Contribution to the knowledge of the freshwater Ostracoda fauna in continental Portugal, with an updated checklist of Recent and Quaternary species

Abstract

Ostracods have a ubiquitous distribution, a high diversity of life history strategies and an extensive fossil record. These characteristics make the group a useful study tool in multiple disciplines. In Portugal, very few studies on recent freshwater ostracods have been published. This is particularly important given the need for an accurate database of both autoecology and geographical distribution of the extant species for a correct use of these crustaceans as environmental proxies. Six temporary ponds were periodically sampled during the wet season 2005/2006, in the natural park "Parque Natural do Sudoeste Alentejano e Costa Vicentina" (PNSACV) north of Vila Nova de Milfontes, SW Portugal. The relationship between ostracod assemblages and habitat features was analysed. In parallel, to assess relative ostracod species richness and diversity, faunistic results are also presented based on a regional (Alentejo) survey carried out during the same season. The semi-permanent nature of the study area in PNSACV may contribute to the observed relative high ostracod richness. Yet other environmental factors, such as pH and pond hydroperiod variation, may restrict the local ostracod species distribution and its abundance. The most abundant and/or common ostracod species were eurytopic forms: Cypridopsis vidua, Cypris bispinosa and Herpetocypris chevreuxi. A total of 14 species was identified, of which three named and one most probably undescribed candonid species new to Portugal: Bradleycypris obliqua, C. bispinosa, Paralimnocythere psammophila and Fabaeformiscandona sp. ex gr. fabaeformis. In the regional survey nine species were identified. Heterocypris sp., Ilyocypris aff. lacustris and Tonnacypris lutaria were recorded in the regional survey but not present in PNSACV, with the latter two also new in Portugal. To favour further faunistic and ecological research on ostracods in Portugal, a distributional checklist of Recent and Quaternary freshwater inland Ostracoda known from Portuguese mainland is given.