Alonopsis aureolata Doolittle, 1912

Sinev, Artem Y. & Atroschenko, Margarita M., 2011, Revision of the genus Alonopsis Sars, 1862 and its position within Aloninae (Cladocera: Anomopoda: Chydoridae), Zootaxa 2800, pp. 1-17: 13-14

publication ID 10.5281/zenodo.203597

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Alonopsis aureolata Doolittle, 1912


Alonopsis aureolata Doolittle, 1912 

Doolittle, 1912: 561–565, Pls. 42–43; Kubersky, 1977: 656–663, figs 3–20 ( americana  ).

Type locality. Lake Sunapee, Sullivan County, New Hampshire, USA.

Holotype: immature female on a slide, U. S. National Museum (cat. 4 # 44366), from Lake Sunapee, Sullivan County, New Hampshire, USA collected 22.04. 1910.

Material. 37 parthenogenetic females from Sebago Lake, Maine, USA, 0 9.07. 1966, coll. D. G. Frey, National Museum of Natural History (Washington DC, USA), Frey’s collection sample 1912.

Description. Parthenogenetic female. Body ( Fig. 6View FIGURE 6 A, C, E –F) height-length ratio about 0.59–0.63. Valves ( Fig. 6View FIGURE 6 G –H) and head as for genus. Head shield ( Fig. 7View FIGURE 7 A) with very short, broadly rounded rostrum. Head pores as for genus ( Fig. 7View FIGURE 7 B), IP/PP ratio about 1.5–2 in adult. Labrum as for genus ( Fig. 7View FIGURE 7 C –D). Thorax, abdomen and postabdomen ( Fig. 6View FIGURE 6 B, D, I –J) as for genus, same as in the previous species.

Antennule ( Fig. 7View FIGURE 7 F), antenna ( Fig. 7View FIGURE 7 D) and limb I ( Fig 7View FIGURE 7 G –H) same as in the previous species. Limb II ( Fig. 7View FIGURE 7 I) with scrapers 7 and 8 of similar size and shape, armed with 12–15 long, thick denticles. Limbs III ( Fig. 7View FIGURE 7 J –L) and limb IV ( Fig. 8View FIGURE 8 A –C) same as in the previous species. Limb V ( Fig. 8View FIGURE 8 D) as for genus, incursion between exopodite lobes as obtuse angle. Limb VI ( Fig. 8View FIGURE 8 E) with clusters of marginal setules in studied specimens of different proportions compared to the previous species.

Male. According to description of Kubersky (1977), body shape is similar to that of the previous species. Postabdomen ( Fig. 8View FIGURE 8 F) narrowing distally, but curved, with irregularly curved ventral margin and concave postanal margin, postanal angle defined, obtuse. Position of sperm ducts, armament of postabdomen, postabdominal claws similar to the previous species. Descriptions and drawings of antennule and limb I in description of Kubersky (1977) are somewhat vague. These structures appear to be similar to these of the previous species, but some differences possibly remain overlooked.

Size. In studied material, length of female of juvenile instar I— 0.41–0.46 mm; juvenile instar II— 0.50–0.57 mm; adult female— 0.62–0.89 mm.