Eudiaptomus transylvanicus and E. vulgaris (Copepoda: Calanoida: Diaptomidae): comparative morphology, distribution and ecology Author Podshivalina, V. N. Author Sheveleva, N. G. Author Semenova, A. S. Author Mirabdullayev, I. M. text Zoosystematica Rossica 2022 2022-04-11 31 1 42 54 http://dx.doi.org/10.31610/zsr/2022.31.1.42 journal article 57382 10.31610/zsr/2022.31.1.42 581c8112-22c8-496e-af74-e7b5f111636c 2410-0226 10124251 urn:lsid:zoobank.org:pub:041CC6C4-A1DC-42A8-8FEB-7F6F183CA0F3 Eudiaptomus transylvanicus ( Daday, 1891 ) ( Figs 1 , 2 ) Material examined . Russia , Chuvash Republic , near Atrat Vill. , “kopan’” water body, 54.9991°N 46.6685°E , 3 July 2019 , 9 males , 8 females ; same locality, quarry pond, 54.97798°N 46.72082°E , 26 May 2020 , 2 males , 2 females ; same locality, carr lakelet, 54.97798°N 46.72082°E , 26 May 2020 , 4 males (all E. Osmelkin leg.). Redescription. Female ( Fig. 1a ). Body length 1.60–1.66 mm (n = 8). Last thoracic segment with well-developed asymmetrical wings. Genital compound somite gently dilated in central part, with medium-sized hyaline spines ( Fig. 1b , arrowed). Antennules extending closely to apices of apical caudal setae ( Fig. 1a ). Rostrum with two strong long curved asymmetrical processes ( Fig. 1d ). Edge of mandibular incision with single-vertex teeth: one ventral and six or seven central ( Fig. 1c, 1c′ ). Ventral tooth separated from other teeth by a deep diastema ( Fig. 1c′ ). Rather deep diastema present between outer ventral central tooth and other teeth. Central teeth acute, with wide base ( Fig. 1c′ ). Dorsal teeth double-vertex, acute, with narrow base. Maxilla and maxilliped with long plumose setae increasing filtration; these setae situated on sympodite compounds (precoxopodite, coxopodite), basipodite and endopodite. In leg 2, endopod segment 2 with Schmeilsche lobus ( Fig. 1e , arrowed). In leg 5, coxa with triangular lateral projection, with wide base, nearly as large as basipod ( Fig. 1f ); exopod segment 1 rectangular; exopod segment 2 with spine (bearing row of spinules) at base of segment 3 ( Fig. 1g′ ) and with terminal claw bearing row of spinules on lateral and medial margins ( Fig. 1g ); exopod segment 3 with two apical spines ( Fig. 1g ), longest spine extending to apex of terminal claw; endopod two-segmented, as long as exopod segment 1 or even longer, with distal row of setulae and with relatively long unequal setae: one apical and one subapical ( Fig. 1h ). Male ( Fig. 2a ). Body length 1.40–1.55 mm (n = 9). Rostrum with two strong long curved processes and one distinct lateral process ( Fig. 2c ). Left antennule extending to middle of urosome. Right antennule with spiniform projections on segments 10, 11 and 13–16; segment 13 with longest projection ( Fig. 2b ); antepenultimate segment with small hyaline process ( Fig. 2b′ , arrowed). In right leg 5 ( Fig. 2d ), coxa with elongate projection supplied with hyaline spine; basis with two well-visible hyaline processes in proximal and distal parts of medial margin and with a small hook-shaped process between them ( Fig. 2e , arrowed), with granulate (not spinulate) surface near distal process ( Fig. 2e ); exopod segment 1 wider than long, with distinct acute dilation at outer distal corner; exopod segment 2 about 1.7 times as long as wide, with strong slightly curved claw and granulate (not spinulate) surface near it ( Fig. 2f , arrowed), with lateral dentate spine inserted in distal part of lateral margin ( Fig. 2f ); endopod two-segmented, reaching one-third of proximal part of exopod segment 2, with distal brush of setulae and three apical setulae ( Fig. 2g ). In left leg 5 ( Fig. 2d ), basis slightly narrowing distally, with small lateral process near distal margin; exopod two-segmented, with thick setae in middle of segment 1 and in proximal part of segment 2; proximal part of exopod segment 1 wider than its distal part; exopod segment 2 with long dentate spine (exopod 3, according to Dussart & Defaye, 2001 ) being slightly curved in proximal part, with tiny hairs on anterior surface and with five overlapping membranous folds on distomedial surface ( Fig. 2h ); endopod two-segmented, weak.