Ephemeroporus barroisi (Richard, 1894)

Sinev, Artem Y. & Semenyuk, Irina I., 2021, Males and ephippial females of Oriental Chydoridae (Cladocera: Anomopoda) from Cat Tien National Park, South Vietnam, Zootaxa 4941 (3), pp. 381-398 : 394-396

Ephemeroporus barroisi (Richard, 1894)

Uncommon species in Cat Tien ( Sinev & Korovchinsky 2013). Species was abundant in localities 1 and 2, and few specimens were present in most samples from locality 3. A single ephippial female and a single adult male were found in locality 2 on 05.12.2017.

Morphology of parthenogenetic and ephippial females of E. barroisi from South-East Asia was studied by Sinev & Yusoff (2016). Morphology of Cat Tien population fully agrees with that data. Males of E. barroisi from South-East Asia were never reported, so full description of male is provided.

Male. Body ( Fig. 8E ) much lower than that of female, irregular oval in lateral view, weakly compressed laterally. Height/length ratio about 0.7, maximum height before midline. Dorsal outline evenly curved, ventral margin of valves with bulge at the middle, almost straight in both anterior and posterior half. Posteroventral corner of valves ( Fig. 8F ) with a denticle of same morphology as in females. Head with short rostrum, protruding downward. Length of rostrum about 1.5 length of antennule. Rostrum apex blunt, without any denticles at the end. Eye and ocellus of same size as in female.

Postabdomen ( Fig. 8G ) short, curved, rather narrow, narrowing distally; maximum height at preanal angle. Height about 1/3 the length. Sperm duct openings located laterally at the end of postabdomen, close to the bases of claws. Ventral margin convex. Basis of claws bordered from distal margin by weak incision. Distal margin very short. Distal angle rounded. Dorsal margin irregularly concave in distal portion, with distal portion only slightly longer than the preanal portion. Anal portion longer than postanal. Preanal angle extremely well expressed, prominent; postanal angle not defined. Marginal denticles similar in shape and size to those of female; distal group consists of 5 shorter denticles, which length decrease basally; basal group consists of 2 longer denticles, and two clusters of setulae. Lateral clusters of setulae same as in female. Postabdominal claw short, curved, two times shorter than preanal portion of postabdomen, with two thick basal spines; longer spine about 0.5 times the length of claw; shorter spine three times shorter. A pecten of spinules on dorsal side of claw; long spinule on its tip, 1.5 times longer than shorter basal spine.

Antennule ( Fig. 8H ) larger than in female, aesthetascs were not fully studied due to poor preservation; number of terminal aesthetascs unknown, a single lateral aesthetasc. Male seta long, arising at 2/3 length from the base, about 2/3 length of antennule.

Thoracic limb I ( Fig. 8 I–J) with U-shaped copulatory hook, about half length of limb itself; distal portion of copulatory hook sharpened. The IDL seta 1 absent, setae 2 and 3 of similar morphology, slender and thin; male seta curved, longer than seta 2. Unlike in most Chydoridae , copulatory brush small, consisting of a single row of five setulae. Copulatory brush seta moderately long, shorter than IDL seta 2. Unlike in most Chydoridae , anterior margin of limb with four large single setulae. Three clusters of long thin setulae on ventral face of limb under copulatory brush.

Size. In single studied adult male, length 0.21 mm, height 0.15 mm.

Taxonomic notes: This is the first full description of male for the species. Description of male from Syria provided by Yalim & Chiplak (2010) is not sufficiently detailed, but it did not disagree with our data. Males of E. barroisi clearly differ from those of other Old World species (see Alonso 1987, 1996): from E. phintonicus (Margaritora, 1969) and E. margalefi Alonso, 1987 in retaining thick long marginal denticles on postabdomen, similar to those of female, and from E. epiaphantoii Alonso, 1987 by well-defined preanal angle of postbdomen and by IDL male seta being shorter than seta 3. Unlike all these mentioned species, E. barroisi males have angular, not rounded, tip of rostrum.

Figures

FIGURE 8. Chydorus reticulatus Daday, 1898 from locality 2. Ephippial female:A, lateral view.Adult male: B, lateral view; C, rostrum; D, postabdomen.Ephemeroporus barroisi (Richard, 1894) from locality 2.Adult male: E, lateral view; F, posteroventral margin of valves; G, postabdomen; H, antennule and rostrum; I–J, thoracic limb I.