A long Late Quaternary sedimentary record from Lake Kopais, central Greece, has yielded assemblages of ostracod shells amongst which are discrete horizons of Tyrrhenocythere donetziensis. To date, this species has been little recorded in the region. We provide details of the species' occurrence and ecology and examine its validity as a palaeoecological and palaeobiogeographical marker. Although Lake Kopais has been artificially drained, a continuous record of climate change extending well beyond the onset of the last glacial has been recorded in calcareous sediments taken from the deepest part of the basin (core K93). Ostracod assemblages occur through most of the core, however, T. donetziensis is present only in the lower part. The evidence from this study of core K93 suggests that warm, humid conditions in the catchment may be one of the limiting factors for the occurrence of this particular species of Tyrrhenocythere.