Eudiaptomus vulgaris ( Schmeil, 1898 )

Podshivalina, V. N., Sheveleva, N. G., Semenova, A. S. & Mirabdullayev, I. M., 2022, Eudiaptomus transylvanicus and E. vulgaris (Copepoda: Calanoida: Diaptomidae): comparative morphology, distribution and ecology, Zoosystematica Rossica 31 (1), pp. 42-54 : 47

Eudiaptomus vulgaris ( Schmeil, 1898)

( Figs 3 , 4 )

Material examined. Russia, Chuvash Republic , near Malye Shikhirdany Vill., shallow water body, 55.08648°N 47.779366°E, 28 May 2020, 4 males, 3 females (E. Kuz’min leg.) .

Redescription. Female ( Fig. 3a ). Body length 1.40–2.01 mm (n = 8). Last thoracic segment with distinct, slightly asymmetrical wings. Genital compound somite dilated in upper part, with middle-sized hyaline spines ( Fig. 3b , arrowed). Rostrum with two long acuminate curved processes ( Fig. 3c ). Antennule extending to apices of apical caudal setae ( Fig. 3a ) or even longer. Edge of mandibular incision with single-vertex teeth: one ventral and seven central. Ventral tooth separated from other teeth by deep, gently sloping diastema ( Fig. 3d ). Rather deep diastema also present between outer ventral central tooth and six other teeth. Ventral teeth single-vertex, with wide base. Three central teeth rounded, others acute ( Fig. 3d ). Dorsal teeth double-vertex, acute, with narrow base. Maxilla and maxilliped with long plumose setae increasing filtration capacity; these setae situated on sympodite compounds (precoxopodite, coxopodite), basipodite and endopodite. In leg 2, endopod segment 2 with Schmeilsche lobus ( Fig. 3i , arrowed). In leg 5, coxa with short thin lateral projection ( Fig. 3e ); exopod segment 1 rectangular, elongate, twice as long as wide ( Fig. 3f ); exopod segment 2 with spine at base of segment 3 ( Fig. 3h ) and with terminal claw bearing row of spinules on lateral and medial margins ( Fig. 3h ); exopod segment 3 with two apical spines, longest spine extending to three-fourths or to apex of terminal claw ( Fig. 3h ); endopod about two-thirds of exopod segment 1 length, with one subapical and one lateral (distal) setulae, and with one apical and one subapical relatively long unequal setae ( Fig. 3f ).

Male ( Fig. 4a ). Body length 1.40–1.50 mm (n = 5). Rostrum with two long acuminate curved processes and one lateral process ( Fig. 4e ). Left antennule extending to apex of caudal ramus. Right antennule with spiniform projections of variable shape and size on segments 10, 11 and 13–16; antepenultimate segment with small hyaline membrane and hook-shaped process ( Fig. 4b , arrowed). In right leg 5 ( Fig. 4c ), coxa with large rounded well-sclerotised distolateral projection ( Fig. 4d , arrowed); basis with small hyaline process in proximal part and with well-visible hyaline process in central part of medial margin ( Fig. 4d ); exopod segment 1 wider than long, with distinct acuminate dilation at outer distal corner and with dilation of lateral inner margin; exopod segment 2 about 1.3–1.5 times as long as wide, with strong subapically curved claw, with lateral spine inserted in middle of lateral margin; endopod one-segmented, reaching exopod segment 2, with several distal setulae. In left leg 5 ( Fig. 4d ), basis with large hook-shaped lateral process ( Fig. 4d , arrowed); exopod two-segmented, with setulae 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 spine (exopod 3, according to Dussart & Defaye, 2001) being slightly curved; endopod weak and long, reaching spine of exopod segment 2 ( Fig. 4d ).

Figures

Fig. 3. Eudiaptomus vulgaris (Schmeil, 1898), female. a – habitus, ventral view; b – genital compound somite; c – rostrum; d – mandible; e – coxa of leg 5; f – exopod 1 and endopod of leg 5; g – leg 5; h – exopods 2 and 3 of leg 5; i – endopod of leg 2, with Schmeilsche lobus. Scale bars: 0.5 mm (a), 100 µm (b), 50 µm (c, e, f, g, h, i), 20 µm (d).

Fig. 4. Eudiaptomus vulgaris (Schmeil, 1898), male. a – habitus, lateral view; b – ultimate segments of right antennule; c – leg 5; d – right leg 5 (coxa and basis) and left leg 5; e – rostrum. Scale bars: 0.5 mm (a), 200 µm (c), 300 µm (b), 50 µm (d, e).