Eurycercus glacialis Lilljeborg, 1887

Bekker, Eugeniya I. & Kotov, Alexey A., 2016, A revision of the subgenus Eurycercus (Teretifrons) Frey, 1975 (Crustacea: Cladocera) in the Holarctic with description of a new species from Russian Arctic, Zootaxa 4147 (4), pp. 351-376 : 353-358

publication ID	https://doi.org/ 10.11646/zootaxa.4147.4.1
publication LSID	lsid:zoobank.org:pub:550E60AC-54F6-4FB4-8A79-058A0996B598
DOI	https://doi.org/10.5281/zenodo.5631049
persistent identifier	https://treatment.plazi.org/id/03CD879F-9C32-FF85-56A3-287BE3CEFF1A
treatment provided by	Plazi
scientific name	Eurycercus glacialis Lilljeborg, 1887
status

Treatment

Eurycercus glacialis Lilljeborg, 1887 View in CoL

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Eurycercus glacialis Lilljeborg 1887 View in CoL , P. 154–155; Lilljeborg 1901, P. 393–398, Pl. 60: Fig. 11 View FIGURE 11 , Pl. 61: Figs 1–13 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 ; Wibaut- Isebree Moens 1913, P. 227–233, Figs 2 View FIGURE 2 , 4 View FIGURE 4 ; Redeke 1930, P. 87–88; Beijerinck 1931, P. 243–246, Figs 3 View FIGURE 3 , 4 View FIGURE 4 ; Luyten 1933, P. 71–72, Figs 12–13 View FIGURE 12 View FIGURE 13 ; Wagler 1937, P. 50, Figs 186b, d, 187 (after Lilljeborg, 1901); Poulsen 1939, P. 22, Fig. 8 View FIGURE 8 a; Poulsen 1940, P. 29–33, Fig. 11 View FIGURE 11 ; Redeke 1948, P. 405–406, Fig. 397; Kaiser 1959. P. 17–33, Figs 5 View FIGURE 5 A–B, 6A, 7B, 8–9; Frey 1958, Pl. 36: Figs 20, 24; Herbst 1962, P. 80: Fig. 54a–c; Manujlova 1964, P. 210, Fig. 98: 1–4; Frey 1971, P. 258–260 (in partim); Flössner 1972, P. 272–274, Fig. 129; Duigan & Frey 1987, P. 241–247, Figs C–D; Hann 1990, P. 2146, Figs 1–14 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 ; Duigan 1991, Figs 1–2 View FIGURE 1 View FIGURE 2 ; Minakawa & Tanaka 2000, P. 891–892; Røen 1995, P. 195–197, Fig. 90B, 91A–C (after Lilljeborg 1901 & Flössner 1972); Flössner 2000, P. 227–230, Fig. 86a–l; Minakawa et al. 2006, P. 111–114, Figs 1–10 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ; Bekker 2012, P. 119–125, Figs 38–40; Novichkova et al. 2014, P. 1761; Novichkova & Chertoprud 2016, P. 1361.

Eurycercus lamellatus (Mueller) in Wesenberg-Lund 1894 View in CoL , P. 123–125, Pl. 4: Fig. 20.

Eurycercus glacialis View in CoL ? Lilljeborg in Inoue 1968, P. 152, Fig. 4 View FIGURE 4 .

not Eurycercus glacialis in Cushman 1908 View in CoL , P. 710–711, Pl. 61: Fig. 5 View FIGURE 5 , Pl. 62: Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 .

Type locality. Unknown waterbody in Bering Island, Commandor Islands , Russia.

Type material. Lectotype and paralectotype. UUZM #547 a–m, from "Beringön 1882-1883, Fr. Steineger" ( Hann 1990).

Material examined here. Greenland ( Denmark): 10 parthenogenetic ♀♀ from unnamed shallow pond (<1m) (N67.148°, W50.08°) near Kangerlussuaq and glacial ice sheet margin, coll. in 0 8.2009 by Y. Axford, AAK 2010- 0 0 7. 4 parthenogenetic ♀♀ from unnamed lake with narrow rocky shelf (N67.129°, W50.17°) near Kangerlussuaq and glacial ice sheet margin, coll. in 0 8.2009 by Y. Axford, AAK 2010-008. 10 parthenogenetic ♀♀ from Tigssaluk (appr. N61.36°, W48.58°), coll. in 1880 by N.O. Holst, UUZM 38866 View Materials GoogleMaps .

Iceland: 4 parthenogenetic ♀♀ from a lake (N66.351°, W14.97°) on Langanes Peninsula (middle), coll. in 12.06.2012 by E. Chertoprud & A.A. Novichkova, AAK M-2559. 1 parthenogenetic ♀ from a lake near Drainage Divide, coll. in 18.08.1972 by D.G. Frey. 7 parthenogenetic ♀♀ from Pond 31 near Godafoss, Skjálfandafljót, Mývatn GoogleMaps , Northeast Region, coll. in 17.08.1972 by D.G. Frey, DGF 3224-3225. 24 parthenogenetic ♀♀ from Pond 34, Seydisfjördur. coll. in 18.08.1972 by D.G. Frey, DGF 3229. 22 parthenogenetic ♀♀ from Pond 35, Seydisfjördur, coll. in 18.08.1972 by D.G. Frey, DGF 3231-3233. 2 parthenogenetic ♀♀ from Pond 37, Seydisfjördur, coll. in 18.08.1972 by D.G. Frey, DGF 3234. 1 parthenogenetic ♀ from Pond 39, Lagarfljót, coll. in 19.08.1972 by D.G. Frey, DGF 3236. 2 parthenogenetic ♀♀ from Pond 39, Lagarfljót, coll. in 19.08.1972 by D.G. Frey, DGF 3237. 120 parthenogenetic ♀♀ from Pond 45, Westside of Lake at Egilsstaðir, coll. in 19.08.1972 by D.G. Frey, DGF 3243. 50 parthenogenetic ♀♀ from Pond 47, Egilsstaðir, coll. in 19.08.1972 by D.G. Frey, DGF 3246. 50 parthenogenetic ♀♀ from Pond 47, Egilsstaðir, coll. in 19.07.1972 by D.G. Frey, AAK 2010-069. 31 parthenogenetic ♀♀ from Pond 48, Egilsstaðir, coll. in 19.07.1972 by D.G. Frey, DGF 3247. 38 parthenogenetic ♀♀ from Pond 49, Egilsstaðir, coll. in 19.07.1972 by D.G. Frey, DGF 3248. 26 parthenogenetic ♀♀ Pond 52, 2.4 km from Egilsstaðir, coll. 20.07.1972 by D.G. Frey, DGF 3251. 14 parthenogenetic ♀♀ from Pond 56 near Eidar, coll. in 20.07.1972 by D.G. Frey, DGF 3257. 40 parthenogenetic ♀♀ from Pond 57 , Eidar, coll. in 20.07.1972 by D.G. Frey, DGF 3258.

Netherlands: 1 parthenogenetic ♀ from a small eutrophic water body (appr. N53.45°, E5.7°) on Ameland Island, Westfrisian Islands, coll. in 12.08.1980 by W. Hollwedel, AAK 1999-109. 10 parthenogenetic ♀♀ from Badhujsplak Dune Lake (appr. N53.4°, E5.3°), Terschelling Island, Westfrisian Islands, coll. in 24.08.1965 by P.

Leentvaar, NNS 1999 - 006. 10 parthenogenetic ♀♀ from unknown dune lake, coll. in 24.08.1965 by U. Hunenplak, NNS MGU 0 328.

Russia (Asian): 1 parthenogenetic ♀ from Lake Ladyginskoe (appr. N55.26°, E165.96°), Bering Island, Kamchatka Area, coll. in 2002 by Zh. Antipushina, AAK 2008-098. 15 parthenogenetic ♀♀ from a water body (appr. N55.3°, E165.9°) near Lake Ladyginskoe, Bering Island, Kamchatka Area, coll. in 13.08.2011 by A.A. Novichkova, AAK M-2269. About 50 parthenogenetic ♀♀ from Lake Tsentral'noje (N54.496°, E159.98°), Caldera Uzon, Kamchatka Area, coll. in 29.08.1995 by Y.R. Galimov, NMK 2712 View Materials . 8 parthenogenetic ♀♀ from a lake (appr. N53.01°, E143.09°) about 15 krn northeast of Neftegorsk and 3 km northwest of Point Matny in Piltun Bay, Northern Sakhalin, Sakhalin Area, coll. in 14.08.2003 by V.V. Bogatov & N. Minakawa, AAK M-0513. 20 head shields from a shallow lake (appr. N62.06°, E156.32°), 20 km N of Merenga village, Magadan Area, NNS 1999 - 0 0 7. 5 parthenogenetic ♀♀ from a lake in tundra (appr. N59.6°, E150.9°), vicinity of Magadan, Magadan Area GoogleMaps . coll. in 13.08.1975 by E.A. Streletskaya, NNS 1999 -009. 1 parthenogenetic ♀ from a water body in the Anadyr River basin, №348, б-135-72, Chukot Autonomous Area , coll by E.A. Streletskaya, NNS 1999 -012.

U.S.A. (Alaska): 10 parthenogenetic ♀♀ from a shallow pond (N57.829°, W152.41°) in sitka spruce temperate rainforest, Kodiak Island, coll. in 12.08.2005 by D.J. Taylor, AAK M-1115. 5 parthenogenetic ♀♀ from Moor at Talsome (?), ca GoogleMaps . 150 km NE of Ancourage, coll. in 28.08.1978 by R. Harmsworth, DGF 6945. 25 parthenogenetic ♀♀ from a pond (N64.881°, W163.7°) near Council, Sewart Peninsula, coll. in 29.07.2011 by D.J. Taylor, A.A. Kotov, M. Ballinger & A. Medeiros, DJT20_2011_Council 0 6. 7 parthenogenetic ♀♀ from a pond (N64.874°, W163.7°) near Council, Sewart Peninsula, coll. in 29.07.2011 by D.J. Taylor, A.A. Kotov, M. Ballinger & A. Medeiros, DJT20_2011_Council 0 9. 35 parthenogenetic ♀♀ from a pond (N64.878°, W163.7°) near Council, Sewart Peninsula, coll. 0 208.2011 by D.J. Taylor, A.A. Kotov, M. Ballinger & A. Medeiros, DJT20_2011_Council 25. 19 parthenogenetic ♀♀ from a pond (N64.926°, W164.9°) near Taylor, Sewart Peninsula, coll in 30.07.2011 by D.J. Taylor, A.A. Kotov, M. Ballinger & A. Medeiros, DJT3 2011_Taylor 100.

Diagnosis. Parthenogenetic female. In lateral view body sub-ovoid ( Fig. 1 View FIGURE 1 A), maximum height of the body in its middle portion (BH/BL= 0.63–0.74; VL/BL=0.81–0.93). In anterior or dorsal view, body is not compressed laterally, median dorsal keel absent ( Fig. 1 View FIGURE 1 B–C). Rostrum relatively long ( Fig. 1 View FIGURE 1 D). Ocellus small. Head shield wide ( Fig. 1 View FIGURE 1 E). Dorsal head pores located in midline of head shield in its posterior portion; no projections in this area, ring of major head pore not elevated above head shield. Lateral head pores elongated along longitudinal body axis ( Fig. 1 View FIGURE 1 F). Labrum with a large median keel terminated as an angled apex projected beyond tip of antenna I ( Fig. 1 View FIGURE 1 D, G). Postabdomen as a large (PL/BL= 0.42–0.52), relatively broad ( PH /PL= 0.51–0.61) plate with subparallel ventral and dorsal margin ( Fig. 2 View FIGURE 2 A) and deep anal embayment ( Fig. 2 View FIGURE 2 A–B). Preanal teeth pointed (NT= 99–110 in adults), dark, strongly chitinized or without pigmentation ( Fig. 2 View FIGURE 2 C), a gap between proximalmost tooth and bases of postabdominal setae ( Fig. 2 View FIGURE 2 D). Teeth in distal part of postanal margin large, long, predominantly doubled; teeth in distal part of anal – basal part of postanal margin short, almost all of them single ( Fig. 2 View FIGURE 2 B). Postabdominal claw relatively robust (CL/PL=0.21–0.29) with two basal spines (DS/CL=0.27–0.37; BS/CL=0.11– 0.16; BS/DS=0.31–0.48). Antenna I elongated (AL/BL=0.10–0.14; AL/DA=4.3–5.5); antennular sensory seta ( Fig. 2 View FIGURE 2 E, ass) arising in antenna I distal part ( Fig. 2 View FIGURE 2 E); numerous short rows of minute denticles encircling antennular surface. On antenna II, a spine situated on proximal segment of exopod equal in length of that of second segment or slightly longer ( Fig. 2 View FIGURE 2 F). Limb I with IDL ( Fig. 2 View FIGURE 2 G, IDL) with three bisegmented setae, one of them a relatively strong hook-like seta, its diameter at base is equal or slightly more than diameter at base of longest setae of IDL. The smallest of the three setae relatively short, its length in two or more times less than longest setae of IDL. IDL supplied with 10–12 long distal spinules ( Fig. 2 View FIGURE 2 H–I, dis), 11–15 long proximal spinules ( Fig. 2 View FIGURE 2 H, pro), and 10 very short basal spinules ( Fig. 2 View FIGURE 2 H, bas), marginal spinules absent ( Fig. 2 View FIGURE 2 H, position of these spinules in other species marked as mar). Eight setae in filter plate II ( Fig. 3 View FIGURE 3 A, fpl), four setae in distal armature of gnathobase II ( Fig. 3 View FIGURE 3 B, dag); 10 setae in filter plate III ( Fig. 3 View FIGURE 3 C), three setae in distal armature of gnathobase III ( Fig. 3 View FIGURE 3 D); 9–10 setae in filter plate IV ( Fig. 3 View FIGURE 3 E), four setae in distal armature of gnathobase IV ( Fig. 3 View FIGURE 3 F), 8–9 setae in filter plate V ( Fig. 3 View FIGURE 3 G), two hooks on gnathobase V ( Fig. 3 View FIGURE 3 H); limb VI as a oval plate ( Fig. 3 View FIGURE 3 I). Exopodite IV ( Fig. 3 View FIGURE 3 E, ext) with 8 setae, exopodite V with 8 setae. Intestine with a double loop ( Fig. 1 View FIGURE 1 A, ilp), posterior intestinal caecum absent ( Fig. 1 View FIGURE 1 A, pic).

Ephippium. Entire shell serves as ephippium, which is from almost transparent to strongly pigmented depending on environmental conditions ( Kaiser 1959).

Adult male (short diagnosis based on Flössner (1972, 2000)). In lateral view body more elongated as compared with female. Rostrum short. Labral keel small (shorter than antenna I), with a well-developed apex. Postabdomen as in female. Antenna I more thick as compared with that in female, with relatively short antennular sensory setae, located at a distance of 1/3 antenna length from its distal end, and a small male setae located almost medially. Terminal aesthetascs relatively long; additional aesthetascs on posterior surface on antenna I body. Limb I supplied by a strong clasping hook located between IDL and ODL.

Size. Adult parthenogenetic females 3.32–4.32 mm (in our material); adult parthenogenetic females 4.2–6.1 mm ( Hann, 1990); male 1–2 mm ( Flössner, 1972).

Differential diagnosis. Among the species of Eurycercus (Teretifrons) , E. glacialis is unique having no projections in the head pore area and a ring of major head pore not elevated above headshield. In contrast to E. chernovi sp.nov., it has 10 setae in exopodite IV and 8 setae in exopodite V.

Distribution. The species is apparently present in Greenland, Iceland, British Islands ( Duigan & Frey 1987; Duigan 1991), northern islands of Germany and Netherlands, northern Belgium ( Flössner 1972, 2000; De Meester & Bosmans 1993) in Europe; Sakhalin Island, Kurile Islands, Magadan Area, continental Kamchatka Peninsula, Bering Island, Chukotka Peninsula, continental Alaska, Kodiak Island (and, most probably, Aleutian Islands) in Pacific region. In contrast, records from European-Asian Arctic coast (i.e. Scandinavia, Kola Peninsula, Siberia, Vaigatch Island, Novaya Zemlya, and other localities, see Flössner 1972) must be checked, as well as all records from Arctic Canada and U.S.A. (see review of Frey 1971). Such populations could belong to another species (i.e.

described below or undescribed ones). Population determined as E. glacialis from Hokkaido ( Inoue, 1968) could belong to another species. Frey (1971) concluded that this is in reality E. lamellatus , but most probably the latter is absent in Japan ( Bekker et al. 2012). At the same time, Japanese populations could really belong to E. glacialis , because it is present in North Kurile Islands and Sakhalin ( Minakawa & Tanaka 2000; Minakawa et al. 2006), the next-door territories to Hokkaido. See information on ecological preferences of this species in Flössner (1972, 2000).

Comments. At this moment, we can conclude that E. glacialis is an adequately described taxon, see history of its studies in Hann (1990).