Leberis Smirnov 1989

Leberis Smirnov, 1989

Parthenogenetic female short description. Body rounded (Fig. 12 G), with a convex ventral margin; head and valves without a keel. 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. Labral keel of moderate width, with a rounded apex, without clusters of setulae on posterior margin.

Postabdomen (Fig. 12 H) of moderate length and width, narrowing distally in postanal portion, with straight distal margin and rounded distal angle; length about 2.1–2.4 heights. Preanal angle well-defined, postanal angle weakly defined. Postanal denticles small, in groups; their length not exceed width of postabdominal claw base. Postanal lateral groups of setulae of moderate length; in distalmost groups, length of setulae about the width of base of postabdominal claw. Postabdominal claw long, weakly curved, with short basal spine.

Antennule without lateral aesthetasc; all terminal aesthetascs of similar length. Antennal seta without basal peg. Antenna with thin seta on basal segment of endopodite. Spine on basal segment of exopodite as long as middle segment. Spines on apical segments about 1/3 length of apical segments. IDL of limb I with three setae (Fig. 12 I– J); seta 1 minute, rudimentary; setae 2–3 thin, armed with strong spinules.

Taxonomic notes. Two species of the genus present in the region are very similar in external morphology and can be recognized only by morphology of IDL setae.