биота российских вод японского моря - Materials of Alexey Shipunov

oped, small, armed with 1–2 setae. Endopods relatively weakly armed. First segmentof limb 1 bears 5 small setae, second, 4: two long apical ones and two short ones.Cauda in shape of two thin, long, tapering appendages, not pointed at ends, with rowsof small setules.Podon leuckarti (Sars, 1862)(Pl. V, figs. 1–11)Sars, 1862: 293 (Pleopis leuckarti); Lilljeborg, 1900: 636–639, tabl. 85, fig. 12, tabl. 86,figs. 1–3; Rammner, 1930: 4, figs. 7–8; Manuilova, 1964: 305, fig. 174; Yamazi, 1966: 191, pl.88, fig. 1; Mordukhai-Boltovskoi, 1969: 22, pl. 3, fig. 1; Flössner, 1972: 392, abb. 184; Negrea,1983: 344–345, fig. 142; Mordukhai-Boltovskoi & Rivier, 1987: 115–116, fig. 64; Rivier,1998: 127–128, figs. 66–74 (Podon leuckarti).Description. Parthenogenetic female. Depression between head and shellclearly expressed. Head relatively large; nuchal organ situated nearer to depression.Shell semispherical; if embryos numerous, shell inflated, globular. Swimming antennaewell developed, segments have normal size. Each branch with 6 setae, attachedidentically on outer and inner branches. Thoracic limbs relatively weakly armed. Eachexopod of limbs 1–3 with 1 seta; exopod of limb 4 with 2 setae. Setae of exopodsthick, straight, and covered with spinules. Setal formula 1.1.1.2. First segment of endopodof limb 1 with 4 long curved setae; each endopod of limbs 2–4 with 4 apicalsetae, 2 of them thick and relatively short. Maxillary processes on limbs 2 and 3 robust,with sensory setae and 2–3 large spines. Mandible bears 1 large tooth with 2 lateraldenticles and strongly ramified process, placed perpendicular to main plane ofmandible. Cauda in shape of 2 long thickening outgrowths with rows of small denticlesand setae. Length up to 0.9 mm, height up to 0.8 mm.Gamogenetic female. Shell globular if brood pouch filled with eggs. Egg hassomewhat irregular shape. During membrane forming hypodermic cells clearly visible.Length of body up to 0.75 mm, height up to 0.8 mm. Diameter of resting egg 210–230 µm (Onbe, 1985).Male. Shell smaller than head. Eye larger than in female. Penes small, testes almostnot protruding into shell cavity. Apical segment of limb 1 enlarged, providedwith well-developed hook. Length up to 0.9 mm, height up to 0.8 mm.Distribution. P. leuckarti is one of the most widely dispersed marine species ofthe Podonidae. It is distributed from the coasts of Greenland to the southern tip ofAmerica, from the Spitsbergen and Wrangel Islands to the Mediterranean and SouthChina seas. In the Russian waters of the Far East it occurs in the coastal zone of thenorthern tip of Chukchi Peninsula up to the Gulf of Anadyr, and penetrates in thewarmest belt along the Koryak coast to Olyutorsky Bay and to the south along thecoast of Kamchatka and the Commander Islands (Vinogradov, 1956). It is distributedin the western part of the Bering Sea (Geinrich, 1961) and the northern part of the Seaof Japan (Kun, 1975); it is common in Peter the Great Bay (Kos, 1976, 1977; Brodsky,1981; Mikulich & Biryulina, 1977). However, it is the least abundant species of thepodonids in the Inland Sea of Japan (Onbe, 1985).Biology and ecology. P. leuckarti is a temperate-cold water species. It appears inthe northern part of its geographical range when water is warmest (the end of summerto autumn), and the farther south along the range the earlier it appears. It occurs in the20