Tropodiaptomus sirindhornae sp. nov., A New Diaptomid Copepod (Copepoda: Calanoida) from Thailand

Tropodiaptomus sirindhornae sp. nov. is described and illustrated based on materials collected from both permanent and temporary habitats across several regions of Thailand. This new species can be distinguished from its congeners by the following morphological characters of adult male antennule and fifth leg: the antepenultimate segment of right antennule with straight spinous process reaching between 1/2 and 3/4 of next segment; the inner margin of exopodal segment of left fifth leg with two lobes, and with uniform serration; the basis of right fifth leg has one triangular process and one longitudinal hyaline lamella; and second exopodal segment of right fifth leg is rectangular, posterior surface ornamented with one semicircular hyaline knob on middle close to inner margin and one triangular apophysis on distal outer margin. This species is widely distributed both spatially and temporally.