Coronatella (Ephemeralona) elegans (Kurz, 1875)

Garibian, Petr G., Aksenova, Mariia D. & Sinev, Artem Yu., 2021, First record of the water flea Coronatella (Ephemeralona) elegans (Kurz, 1875) (Cladocera: Anomopoda) in Russia, Arthropoda Selecta 30 (1), pp. 34-38 : 37

Coronatella (Ephemeralona) elegans (Kurz, 1875)

Figs 1–2 .

MATERIAL EXAMINED HERE: 10 parthenogenetic females, ephippial female and adult male from a roadside ditch near Malye Derbety, Republic of Kalmykia (47.97072°N, 44.70483°E), collected on 3.05.2019 by P.G. Garibian, sample AAK-M-5433; over 200 parthenogenetic females, over 20 ephippial females, over 20 males from a temporary pool at Taman’ Penninsula west of Taman’ town, Temryuk District , Krasnodar Territory, (45.22278°N, E 36.68472°E) collected on 6.06.2009 by Y. R. Galimov, AAK M-0972; over 20 parthenogenetic females, 3 ephippial females from a pond at Taman Penninsula west of Taman’ town, Temryuk District , Krasnodar Territory, (45.2175°N, E 36.66167°E) collected in 6.06. 2009 by Y. R. Galimov, AAK M-0973. All samples kept in collection of Dr A.A. Kotov, A.N. Severtsov Institute of Ecology and Evolution , Moscow, Russia.

PARTHENOGENETIC FEMALE. Length of adults 0.42–0.52 mm, height 0.29–0.35 mm. Body ovoid in lateral view, compressed laterally, without a medial keel and/or lateral outgrowth, maximum height at middle of body ( Fig. 1A ). Dorsal margin strongly and regularly convex, posterior margin slightly convex, postero-dorsal and postero-vental angles visibly rounded. Ventral margin almost straight, anterior-ventral angle rounded. Valve sculpture with thick, densely located longitudinal and sometimes anastomizing doubled lines, different modes of valve re-enforcing are characteristic for benthic cladocerans [Kotov, 2006]. Ventral margin ( Fig. 1C–E ) with numerous setae different in size, shortest one in the middle, postero-ventral angle with numerous setules at inner side of valve margin ( Fig. 1E ). Head small, with a short rostrum, eye and ocellus welldeveloped, distance between eye and ocellus comparable to distance between ocellus and tip of rostrum. Three connected main head pores ( Fig. 1B ), PP about 1.7 IP, small lateral head pores located at about IP distance from midline, at the level of middle major head pore. Labrum ( Fig. 1F ) with a relatively large labral keel with a round apex. Postabdomen ( Fig. 1J, K ) relatively short and broad, distal part almost straight, dorsal and ventral margin almost parallel in anal portion, ventral portion slightly convex. Preanal margin almost straight, anal margin concave, postanal margin convex. Preanal angle well-defined, postanal angle ill-defined. Postanal margin bearing six or more clusters of simple marginal denticles, decreasing in size proximally. Anal margin with several groups of setules. Lateral side of postabdomen with about 9 fascicles of setules. Antenna I ( Fig. 1G ) elongated, relatively large, its tip almost reaching tip of rostrum, bearing nine aesthetascs and sensory slender setae. Antenna II ( Fig. 1H, I ) short, with a robust basipodite and stout branches. Antennal formula: setae 0-0-3/1-1-3, spines 1-0-1/0-0-1. Limb I ( Fig. 2A ) of moderate size. ODL with a single long minute setulated seta, accessory seta long. IDL with 3 setae, seta 1 reduced, seta 2 and 3 long setulated with thin spinules. Expodite of limb III ( Fig. 2B ) with 6 setae of different size. Seta 3 the longest one, seta 4 slightly shorter than seta 5 armed with two types of setules in distal portion.

EPHIPPIAL FEMALE. Body slightly higher than parthenogenetic female ( Fig. 2C ). Ephippium from yellow-brown to dark-brown, covered by prominent longitudinal lines.

MALE. Body oval ( Fig. 2D ), more elongated than that of parthenogenetic female. labral keel ( Fig. 2E ) slightly shorter than that of parthenogenetic female. Postabdomen ( Fig. 2G ) short, slightly narrowing distally in postanal portion. Dorsal distal angle broadly rounded, postanal angle ill-defined, preanal angle well defined. Spermoduct opens ventrally at distal end of postabdomen. In place of marginal denticles are located clusters of short setulae, lateral fascicles of setules same as in parthenogenetic female. Postabdominal claw shorter than female, its tip blunt, basal spine long, with cluster of long setulae. Antenna I ( Fig. 2F ) shorter than in female, with 10 terminal and 2 lateral aesthetascs, male seta arising at 3/4 length from the distal part, about 1/4 of antenna length. Limb I ( Fig. 2H ) IDL with U-shaped copulatory hook. Copulatory brush seta present. IDL with two seta, seta 2 and 3 slightly shorter than in female, seta 1 is absent, male seta thick and curved.

Discussion

Morphology of the studied populations fully agrees with the recent redescription of Coronatella (Ephemeralona) elegans [Sinev, 2020]. It clearly differs from two other species of the subgenus found in Russia, south Siberian C. (E.) floessneri ( Sinev, Alonso et Sheveleva, 2009) and C. (E.) irinae ( Sinev, Alonso et Sheveleva, 2009) in long seta 4 on exopodite III and in male postabdomen with broad postanal portion (see Sinev et al., 2009). C. (E.) elegans inhabits temporary water bodies in Central Europe of Central Europe and Mediterranean [ Smirnov, 1971; Bromley, 1993; Alonso, 1996, Flössner, 2000; Ghaouaci et al., 2018; Sinev, 2020], its easternmost record from Europe is from Slovenia [ Hudec, 2010], at about 1400 km from Taman’ peninsula and 2000 km from Kalmykia. Our data suggest that the species can be present in the vast arid area along the north coast of the Black Sea – South Ukraine and the southern part of European Russia. Sars [1903] reported C. (E.) cf. elegans (as Alona elegans ) from water bodies in Akmolinsk (now Nur-Sultan), Kazakhstan, but his drawings and description are not detailed enough to confirm population identity with C. (E.) elegans s.str. [Sinev, 2020]. Species inhabiting temporary waters frequently remain undiscovered, as the main attention of hydrobiologists is focused on economically important rivers and permanent lakes.

Our data demonstrate the importance of sampling in temporary waterbodies for full evaluation of local Cladocera fauna, especially in arid areas. Cladocera of the South European part of Russia, especially in steppe regions, are far from fully studied.

Figures

Fig. 1. Coronatella (Ephemeralona) elegans (Kurz, 1875) from roadside ditch near Malye Derbety, Republic of Kalmykia, European Russia, adult parthenogenetic female: A — lateral view, B — head pores, C, D, E — valves armature, F — labrum, G — antenna I, H, I — antenna II, J, K — postabdomen. Scale 0.1 mm (A, C, H), 0.05 mm (B, D–G, I–K). Рис. 1. Coronatella (Ephemeralona) elegans (Kurz, 1875) иЗ канавы в районе пос. Малые Дербеты, Республики КалмыкиЯ, европейскаЯ часть РФ, вЗрослаЯ партеногенетическаЯ самка: A — вид сбоку, B — головные поры, C, D, E — вооружение створок, F — лЯбрум, G — антенна I, H, I — антенна II, J, K — постабдомен. МасШтаб 0,1 мм (A, C, H), 0,05 мм (B, D–G, I–K).

Fig. 2. Coronatella (Ephemeralona) elegans (Kurz, 1875) from from roadside ditch near Malye Derbety, Republic of Kalmykia, European Russia: A, B — adult parthenogenetic female, C — ephippial female, D–H — adult male. A — limb I, B — limb III exopodite, C — lateral view, D — lateral view, E — labrum, F — antenna I, G — postabdomen, H — limb I. Scale 0.1 mm (C, D), 0.05 mm (A, B, E–H). Рис. 2. Coronatella (Ephemeralona) elegans (Kurz, 1875) иЗ канавы в районе пос. Малые Дербеты, Республики КалмыкиЯ, европейскаЯ часть РФ: A, B — вЗрослаЯ партеногенетическаЯ самка, C — ЭфиппиальнаЯ самка, D–H — вЗрослый самец. A — торакопод I, B — ЭкЗоподит торакопода III, C — вид сбоку, D — вид сбоку, E — лЯбрум, F — антенна I, G — постабдомен, H — торакопод I. МасШтаб 0,1 мм (C, D), 0,05 мм (A, B, E–H).