape (approximate coordinates: 53 ° 13 ′ 55 N, 107 ° 44 ′ 13 E). Type material. Lectotype No. O 4 (male) and paralectotype No. 1 (female): dwm No. O 12 - 260969. Paralectotypes Nos. 2 – 8 (4 females, 3 males): dwm No. O 13 - 260969. Paralectotypes Nos. 9 – 14 (4 females, 2 males): dwm No. O 18 - 260969. Paralectotypes Nos. 15 – 22 (4 females, 4 males): swm No. x 944. Paralectotype No. 23 (female): swm No. x 944 (valves) and wm No. O 14 - 260969 (limbs). Paralectotype No. 24 (male): swm No. x 944 (valves) and wm No. O 15 - 260969 (limbs). Additional material. Specimens Nos. 1 – 4 (2 females, 2 males): swm No. x 964. Specimen No. 5 (female): swm No. x 964 (valves) and wm No. O 16 - 260969 (limbs). Specimen No. 6 (male): swm No. x 964 (valves) and wm No. O 17 - 260969 (limbs). Specimens Nos. 7, 8 (males): swm No. x 970. All specimens were collected in Lake Baikal, middle basin, east coast of Olkhon Island, in the coastal zone opposite Izhimey Cape, September 26, 1969, depth 90 m, fine-grained sand, sample No. 228 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E12AFFAE60D0FA0CFC7DFE50.taxon	description	Description. Female. Carapace (Figs. 33 A – 33 D; 34 A – 34 F; 40 F) trapezoidal; L = 1870 – 1950 µm (average 1920 µm, n = 9), greatest H = 1180 – 1210 µm (average 1195 µm, n = 9) located on border of anterior 1 / 4 of L. Dorsal margin straight, slightly inclined toward the posterior end, anterior margin widely rounded, posterior margin slightly sloping. Dorsal margin of LV with small keel (Fig. 34 E). LV overlaps RV throughout. Ventral margin of valves straight on outer side and smoothly concave on inner side. Inner lamella broad, marginal pore canals short and occupying 20 – 50 % of inner lamella width. Inner lamella of each valve with 65 marginal pore canals. Sensillae of outer lamella relatively sparse and emerging from small smoothed outgrouths (Fig. 36 I). Microrelief of valve surface heterogenous: in central part it consists of shallow rounded pits with smooth margins (Fig. 36 H), dorsal and ventral margins without pits. On ventral and dorsal margins microrelief in form of hemispheres (Fig. 36 A – 36 D), on dorsal side hemispheres are smaller (Fig. 36 G). Site of greatest width (both ventrally and dorsally) in center of L of carapace. A 1 (Fig. 37 B) eight-segmented. First segment with one seta. Second segment with three setae. Third and fourth segments with one seta each. Fifth and sixth segments with three setae each. Seventh segment with five setae, one of them very small. Eighth segment with three setae and aesthetasc (ya). A 2 (Fig. 38 A, 38 C, 38 D) 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. Basal segment with one ventro-distal seta. Exopod with three setae (one of them plumose distally to base). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y) and two posterodistal setae. Second endopodal segment with one ventromedial seta, small dorsal-medial aesthetasc (y 1), four t-setae (t 1 – t 4) of different lengths, three z-setae (z 1 short, z 2 and z 3 of similar length), three G-claws (G 2 three times shorter than G 1 and G 3), and small distal aesthetasc (y 2). Terminal segment with two G-claws (GM and Gm; GM longer than Gm), two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 37 A). 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: S 1 (long, plumose), S 2 (short, pappose), α (short and thin), and proximal seta. Second segment with six posterior setae (β-seta very small), two anterior setae, and two rows of pseudochaetae. Third segment with four posterodistal setae (γ-seta long and plumose), three anterior setae, and rows of pseudochaetae. Distal segment with two claws, three setae, and group of small 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 finely plumose seta. Distal segment with two claws and seta apically and three setae medially (two plumose and one smooth). Branchial plate with 23 setae and large number of separate groups of long pseudochaetae over entire surface of plate and long row of pseudochaetae. L 5 (Fig. 39 E, 39 F). 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 rows of pseudochaetae. Branchial plate in form of two setae of different lengths. L 6 (Fig. 39 A, 39 B) five-segmented. First through third segments with one distal seta (d 1, e, f) each and rows of small pseudochaetae. Fourth segment with two distal g-setae of different lengths and rows of small pseudochaetae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 39 C, 39 D) five-segmented. First segment with anterior d 1 - seta, posterior dp-seta; d 2 seta absent. Second segment with rows of pseudochaetae. Third segment without pseudochaetae. Fourth segment with posterodistal g-seta and rows of pseudochaetae. Fifth segment with three serrate setae (h 1 – h 3). UR (Fig. 39 I) symmetrical, with smoothly curved main axis. Each ramus with one posterior seta distal to midramus, one short anterodistal seta, and two thin distal claws of nearly equal length. Male. Carapace (Figs. 33 E – 33 H; 35 A – 35 F; 40 F) trapezoidal, slightly longer and lower than in female; L = 1920 – 2000 µm (average 1960 µm, n = 6), greatest H = 1140 – 1170 µm (average 1160 µm, n = 6) located on border of anterior 1 / 4 of L. Ventral margin of each valve with small conical projection (Fig. 36 E, 36 F), main axis of projections slightly directed posteriorly and towards the opposite valve. Shape and size of projections on RV and LV almost identical (projection on RV slightly narrower; Fig. 36 E), length 85 – 115 µm, width of bases 115 – 150 µm. Microrelief as in female, but hemispheres on ventral side are smoothed near conical projections. Other morphological features of carapace structure, A 1, A 2 (protopod, exopod, first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7 as in female. A 2 (Fig. 38 B, 38 E, 38 F). Second endopodal segment with one anteromedial seta, small dorso-medial aesthetasc (y 1), two t-setae (t 1 – t 2) of similar length, three z-setae (z 1 seta short, z 3 seta long, and z 2 modified into long serrated claw), three G-claws (G 3 thin, 2 times shorter than G 1, and almost 3 times shorter than G 1), and distal aesthetasc (y 2). Terminal segment with two G-claws (GM and Gm; Gm longer than GM) and two setae, one of them basally fused with aesthetasc (y 3). Prehensile palps of L 5 (Fig. 39 G, 39 H) asymmetrical, finger-shaped, thickened. Main axis of palps smoothly curved distally to the site of insertion of two setae; setae on both palps short and thick. Distal tip of both palps with thick seta. Hemipenis (Fig. 41 A) large, irregularly rounded-rectangular, 715 µm long and 340 µm wide (including lobes); lobes ovoid, strongly protruding. Zenker organ (Fig. 42 F) 435 µm long, with 5 + 2 rings of spines 190 µm in diameter, diameter of central tube 75 µm, vesicle large, 145 µm in diameter. UR (Fig. 39 J) as in female, but main axis straighter. Comparisons. The species is clearly distinguished from other Baikalian representatives of the genus by a large size, shell shape and conical ventral projections on the male valves. The structure of the A 1 and A 2 of both sexes and the male L 5 prehensile palps, as well as the reproductive system (large hemipenes and Zenker organs with seven rosettes), allow this species to be distinguished from others. Notes. When describing the species, Prof. G. F. Mazepova did not designate a holotype, but only indicated paratypes (Mazepova 2001: p. 535), which are not valid without designation of the holotype and should be considered as syntypes, which was undertaken in the present work. Females and males in copula were found (Fig. 43 E). Geographic distribution. Endemic to Lake Baikal, found in Aya Bay (depth 50 m); at capes Yador, Onguren and Koltygey; opposite Izhimey Сape (Olkhon Island); at the eastern coast of the lake (exact location not indicated) found at a depth of 300 m. Lives on silted sand (Mazepova 1990: p. 254).	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E136FFA160D0FDC0FE44FA34.taxon	description	Figs. 44 – 48	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E136FFA160D0FDC0FE44FA34.taxon	materials_examined	Type locality. Lake Baikal, coastal zone opposite Elokhin Cape (approximate coordinates: 54 ° 32 ′ 42 N, 108 ° 39 ′ 42 E). Type material. Holotype No. O 21 (male) and allotype No. O 21.1 (female): dwm No. O 3 - 200776. Paratypes Nos. 1 – 35 (12 females, 23 males): dwm No. O 4 - 200776. Paratypes Nos. 36 – 41 (three pairs of females and males in copula): dwm No. O 5 - 200776. Paratypes Nos. 42 – 50 (four females, five males): swm No. 51. Paratype No. 51 (female): swm No. 51 (valves) and wm No. O 6 - 200776 (limbs). Paratype No. 52 (female): swm No. 51 (valves) and wm No. O 7 - 200776 (limbs). Paratype No. 53 (male): swm No. 51 (valves) and wm No. O 8 - 200776 (limbs). Paratype No. 54 (male): swm No. 51 (valves) and wm No. O 9 - 200776 (limbs). Paratype No. 55 (male): swm No. 51 (valves) and wm No. O 10 - 200776 (limbs). Paratype No. 56 (male): swm No. 51 (valves and Zenker organ). Paratypes Nos. 57 – 60 (two pairs of females and males in copula): swm No. 51. Paratypes Nos. 61, 62 (two males): swm No. 51. All specimens were collected in Lake Baikal, northern basin, in the coastal zone opposite Elokhin Cape, July 20, 1976, depth 5 m, sand with algae (genus Draparnaldia Bory de Saint-Vincent, 1808), sample No. 743 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E136FFA160D0FDC0FE44FA34.taxon	etymology	Etymology. The name of the species comes from the word “ geminatus ” (Latin) – double, paired and is associated with the identical location of two small ventral projection on the male carapaces.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E136FFA160D0FDC0FE44FA34.taxon	description	Description. Female. Carapace (Figs. 44 E – 44 H; 45 A – 45 F; 48 A, 48 B) trapezoidal; L = 960 – 1015 µm (average 985 µm, n = 10), greatest H = 570 – 600 µm (average 580 µm, n = 10) located slightly anteriorly to anterior 1 / 3 of L. Dorsal margin straight, anterior margin widely rounded, posterior margin in form of obtuse angle. LV overlaps RV throughout. Ventral margin of both valves less concave on outer side than on inner side. Inner lamella broad, marginal pore canals occupy 70 – 100 % of inner lamella width. Inner lamella of each valve with at least 40 – 45 marginal pore canals. Sensillae of outer lamella relatively sparse. Microrelief of valve surface homogenous (Fig. 47 A), consisting of cells. Diameter of cells larger in center and slightly smaller at margins of valves. Site of greatest width (both ventrally and dorsally) slightly behind center L of carapace. A 1, A 2, Md, Mxl, L 5, L 7, and UR as in female P. glauci. Male. Carapace (Figs. 44 A – 44 D; 46 A – 46 H; 48 C, 48 D) trapezoidal, slightly shorter and lower than in female; L = 910 – 960 µm (average 925 µm, n = 10), greatest H = 520 – 570 µm (average 550 µm, n = 10) located slightly behind posterior 1 / 3 of L. Dorsal margin straight, slightly inclined toward anterior end, anterior margin rounded, posterior end slightly sloping, without distinct angle region as in female. Ventral margin of carapace with two symmetrical projections (one on each valve, Fig. 47 B – 47 E), which located slightly behind center of L, in posterior part of ventral concavity. Length of projections 40 – 50 µm, base width 50 – 60 µm. Main axis of both projections directed backwards and slightly towards opposite valve. Central part of ventral margin of valves on inner side more concave than in female. Dorsally and ventrally, carapace narrower than in female, site of greatest width expressed less clearly. Other morphological features of carapace structure, A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7 as in female. Second and third endopodal segments of A 2 and UR as in male P. glauci. Prehensile palps of L 5 (Fig. 48 G, 48 H) almost symmetrical, crescent-shaped and resembling palps of P. glauci male, but curved more sharply, and distal end of left palp noticeably wider. Hemipenis (Fig. 48 E) rounded-rectangular, 305 µm long and 180 µm wide; lobes oval, weakly protruding. Zenker organ (Figs. 47 H; 48 F) 285 µm long, with 4 + 2 rings of spines 100 µm in diameter, diameter of central tube 43 µm, vesicle large, 75 µm in diameter. Comparisons. The carapace and soft body morphologies of males and females of P. geminata sp. nov. are very similar to those of P. glauci. There are two symmentrically located projections (one on each valve) on the ventral side of the male carapace of the new species, while P. glauci males have four ventral projections (two on each valve). Comparions of the valve outlines of the male and female individuals demonstrate differences of the posterior margin. It is clearly seen in SEM images of the inner side of the valves: the posterior margin of P. glauci females is more rounded (Fig. 28 E, 28 F), whereas this margin has a well-defined angle in females of the new species (Fig. 45 E, 45 F). The shape of the posterior valve margin of the males (besides ventral projections) is different: it is more rounded in P. glauci (Fig. 29 E, 29 F), and more angular in P. geminata sp. nov. (Fig. 46 E, 46 F). The inner side of the ventral margin of males of the new species is more concave than in males of the previously described species. The prehensile palps of the L 5 of P. geminata sp. nov. males differ from P. glauci male palps by a sharper curve of the main axis and a wider distal part of the left palp (Figs. 32 F, 32 G; 48 G, 48 H). Hemipenes of the species compared show a similar morphology, but the outer lobe of the new species is somewhat longer. Judging by the females and males during copulation, the species mate in various positions: P. glauci males grasp the ventro-posterior tip of the female shell with four ventral projections (Fig. 43 C, 43 D), but P. geminata sp. nov. males fix much higher on the posterior margin (Fig. 47 F, 47 G). Geographic distribution. Endemic to Lake Baikal, found in the coastal zone opposite Elokhin Cape (depth 5 m). Lives on sand with algae.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E139FFA460D0FA3FFC61FCDC.taxon	description	Figs. 49 – 52; 53 A; 54; 55; 56 C; 74 A; 75 C, 75 G	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E139FFA460D0FA3FFC61FCDC.taxon	materials_examined	Type locality. Lake Baikal, coastal zone opposite the Zhilishche Valley, opposite the LIN SB RAS station (approximate coordinates: 51 ° 53 ′ 55 N, 105 ° 03 ′ 49 E). Type material. Holotype No. O 17 (female) and allotype No. O 17.1 (male): dwm No. O 1 - 170869. Paratypes Nos. 1 – 3 (2 females, male): dwm No. O 2 - 170869. Paratypes Nos. 4 – 12 (5 females, 4 males): swm No. 43. Paratype No. 13 (female): swm No. 43 (valves) and wm No. O 3 - 170869 (limbs). Paratype No. 14 (female): swm No. 43 (valves) and wm No. O 4 - 170869 (limbs). Paratype No. 15 (female): swm No. 43 (right valve) and wm No. O 5 - 170869 (limbs). Paratype No. 16 (male): swm No. 43 (valves) and wm No. O 6 – 170869 (limbs). Paratype No. 17 (male): swm No. 43 (valves) and wm No. O 7 - 170869 (limbs). Paratype No. 18 (male): swm No. 43 (left valve) and wm No. O 8 - 170869 (limbs). All specimens were collected in Lake Baikal, southern basin, in the coastal zone opposite Zhilishche Valley, opposite the LIN SB RAS station, August 17, 1969, depth 114 m, conglomerates, sample No. 204 from the collection of G. F. Mazepova.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E139FFA460D0FA3FFC61FCDC.taxon	etymology	Etymology. The name of the species comes from the word “ concavus ” (Latin) – concave, curved and refers to the morphology of the ventral margin of the valves.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E139FFA460D0FA3FFC61FCDC.taxon	description	Description. Female. Carapace (Figs. 49 A – 49 D; 50 A – 50 F; 56 C; 74 A) laterally crescent-shaped; L = 1170 – 1195 µm (average 1185 µm, n = 6), greatest H = 495 – 520 µm (average 505 µm, n = 6) located slightly anteriorly to center of L. Dorsal margin smoothly arcuate. Anterior margin broadly rounded near ventral margin, posterior margin pointed near ventral margin. Ventral margin distinctly concave on 2 / 3 of L. LV barely overlaps RV throughout. Inner lamella relatively broad, especially in anterior and posterior parts of valves. Marginal pore canals in anterior and posterior parts of valves occupy about 15 – 70 % of width of inner lamella (Fig. 52 D, 52 E). Inner lamella of each valve of same individual with at least 100 – 105 marginal pore canals. Sensillae of outer lamella relatively sparse, but numerous in anterior and posterior parts of ventral margin (Fig. 52 A, 52 C), emerging from unbordered pores (Fig. 52 B). Valve surface smooth and homogenous. Site of greatest width (both ventrally and dorsally) weakly defined and located in anterior 1 / 3 of L. A 1 (Fig. 54 A) eight-segmented. First segment with one seta. Second segment with three setae. Third and fourth segments with one seta each. Fifth segment with one long seta and one short seta. Sixth segment with one long seta. Seventh segment with five setae (two long, two medium and one short). Eighth segment with three setae (two long, one half as long) and stick-shaped aesthetasc (ya). A 2 (Fig. 54 B, 54 C) five-segmented. Coxal segment with three smooth setae, one of them on this segment proper, two located between coxal and basal segments. Basal segment with one ventro-distal seta. Exopod with three smooth setae. Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posterodistal setae of different lengths, and row of pseudochaetae. Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), two t-setae (t 1, t 2); three z-setae (z 1 – z 3) of almost equal length; three G-claws (G 2 small and six times shorter than G 1 and G 3) and distal aesthetasc (y 2). Terminal segment with two G-claws (GM slightly longer than Gm; Gm a thin seta) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 53 A). Coxa with one subapical seta and one seta on apical inner angle. Apparently, no setae between teeth of endite. Branchial plate with seven plumose setae and one smooth seta. Palp four-segmented. First segment with four setae: S 1 (long, plumose), S 2 (relatively long, pappose), α (thin and relatively long) and proximal seta. Second segment with six posterior setae (β-seta relatively long) and two anterior setae. Third segment with four posterodistal setae (γ-seta small, smooth) and three anterior setae. Distal segment with two claws of equal length and two setae. Mxl. Protopod without setae. First endite with 14 setae, two at base of endite, 12 at apex. Second endite with nine setae. Third endite with eight setae and two claws. Palp two-segmented; first segment with four setae. Distal segment with two claws and seta apically and three setae medially. Branchial plate with 23 setae and row of long pseudochaetae. L 5 (Fig. 55 A). Protopod with three setae (a, b, d). Endite with 14 setae, arranged in two groups of four and ten setae, respectively. Palp with three setae. Branchial plate represented by two setae of different lengths. L 6 (Fig. 55 D) five-segmented. First through third segments with distal seta (d 1, e, f) each; first segment with rows of pseudochaetae. Fourth segment with two small distal g-setae. Fifth segment with long claw (h 2) and two small setae (h 1 and h 3) of different lengths. L 7 (Fig. 55 E) five-segmented. First segment with anterior d 1 - seta, posterior dp-seta and rows of small pseudochaetae; d 2 seta absent. Second and third segments without pseudochaetae. Fourth segment with posterodistal g-seta. Fifth segment with three serrate setae (h 1 – h 3). UR (Fig. 55 F) symmetrical, with slightly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta and two slender distal claws of nearly equal length. Male. Carapace (Figs. 49 E – 49 H; 51 A – 51 F; 74 A) laterally crescent-shaped, shorter and lower than in female; L = 1140 – 1170 µm (average 1150 µm, n = 6), greatest H = 480 – 500 µm (average 490 µm, n = 6). Center of ventral concavity with slight convexity on both valves (Fig. 51 B, 51 C, 51 E) compared to that of female (Fig. 50 B, 50 C, 50 E). Other morphological features of carapace, A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7, as in female. A 2 (Fig. 54 D – 54 G) six-segmented (four-segmented endopod). Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), three t-setae (t 2 and t 3 modified into sensory setae with oval ends). Third endopodal segment with three z-setae (z 1 – z 3) of equal length, three G-claws (G 2 2.5 times longer than G 1 and G 3) and distal aesthetasc (y 2). Terminal segment with long Gm-claw, shorter GM-claw in form of seta, and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 55 B, 55 C) asymmetrical. Both palps wide and thick proximally to site on insertion of two setae, sharply curved distally: left palp crescent-curved towards body, and right palp curved in opposite direction. Distal tip of both palps with short and thick seta. Hemipenis (Fig. 75 C) large, rectangular, 305 µm long and 120 µm wide; lobes oval, weakly protruding. Zenker organ (Fig. 75 G) 310 µm long, with 5 + 2 rings of spines 90 µm in diameter, diameter of central tube 30 µm, vesicle large, 85 µm in diameter. UR (Fig. 55 G) as in female, but main axis straighter, posterior claw slightly shorter. Comparisons. The carapace of the individuals of the new species is structurally similar to Candona memoranda Mazepova, 1990 (Fig. 56 A); both species have similar valve outlines and shapes of the ventral margin. C. memoranda shells are remarkably lower (mean H of females 415 µm, males – 400 µm) than the shell height of the new species (mean H of females 505 µm, males – 490 µm), and the shell L / H ratio of C. memoranda (females – 3.05, males – 2.96) is higher than in C. concava sp. nov. (females and males – 2.35). The valves of the species compared differ in the structure of the inner lamella, particularly the posterior part. The male individuals show differences in the structure of the L 5 prehensile palps and hemipenes. Notes. Valve outlines of the new species are very close to those of Candona godlewskii Mazepova, 1984 sensu Karanovic & Sitnikova (2017) (Fig. 56 D). It seems likely that they belong to related species. In the authors’ view, C. godlewskii sensu Karanovic & Sitnikova (2017) (Fig. 56 D) and C. godlewskii sensu Mazepova (1984) (Fig. 56 B) are different species. For reliable comparisons, we present SEM images of the shell of C. godlewskii sensu Mazepova (1984) syntype (Fig. 56 B). It is evident that these individuals have different valve shapes (Fig. 56 B, 56 D). According to the valve images and description, the microrelief of C. godlewskii sensu Karanovic & Sitnikova (2017) is pitted in the center of the valves (Karanovic & Sitnikova 2017: p. 29: Fig. 4 C). After examining SEM images of the lateral view of the valves (Karanovic & Sitnikova 2017: p. 29: Fig. 4 A, 4 B) it appears that their microrelief is not pitted. Judging by the microphotographs of an enlarged valve (Karanovic & Sitnikova 2017: p. 29: Fig. 4 C), it may be suggested that these microphotos show Candona rupestris dissona Mazepova, 1990 (= Baicalocandona rupestris disona (Mazepova, 1990) Karanovic & Sitnikova 2017) from the same work (Karanovic & Sitnikova 2017: p. 39: Fig. 12 E). However, it is still possible that individuals of C. godlewskii sensu Karanovic & Sitnikova (2017) studied actually had a microrelief, since it is mentioned in the valve description. In such a case, the microrelief is a significant distinctive feature of C. godlewskii sensu Karanovic & Sitnikova (2017), and different from the new species. Geographic distribution. Endemic to Lake Baikal, found in the coastal zone opposite the Zhilishche Valley, opposite the LIN SB RAS station (depth 114 m). Lives on conglomerates.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E13CFFD360D0FC41FA8EFF54.taxon	description	Figs. 53 B; 57 – 61; 74 B; 75 B, 75 F	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E13CFFD360D0FC41FA8EFF54.taxon	materials_examined	Type locality. Lake Baikal, east coast of Olkhon Island, coastal zone of Khurai-Khalzyn Bay (53 ° 02 ′ 30 N, 107 ° 04 ′ 11 E). Type material. Holotype No. O 18 (female) and allotype No. O 18.1 (male): dwm No. O 1 - 080624. Paratypes Nos. 1, 2 (two males): dwm No. O 2 - 080624. Paratypes Nos. 3, 4 (female and male): swm No. 46. Paratype No. 5 (female): swm No. 46 (valves) and wm No. O 3 - 080624 (limbs). Paratype No. 6 (male): swm No. 46 (valves) and wm No. O 4 - 080624 (limbs). Paratype No. 7 (male): swm No. 46 (valve fragments) and wm No. O 5 - 080624 (limbs). Paratypes Nos. 8 – 12 (2 females, 3 males): dwm No. O 1 - 180625. Holotype, allotype and paratypes Nos. 1 – 6 were collected in Lake Baikal, middle basin, eastern coast of Olkhon Island, in the coastal zone of Khurai-Khalzyn Bay, June 8, 2024, depth 0.3 m, stone with algae; paratype No. 7 was collected at the same locality and on the same date, but at a depth of 2 m, sand between stones. Paratypes Nos. 8 – 12 were collected at the same locality on June 18, 2025, depth 0.5 m, stone with algae.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E13CFFD360D0FC41FA8EFF54.taxon	etymology	Etymology. The species is named in honor of Anastasia Gennadievna Koroleva (Limnological Institute SB RAS, Irkutsk, Russia), a molecular biologist, specialist in the biology of telomeres of Baikalian hydrobionts and an excellent teacher.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E13CFFD360D0FC41FA8EFF54.taxon	description	Description. Female. Carapace (Figs. 57 A – 57 D; 58 A, 58 B, 58 E; 74 B) laterally kidney-drop-shaped; L = 630 – 650 µm (average 640 µm, n = 3), greatest H = 335 – 350 µm (average 345 µm, n = 3) located on border of posterior 1 / 3 of L. Dorsal margin smoothly arcuate. Anterior margin of valves widely rounded near ventral margin, posterior margin slightly sloping, drawn into an acute angle. Ventral margin smoothly curved on outer and inner sides. LV slightly overlaps RV throughout. Inner lamella relatively broad, especially in posterior part of valves. Marginal pore canals occupy 15 – 40 % of width of inner lamella in anterior and posterior parts of valve. Inner lamella of each valve of same individual with at least 60 – 65 marginal pore canals. Sensillae of outer lamella relatively sparse and emerge from bordered pores. Microrelief over most of carapace smooth and homogenous. Posterior margin covered with “ knitted ” microrelief (Fig. 59 A – 59 C), which consists of individual elements of rounded or polygonal shape. Center of these individual elements is smooth, and perimeter covered with grooves and elevations directed towards center (Fig. 59 D – 59 G). Microrelief smooths out with distance from posterior margin and is replaced by shallow grooves forming rhomboid structures, which then become completely smooth. Site of greatest width (both ventrally and dorsally) poorly defined and located in central part of carapace. Carapace of living specimens is brown and does not lose its color for at least several months when preserved in ethanol. A 1 (Fig. 60 A) seven-segmented. First segment with one plumose seta. Second segment with three setae. Third segment with one seta. Fourth segment with two setae. Fifth segment with one short seta and two long setae. Sixth segment with two claws of different lengths, two long setae and one short seta. Seventh segment with one claw, two setae of different lengths and stick-shaped aesthetasc (ya). A 2 (Fig. 60 B – 60 E) five-segmented. Coxal segment with three setae, one of them inserted on this segment, two located between coxal and basal segments. One of them small and pappose. Basal segment with one ventro-distal seta. Exopod with two short smooth setae and one long seta. Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y) and two posterodistal setae of almost equal length. Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), three t-setae (t 1 two times longer than t 2 and t 3); three z-setae (z 1 – z 3); three G-claws (G 1 – G 3) of nearly equal length and distal aesthetasc (y 2). Last segment with two G-claws (GM and Gm; GM longer than Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 53 B). 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: S 1 (long, plumose), S 2 (short, pappose), α (small and short) and proximal seta. Second segment with six posterior setae (β-seta small) and two anterior setae. Third segment with four posterodistal setae (γ-seta large, plumose) and three anterior setae. Distal segment with two claws of equal length and two setae (one of them very small). Mxl. Protopod without setae. First endite with 14 setae, two at base of endite, 12 at apex. Second endite with nine setae. Third endite with eight setae and two claws. Palp two-segmented; first segment with four setae. Distal segment with two claws and seta apically and three setae medially. Branchial plate with 23 setae and long row of pseudochaetae. L 5 (Fig. 61 A). 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 rows of small pseudochaetae. Branchial plate represented by two setae of different lengths. L 6 (Fig. 61 D) five-segmented. First through third segments with distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two setae (h 1 and h 3) of different lengths. L 7 (Fig. 61 E) four-segmented. First segment with anterior d 1 - seta, posterior dp-seta and rows of small pseudochaetae; d 2 seta absent. Second segment without pseudochaetae. Third segment with posterodistal g-seta. Fourth segment with three serrate setae (h 1 – h 3), all of different lengths. UR (Fig. 61 F) symmetrical, with smoothly curved main axis, wide and tapering distally. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta and two distal claws of different lengths. Male. Carapace (Fig. 57 E – 57 H; 58 C, 58 D, 58 F; 74 B) laterally kidney-shaped, same size as female; L = 625 – 650 µm (average 640 µm, n = 5), greatest H = 335 – 350 µm (average 340 µm, n = 5). Posterior margin rounded compared to that in female. Small acute-angled outgrowth in anterior part of ventral margin formed by extension of outer fringe of valves. Inner lamella in posterior part of valves narrower compared to that of female. No microrelief in posterior part in comparison with female. Other morphological features of carapace, A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7, as in female. A 2 (Fig. 60 F – 60 I) six-segmented (four-segmented endopod). Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), four t-setae (t 2 and t 3 modified into sensory setae with oval end, t 1 - seta long, t 4 - seta short). Third endopodal segment with three z-setae (z 1 and z 2 modified into long claws), three G-claws (G 2 two times longer than G 1 and G 3), and distal aesthetasc (y 2). Terminal segment with long Gm-claw, short GM-claw, and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 61 B, 61 C) asymmetrical. Both palps crescent-shaped, curved distally to site of insertion of two setae. Right palp significantly thicker than left. Distal tip of both palps with thin seta. Hemipenis (Fig. 75 B) rectangular, 250 µm long and 135 µm wide (including outer lobe); outer lobe shaped like truncated cone and protrudes strongly. Zenker organ (Fig. 75 F) 215 µm long, with 4 + 2 rings of spines 60 µm in diameter, central tube 25 µm in diameter, vesicle large, 50 µm in diameter. UR (Fig. 61 G) as in female, but rami narrower. Comparisons. Males of the new species remotely resemble males of Candona picta Mazepova, 1990 and Candona virgata Mazepova, 1985 in carapace morphology, but differ in the morphology of the prehenhile palps and hemipenes. Females have a unique valve contour and unique microrelief. Females of C. picta and C. virgata have a slightly sloping posterior margin, but are clearly distinguishable from females of the new species. Notes. In the process of studying the ostracod fauna of Lake Baikal, we discovered at least one more species with a microrelief similar to the females of C. korolevae sp. nov. Geographic distribution. Endemic to Lake Baikal, found on the east coast of Olkhon Island, in the coastal zone of Khurai-Khalzyn Bay (depths of 0.3 – 2 m). Lives on stones with algae and on sand between stones.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E14BFFCB60D0F94CFE5EFA1C.taxon	description	Figs. 62 – 68; 74 C; 75 A, 75 E	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E14BFFCB60D0F94CFE5EFA1C.taxon	materials_examined	Type locality. Lake Baikal, coastal zone of Ayaya Bay (55 ° 27 ′ 19 N, 109 ° 53 ′ 43 E). Type material. Holotype No. O 19 (male) and allotype No. O 19.1 (female): dwm No. O 1 - 130624. Paratypes Nos. 1 – 19 (19 females): dwm No. O 2 - 130624. Paratypes Nos. 20 – 26 (7 females): dwm No. O 3 - 130624. Paratypes Nos. 27 – 34 (4 females, 4 males): swm No. 44. Paratype No. 35 (female): swm No. 44 (valves) and wm No. O 4 - 130624 (limbs). Paratype No. 36 (female): swm No. 44 (valves) and wm No. O 5 - 130624 (limbs). Paratype No. 37 (female): swm No. 44 (valves) and wm No. O 6 - 130624 (limbs). Paratype No. 38 (male): swm No. 44 (valves) and wm No. O 7 - 130624 (limbs). Paratype No. 39 (male): swm No. 44 (valves) and wm No. O 8 - 130624 (limbs). Paratype No. 40 (male): swm No. 44 (valves) and wm No. O 9 - 130624 (limbs). All specimens were collected in Lake Baikal, northern basin, in the coastal zone of Ayaya Bay, June 13, 2024, depth 18 m, sand and stones with algae.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E14BFFCB60D0F94CFE5EFA1C.taxon	etymology	Etymology. The name of the species comes from the word “ lanatus ” (Latin) – covered with wool, woolly and reflects the large number of pseudochaetae covering the limbs of individuals of the species.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E14BFFCB60D0F94CFE5EFA1C.taxon	description	Description. Female. Carapace (Figs. 62 A – 62 D; 63 A – 63 H; 74 C) laterally irregularly oval-trapezoidal; L = 1065 – 1220 µm (average 1145 µm, n = 10), greatest H = 520 – 600 µm (average 570 µm, n = 10). Site of greatest H poorly expressed and located on border of posterior 1 / 3 of L. Dorsal margin smoothly arcuate. Anterior margin of valves widely rounded near ventral margin, posterior margin slightly sloping and smoothly rounded. Ventral margin almost straight on outer and inner sides. LV overlaps RV throughout. Inner lamella relatively narrow, widened in anterior part of valves. Marginal pore canals in anterior and posterior parts of ventral margin occupy 15 – 60 % of width of inner lamella. Inner lamella of each valve of same individual with at least 135 – 140 marginal pore canals. Sensillae of outer lamella relatively sparse, more frequent in anterior and posterior parts of ventral margin, emerging from bordered pores. Outer lamella of each valve of same individual with 170 – 180 pore canals. Microrelief smooth and homogenous. Site of greatest width (both on ventral and dorsal sides) weakly expressed and located in central part of carapace. Carapace of living crustaceans is white-yellow and does not lose its color for at least several months when preserved in ethanol. A 1 (Fig. 67 A) eight-segmented. First segment with one seta and rows of pseudochaetae. Second segment with three setae and row of pseudochaetae. Third segment with one seta and row of pseudochaetae. Fourth segment with one seta. Fifth and sixth segments with two long setae and one short seta each. Seventh segment with three setae (two long, one short) and two claws of different lengths. Eighth segment with two setae of different lengths, one claw and stick-shaped aesthetasc (ya). A 2 (Fig. 65 A – 65 D) five-segmented. Coxal segment with three setae, one inserted on this segment, two located between coxal and basal segments. One of them small and pappose. Basal segment with one ventromedial seta and row of pseudochaetae. Exopod with three setae: two short smooth, one long (smooth or very finely plumed). Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posteromedial setae of almost equal length, and numerous rows of pseudochaetae. Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), four t-setae (t 4 slightly shorter than t 1 – t 3); three z-setae of nearly equal length (z 1 – z 3, z 1 claw-shaped), three G-claws (G 1 – G 3) of nearly equal length, distal aesthetasc (y 2) and rows of pseudochaetae. Terminal segment with two G-claws (GM and Gm; GM slightly longer than Gm) and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 66 A). 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: S 1 (long, plumose), S 2 (relatively long, pappose), α (small and short) and proximal seta. Second segment with six posterior setae (β-seta small), two anterior setae and rows of pseudochaetae. Third segment with four posterodistal setae (γ-seta large, smooth), three anterior setae and rows of long pseudochaetae. Distal segment with two claws of equal length, three setae (one of them very small) and rows of pseudochaetae. Mxl (Fig. 66 B – 66 F). Protopod without setae. First endite with 14 setae, two at base of endite, 12 at apex. Second endite with nine setae. Third endite with eight setae and two claws. Palp two-segmented; first segment with four setae. Distal segment with two claws and seta apically and three setae medially. Branchial plate with 23 setae and long row of pseudochaetae. L 5 (Fig. 68 A). Protopod with three setae (a, b, d) and rows of long pseudochaetae. Endite with 14 setae, arranged in two groups of four and ten setae. Palp with three setae, rows of small and long pseudochaetae. Branchial plate in form of two setae of different lengths. L 6 (Fig. 67 B) five-segmented. First through third segments with distal seta (d 1, e, f) each and rows of pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with long claw (h 2) and two setae (h 1 and h 3) of different lengths. L 7 (Fig. 67 C) five-segmented. First segment with anterior d 1 - seta, posterior dp-seta, and rows of small pseudochaetae; d 2 seta absent. Second segment with rows of small pseudochaetae. Third segment without pseudochaetae. Fourth segment with posterodistal g-seta and rows of small pseudochaetae. Fifth segment with three serrate setae (h 1 – h 3), all of different lengths. UR (Fig. 68 D) symmetrical, with smoothly curved rami. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta, and two distal claws of nearly equal length. Male. Carapace (Figs. 62 E – 62 H; 64 A – 64 H; 74 C) laterally irregularly oval-trapezoidal, longer and higher than in female; L = 1240 – 1285 µm (average 1265 µm, n = 6), greatest H = 675 – 690 µm (average 680 µm, n = 6). Ventral margin of valves slightly more concave than in female. Posterior margin of valves slightly concave. Inner lamella in posterior part of valves slightly wider than in female, with 150 – 155 canals. Other morphological features of carapace, A 1, A 2 (protopod, exopod and first endopodal segment), Md, Mxl, L 5 protopod, L 6, L 7, as in female. A 2 (Fig. 65 E – 65 H) six-segmented (four-segmented endopod). Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), three t-setae (t 2 and t 3 modified into sensory setae with oval ends), and rows of pseudochaetae. Third endopodal segment with three z-setae (z 1 and z 2 modified into long claws), three G-claws (G 2 almost two times longer than G 1 and G 3) and distal aesthetasc (y 2). Terminal segment with long Gm-claw, short GM-claw, and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 68 B, 68 C) asymmetrical. Both palps crescent-shaped, curved distally to site of insertion of two setae. Right palp thicker than left. Distal tip of both palps with short and thick seta. Hemipenis (Fig. 75 A) large, rectangular, 435 µm long and 260 µm wide (including outer lobes); lobes oval, outer lobe protrudes strongly and ends in long and spiny outgrowth. Zenker organ (Fig. 75 E) 380 µm long, with 5 + 2 rings of spines 170 µm in diameter, diameter of central tube 35 µm, vesicle small, 35 µm in diameter. UR (Fig. 68 E) as in female, but anterior seta slightly shorter. Comparisons. Among Baikalian species of the genus, the female carapace shape of the new species is most similar to that of Candona modesta Mazepova, 1984. Female shells of C. modesta are distinguished by a more pronounced site of the greatest H and a significantly lower width in dorsal view (length / width ratio – 3.35, length / width ratio of the new species – 2.5). Average length and height of female valves of the new species (L = 1145 µm, H = 570 µm) are remarkably greater than in C. modesta (L = 830 µm, H = 410 µm). Available illustrations of C. modesta (Mazepova 1990: p. 113, Fig. 39) show that the e-seta of the L 6 is noticeably shorter than the third segment, while the e-seta of C. lanata sp. nov. is longer than the third segment; and the A 1 setae are significantly longer. In particular, a long distal A 1 seta of the individuals of C. lanata sp. nov. is five times longer that the terminal segment, whereas it is at least eight times longer than the terminal segment in C. modesta. The posterior UR seta of C. modesta females is half as long as the claws, while the UR claws and setae of the new species have similar lengths. C. modesta males have not been described so far, the type material was not identified and is absent in the ostracod collection of G. F. Mazepova (2001). C. modesta specimens were found from the mouth of the Angara River (southern basin of Lake Baikal) up to Maloye More Strait (Mazepova 1990: pp. 113, 114), and the individuals of the new species in the northern basin, in Ayaya Bay (marked as possibly occurring in the nearshore of Frolikha Bay). Geographic distribution. Endemic to Lake Baikal, found in the coastal zone of Ayaya Bay (depth 18 m). Lives on sand and stones with algae.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E153FFC360D0FA01FE7CFD70.taxon	description	Figs. 53 C, 69 – 73; 74 D; 75 D, 75 H	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E153FFC360D0FA01FE7CFD70.taxon	materials_examined	Type locality. Lake Baikal, coastal zone of Dagarskaya Bay (55 ° 39 ′ 10 N, 109 ° 54 ′ 47 E). Type material. Holotype No. O 20 (female): dwm No. O 1 - 200924. Allotype No. O 20.1 (male): swm No. 45 (valves) and wm No. O 2 - 200924 (limbs). Paratypes Nos. 1 – 4 (4 females): swm No. 45. Paratype No. 5 (female): swm No. 45 (valves) and wm No. O 3 - 200924 (limbs). Paratype No. 6 (female): dwm No. O 4 - 200924. Additional material. Juvenile stage No. 1: swm No. 45. All specimens were collected in Lake Baikal, northern basin, in the coastal zone of Dagarskaya Bay, September 20, 2024, depth 12 m, sand with detritus.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E153FFC360D0FA01FE7CFD70.taxon	etymology	Etymology. The name of the species comes from the word “ perforatus ” (Latin) – perforated, covered with holes, indicating the distinctive microrelief of the valve surface.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
0392A331E153FFC360D0FA01FE7CFD70.taxon	description	Description. Female. Carapace (Figs. 69 A – 69 D; 70 A – 70 F; 74 D) laterally elongated-trapezoidal; L = 750 – 780 µm (average 760 µm, n = 6), greatest H = 415 – 425 µm (average 420 µm, n = 6) located on border of posterior 1 / 4 of L. Dorsal margin almost straight. Anterior margin of valves widely rounded near ventral margin, posterior margin slightly sloping, smoothly rounded. Ventral margin smoothly concave on outer and inner sides. LV overlaps RV throughout. Inner lamella relatively broad. Marginal pore canals occupy 30 – 100 % of width of inner lamella. Inner lamella of each valve of same individual with at least 90 – 100 marginal pore canals. Sensillae of outer lamella relatively sparse, more frequent in anterior and posterior parts of ventral margin (Fig. 71 A, 71 B), emerging from bordered pores with outgrowth (Fig. 71 E). Outer lamella of each valve of same individual with 90 – 105 pore canals. Microrelief complex, consisting of relatively large, smoothed pits in central part of valves (Fig. 71 C). Rest of valve surface appears smooth (Fig. 71 A), but on close examination it is covered with very small pits (Fig. 71 E – 71 G). Entire carapace on outer side covered with numerous small blind holes (Fig. 71 G). Homogenous microrelief imprints on inner side of both valves (Fig. 71 D). This probably indicates a reduction in microrelief on the valve surface while preserving its imprints on inner side. Site of greatest width (both on ventral and dorsal sides) weakly expressed and located in posterior 1 / 3 of L. Carapace of living specimens is whitish in color and does not lose its color for at least several months when preserved in ethanol. A 1 (Fig. 72 A) eight-segmented. First segment with one seta. Second segment with three setae. Third and fourth segments with one seta each. Fifth and sixth segments with two long setae and one claw each. Seventh segment with two setae and two claws. Eighth segment with two setae of different lengths, one claw and stick-shaped aesthetasc (ya). A 2 (Fig. 72 B, 72 C) five-segmented. Coxal segment with three setae, one of them inserted on this segment, two located between coxal and basal segments. One of them small and pappose. Basal segment with one ventro-distal seta. Exopod with three setae: two short smooth, one long and medially plumose. Endopod three-segmented. First endopodal segment with posteromedial club-shaped aesthetasc (Y), two posterodistal setae of different lengths and rows of pseudochaetae. Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), three t-setae (t 1 – t 3); three z-setae (z 1 two times shorter than z 2 and z 3); three G-claws (G 2 two times shorter than G 1 and G 3) and distal aesthetasc (y 2). Terminal segment with two G-claws (GM and Gm) of almost equal length and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Md (Fig. 53 C). 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: S 1 (long, plumose), S 2 (short, pappose), α (small and short) and proximal seta. Second segment with five posterior setae (β-seta very small), two anterior setae and rows of pseudochaetae. Third segment with four posterodistal setae (γ-seta large, smooth) and three anterior setae. Distal segment with two claws of equal length and three setae (one of them small). Mxl. Protopod without setae. First endite with 14 setae, two at base of endite, 12 at apex. Second endite with nine setae. Third endite with eight setae and two claws. Palp two-segmented; first segment with four setae and rows of pseudochaetae. Distal segment with two claws and seta apically and three setae medially. Branchial plate with 23 setae and long row of pseudochaetae. L 5 (Fig. 73 D). 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 rows of small pseudochaetae. Branchial plate reduced to two setae of different lengths. L 6 (Fig. 73 A) five-segmented. First segment with d 1 - seta. Second and third segments with distal seta (e, f) each and rows of small pseudochaetae. Fourth segment with two distal g-setae and rows of pseudochaetae. Fifth segment with strong long claw (h 2) and two setae (h 1 and h 3) of different lengths. L 7 (Fig. 73 B, 73 C) five-segmented. First segment with anterior d 1 - seta, posterior dp-seta; d 2 seta absent. Second segment with rows of small pseudochaetae. Third segment without pseudochaetae. Fourth segment with posterodistal g-seta and rows of small pseudochaetae. Third and fourth segments incompletely separated (separated on inner side, and partially fused on outer side). Fifth segment with three serrate setae (h 1 – h 3) of different lengths. UR (Fig. 73 H) symmetrical, with smoothly curved main axis. Each ramus with one posterior seta distal to middle of ramus, one short anterodistal seta and two thick distal claws of almost equal length. Male. Carapace (Figs. 69 E – 69 H; 70 G, 70 H; 74 D) laterally elongated-trapezoidal, longer and slightly lower than that of female; L = 780 µm, greatest H = 415 µm. Carapaces of females and males differ very slightly, but testes and ovaries are clearly visible through valves. Inner lamella of each valve with 75 – 80 marginal pore canals. Other morphological features of carapace, A 1, A 2 (protopod, exopod and first endopodal segments), Md, Mxl, L 5 protopod, L 6, L 7, as in female. A 2 (Fig. 72 D – 72 G) six-segmented (four-segmented endopod). Second endopodal segment with one ventromedial seta, dorsal-medial aesthetasc (y 1), three t-setae (t 2 and t 3 modified into sensory setae with oval ends). Third endopodal segment with three z-setae (z 2 modified into long claw), three G-claws (G 2 2.5 times longer than G 1 and G 3) and distal aesthetasc (y 2). Last segment with long Gm-claw, short GM-claw, and two setae, one of them basally fused with stick-shaped aesthetasc (y 3). Prehensile palps of L 5 (Fig. 73 E, 73 F) asymmetrical. Both palps long, straight proximally to site of insertion of two setae, and crescent-curved distally. Right palp significantly thicker than left. Distal tip of both palps with short and thick seta. Hemipenis (Fig. 75 D) large, rectangular, 300 µm long and 125 µm wide; lobes oval. Zenker organ (Fig. 75 H) 245 µm long, with 5 + 2 rings of spines 80 µm in diameter, diameter of central tube 30 µm, vesicle large, 55 µm in diameter. UR (Fig. 73 G) as in female, but claws slightly thinner, and rami straighter. Juvenile stages very similar to adult individuals in carapace morphology (Fig. 70 I). Comparisons. Generally, the shell morphology of the new species resembles Candona limpida Mazepova, 1984 and Candona digitata Mazepova, 1990. Valves of the three species have unique outlines. Sexual dimorphism of the valves of C. perforata sp. nov. is not observed, while the female and male valves of C. limpida and C. digitata are remarkably different. The A 1, A 2, L 5, and UR of C. digitata are extremely peculiar and well distinguished from those of the new species. The UR of C. limpida females and males bear long thin claws (their length is almost half of the ramus length), and the posterior seta is half as long as the claws. Female and male UR of C. perforata sp. nov. have short and thick claws (their length is almost 1 / 3 of the ramus length), and the posterior seta is longer than the claws. The male prehensile palps of C. limpida, distal to the attachment place of two setae, are much longer and thinner than in the new species. The hemipenes show different morphologies; the drawings (Mazepova 1990: p. 110: Fig. 38 O) show that the inner ducts of C. limpida hemipenes are much more proximal than in C. perforata sp. nov. Geographic distribution. Endemic to Lake Baikal, found in the coastal zone of Dagarskaya Bay (depth 12 m). Lives on sand with detritus.	en	Alekseeva, Tatyana M., Krivorotkin, Roman S., Timoshkin, Oleg A. (2025): New and poorly known species of family Candonidae (Crustacea, Ostracoda, Podocopida) from Lake Baikal. Zootaxa 5734 (1): 1-91, DOI: 10.11646/zootaxa.5734.1.1, URL: https://doi.org/10.11646/zootaxa.5734.1.1
