Trunk segmentation of some podocopine lineages in Ostracoda

The trunk segments of podocopine ostracods, which have previously been rega rded as having a non-segmented body, are comprehensively illustrated in som e lineages for the first time. Descriptions are given of the trunk segmenta tion of representatives from eight podocopine families: Bairdiidae, Eucythe ridae, Leptocytheridae, Cytheridae, Hemicytheridae, Cytheruridae, Loxoconch idae and Xestoleberididae. As observed in the family Leptocytheridae, the m aximum number of segments in the Podocopina examined is 11. The boundary be tween the thorax and abdomen of Podocopina is not distinct. It was found th at in Podocopina, the paired copulatory organs are derived from between the fifth and seventh most terminal segments in females and the second most te rminal segment in males. It is suggested that the female body plan of Podoc opina is plesiomorphic because it is common to platycopid structure and app roximately satisfies the supposed ground plan of the Maxillopoda.