Daphnia (Daphnia) sinevi Kotov, Ishida & Taylor 2006

Daphnia (Daphnia) sinevi Kotov, Ishida & Taylor, 2006

(Figs 1–3)

Daphnia (Daphnia) sinevi Kotov, Ishida & Taylor, 2006: p. 1070 –1077, figs 3–5; Kotov et al. 2011a: p. 405.

Daphnia sinevi group clade H in Kotov & Taylor 2019: figs 1–2.

Type locality. “ A pond about 10 m in diameter in Avangard, Nakhodka Area (42º 48’ N, 132º 53’ E), Primorski Krai, Russia ” (Kotov et al. 2006).

Type material. Holotype. A parthenogenetic female, MGU Ml 46.

Allotype. Adult male, MGU Ml 47.

Paratypes. 20 parthenogenetic females, MGU Ml 48; 3 ephippial females, MGU Ml 49, 12 juvenile and adult males, MGU Ml 50; 12 females, AAK 2005-195.

Material examined here. Primorski Territory. Many males, ephippial and parthenogenetic females from: a pond 10 m in diameter in Avangard, Nakhodka Area, coll. on 25.09.2004 by A.Y. Sinev (type locality), AAK M-0061; puddle 1 and 2 near Komarovka River, Ussurisky Nature Reserve, coll. on 09.092009 by P.A. Sorokin (43.64833° N, 132.3951° E), AAK M-1301-1302; a puddle near the shore of Khanka Lake near the TINRO station, coll. on 12.09.2009 by N.M. Korovchinsky (44.76017° N, 132.0577° E), AAK M-1278; a puddle near the reservoir of Luchegorskaya power station, coll. on 10.09.2007 by A.A. Kotov & S.A. Ivanov (46.45208° N, 134.2991° E), AAK M-0651; a puddle, Partizanskaya Street 1, village of Fedoseevka, coll. on 10.09.2007 by A.A. Kotov & S.A. Ivanov (46.53117° N, 134.2777° E), AAK M-0652; an oxbow lake, near River of Schegolikha, coll. on 10.09.2007 by A.A. Kotov & S.A. Ivanov (46.54158° N, 134.2648° E), AAK M-0653. Khabarovsk Territory. Many males, ephippial and parthenogenetic females from puddles 1 and 2, Pionerskaya Street, Khabarovsk, coll. on 31.08.2007 by A.A. Kotov & N.M. Korovchinsky (48.39455° N, 135.0905° E), AAK M-0616, AAK M-0617, AAK M-0654; a roadside ditch, road to village of Sinda, 30.08.2007 by A.A. Kotov & N.M. Korovchinsky (48.97978° N, 136.3089° E), AAK M-0615.

Diagnosis. Parthenogenetic female. Body subovoid, maximum height in middle of valves. Dorsal margin of valves slightly elevated above head, shallow depression between head and rest of body. Postero-dorsal angle with a short a caudal spine (Fig. 1 A–C) or lacking it (as in type series, see Kotov et al. 2006). Head with a moderate rostrum; in lateral view, the tip subdivided into two lobes. Posterior margin of head with a strong prominence proximally to antenna I (Fig. 1D, E). Sometimes a low crest developed on head (Fig. 1B), while other populations lacking of a crest, compound eye large, ocellus small and located far from base of antenna I. Spinules present on dorsal and ventral margins only near caudal spine or completely absent when spine reduced (Fig. 1C). Postabdomen elongated, lacking of setules (Fig. 1C). Preanal margin long, slightly concave, with series of minute setules. Postabdominal claw with basal pecten consisting of stiff setules; second pecten of 5–7 teeth increasing in size distally; third pecten consisting of fine setules. Antenna I as a very low stump, with nine aestetascs of different length terminally, their tips reaching tip of rostrum (Figs. 1D, E). Denticles on proximal portion of the distal segment of seta 2 on exopodite III are distributed similarly to following denticles. Exopod setae 1 and 2 on limb V of unequal size.

Ephippial female. Postero-dorsal portion of valves incorporated into ephippium.

Adult male. Body low; dorsal margin of valves straight; postero-dorsal angle distinct, with a short caudal spine (Fig. 2A). Head with a moderately developed rostrum; region of antenna I joint with a special depression (Fig. 2 BD). Anteriormost extremity fully occupied with optic vesicle; a very shallow supra-ocular depression posteriorly to it, or completely absent. Compound eye large, ocellus small. Valves with anterior-ventral angle distinctly prominent ventrally; all ventral margins with long, numerous setae located submarginally on inner face of valve (Fig. 2 E–F). Posterior portion of valve with a row of setulated setae and rows of minute setules between them (Fig. 2 G–I). Spinules present on dorsal and ventral margins only near caudal spine (Fig. 2 J–K).

Abdomen with reduced processes, only small mound present on each first and second segment from basal end (Fig. 2 L–M). Postabdomen shape and armature in general same as in female, but preanal margin shorter. Postanal portion with 8–11 paired large teeth that strongly increasing in size distally. Gonopore opens subdistally, without a genital papilla (Fig. 2N). Outer surface of postabdominal claw with three pectens: basal pecten of stiff setules; second pecten of 5-7 teeth with size slightly increasing distally; third pecten with fine numerous setules (Fig. 2 N–P).

Antenna I long, relatively straight; antennular seta located far from distal end of antenna I body, small, its length approximately as antenna I diameter; aesthetascs of different length (Fig. 3 A–B). Male seta on top of a distal process, long and bisegmented; distal segment setulated, with a hooked tip (Fig. 2 B–D).

Limb I (Fig. 3C) with ODL large, cylindrical, with a small and a very large setae (Fig. 3D) setulated distally with minute setules (Fig. 3E); IDL bearing a bent copulatory hook and two setae of different size, endite 3 with four setae (Fig. 3 C–E). Limb II distalmost endite bearing a modified hook-like setae 1 setulated distally (Fig. 3 F–G).

Juvenile male. Body subovoid; head with a very short rostrum (Fig. 3H), sometimes with a neck tooth (see Kotov et al. 2006). Carapace dorsal margin almost straight; caudal spine well-developed, and 1/3–1/2 of ventral margin covered by spinules (Fig. 3H). Postabdomen as in adult male (Fig. 3J). Limb I ODL (Fig. 3K) long seta shorter than in adult males; copulatory hook shorter and almost straight (Fig. 3 K–L).

Size. Parthenogenetic female 0.69–1.73 mm, male 1.01–1.22 mm.