Phylogenetic inferences of Tisbe Lilljeborg, 1853 (Copepoda, Harpacticoida) with Tisbe thailandensis sp. nov. from Thailand

Tisbe thailandensis sp. nov. is described in particular detail from a laboratory stock raised from individuals collected from Bangsaen Beach, Thailand. The description has revealed the following autapomorphic characters: the spiniform terminal seta of P1 Enp III bears a spinule row on anterior face; the innermost seta carries at the outer tip a tuft of spinules; the outermost seta has along its outer border short but stiff spinules; there are large surface spinules on the anterior face of female P5 exp and baseoendopod and male P5 exp. A phylogenetic inference study provides a most parsimonious hypothesis of relationships. The branching pattern indicates that Tisbe thailandensis sp. nov. is the most underived taxon compared to the remaining Tisbe species analyzed here. It confirms that T. furcata shares several characters with a number of species that justifies uniting them in a T. furcata group. According to the present analysis, the furcata group contains the following species: T. bocqueti, T. furcata, T. variana, T. carolinensis, and T. bulbisetosa. The male dimorphic maxilliped and the long spinule at the tip of the middle (terminal) spiniform seta of the male P5 exp are no longer constitutive for the furcata group of species since they are present also in other species.