Celsinotum Frey, 1991

Sinev, Artem Y., 2016, Key for identification of Cladocera of the subfamily Aloninae (Anomopoda: Chydoridae) from South-East Asia, Zootaxa 4200 (4), pp. 451-486 : 466

Celsinotum Frey, 1991

Parthenogenetic female short description. Body round, with convex posterior margin; head without keel; valves with well-defined keel ( Fig. 8 I). Sculpture of valves as longitudinal lines. Posteroventral angle of valves without denticles. Rostrum short, truncated. Three main head pores with narrow connection between them, lateral head pores minute ( Fig. 8 J). Labral keel of moderate width, with rounded apex, without clusters of setulae on posterior margin.

Postabdomen long and narrow, narrowing distally in postanal portion, with broadly rounded distal angle; length about 3.5 height ( Fig. 8 K). Preanal and postanal angles well defined. Postanal denticles small, their length not exceed width of postabdominal claw base. Postanal lateral groups of setulae of moderate length; in distalmost groups, length of setulae exceed the width of base of postabdominal claw. Postabdominal claw long, weakly curved, with long straight basal spine.

Antennule without lateral aesthetasc; two terminal aesthetascs very long, much longer than others. Antennal seta without basal peg. Antenna with thin seta on basal segment of endopodite ( Fig. 8 L). Spine on basal segment of exopodite about 2/3 length of middle segment. Spines on apical segments about 1/3 length of apical segments. IDL of limb I with three setae; seta 1 minute, rudimentary; setae 2–3 thin, armed with spinulae.

Single species, Celsinotum macronyx (Daday, 1898) ( Fig. 8 I–L). Length of adult female 0.41–0.52 mm. Rare species, found in lakes. Littoral species, associated with vegetation. Indo-Malaysian species, distributed in India, Sri Lanka, Indochina, South China and Indonesia ( Sinev & Kotov, 2012). For detailed description see Sinev & Kotov (2012).

Taxonomic notes. Externally, C. macronyx can be confused with Notoalona pseudomacronyx , which have similar outline of body and similar shape of postandomen, but it can be easily separated by the morphology of postabdominal claw; in N. pseudomacronyx length of basal spine is less than 1/3 length of claw, and in C. macronyx it is close to half-length of claw. Drawings of C. macronyx in Maiphae (2014) belong to N. pseudomacronyx instead.

Figures

FIGURE 8. A – C. Armatalona macrocopa (Sars, 1894). A, lateral view. B, postabdomen. C, antenna. D – F, Camptocercus vietnamensis Thanh, 1980. D, lateral view. E, postabdomen. F, postanal margin of postabdomen. G – H, Camptocercus uncinatus Smirnov, 1971. G, postabdomen. H, postanal margin of postabdomen. I – L, Celsinotum macronyx (Daday, 1898). I, lateral view. J, head pores. K, postabdomen. L, antenna. (A – C, from Sinev et al., 2007; D – F, from Sinev, 2011; G – H, from Sinev (2014); I – L, from Sinev & Kotov (2012 )).