биота российских вод японского моря - Materials of Alexey Shipunov

2 (1). Exopod of limb 3 with one seta. Apex of shell pointed, but without peak ....................................................................................................... 2. E. nordmanni (p. 23)Evadne spinifera P.E. Müller, 1867(Pl. VI, figs. 1–8)Müller, 1867: 225, tabl. 6, figs. 11–12; Claus, 1877, tabl. 6, fig. 21; Lilljeborg, 1900:647–649, tabl. 86, fig. 18; tabl, 87, figs. 1–3; Rammner, 1930: 5, figs. 11, 12; Dolgopolskaya,1958: 51–56, figs. 18–21; Manuilova, 1964: 308, fig. 177; Yamazi, 1966: 192, pl. 88, fig. 4;Flössner, 1972: 400–401, abb. 188; Negrea, 1983: 353, fig. 146; Mordukhai-Boltovskoi &Rivier, 1987: 122, fig. 71; Rivier, 1998: 135, figs. 93–100 (Evadne spinifera).Description. Parthenogenetic female. Body ovoid; no nuchal depression;head fused with shell, produced into pointed peak. Swimming antennae weakly developed;segments almost square. Apical segments on both branches more than twiceshorter and thinner than preceding segments; each branch with 6 long, soft, plumosesetae. Exopods of limbs 1–3 with 2 setae; setal formula 2.2.2.1. Mandible with onelarge tooth and 2 horn-shaped processes. Maxillary processes well developed on limbs2 and 3. Length 0.6–0.8 mm, height 1.3–1.4 mm.Male somewhat smaller than female, with large eye, characteristic for podonids,with narrower than in female shell having long pointed peak. Penes not protrudingpast limb 4; testes clearly visible in empty shell cavity. Apical segment of limb 1 withlarge, well-developed hook. Height 1.05–1.3 mm.Distribution. E. spinifera is distributed in all the oceans, excluding polar seas,also in inland seas like the Baltic, the Mediterranean, and the Black. It rarer occurs inequatorial waters compared to temperate waters. E. spinifera does not penetrate theOkhotsk and Bering seas and is not common for the Sea of Japan, where it is the leastabundant form among all the podonids of the Far East seas. Numerous works of Japanesescientists do not register this species for the Inland Sea of Japan.Kos (1976, 1977) and Brodsky (1981), who made detailed research of the zooplanktonof Possjet Bay, do not mention E. spinifera for this region, but it was found in1989–1990 in the south-western part of Peter the Great Bay (Shkoldina & Pogodin,1999, Shkoldina et al., 2004). The species occurs south of the Kuril Islands (40°N),where the warm Kuroshio Current flows (Brodsky, 1955). It is one of the subtropicalspecies of Peter the Great Bay, the subtropical and tropical groups of species beingtwo most important zoogeographical groups of the bay. E. spinifera does not occur inthe neritic zones of the middle and northern coastal waters of Primorye (Kos, 1960).The occurrence of warm-water species of the podonids, including E. spinifera,depends on the effect of warm waters moved by the considerably meandering KuroshioCurrent. When the current veers from the coast, warm-water species disappearfrom Possjet and Peter the Great bays (Kos, 1969). The Kuroshio can transport E. spiniferaas far as the north-eastern coast of Honshu Island (Onbe et al., 1996).Biology and ecology. E. spinifera is a relatively poorly studied species. In thesouthern part of the Sea of Japan (Toyama Bay), where investigations were conductedfrom February 1990 to January 1991, maximum density of E. spinifera was recordedfor July. In September these cladocerans were distributed vertically to a depth of 30 mat night and in the daytime migrated to the surface (Onbe & Ikeda, 1995).22