A REEXAMINATION OF THE PLIENSBACHIAN AND TOARCIAN OSTRACODA OF ZAMBUJAL, WEST-CENTRAL PORTUGAL

Pliensbachian and Toarcian Ostracoda first described by Exton (Geologi cal Paper, Carleton University, Ottawa, 79: 1-104 1959) from the Lusit anian Basin, west-central Portugal have been re-examined. As a result, a greater diversity in the Ostracoda (80 species) is now recognized. Two species are newly described (Eucytherura zambujalensis sp. nov., E ktyphocythere mediodepressa sp. nov.) from the marls and calcareous sh ales of the Maria Fares Hill section near the village of Zambujal. Poo r preservation precludes a complete taxonomic review of the present ma terial. Five ostracod zones are proposed; Gammacythere ubiquita-Ogmoco nchella gruendeli Zone, Polycope cerasia-Polycope cincinnata Zone, Lia sina lanceolata-Ogmoconcha convexa Zone, Bairdiacypris rectangularis-K inkelinella sermoisensis Zone, and Cytherella toarcensis-Kinkelinella costata Zone. Although the ostracod assemblages possess strong similar ities to those described from Northwest Europe, some of the Zambujal a ssemblages are dominated by the genus Polycope. A marked faunal turnov er, in association with the extinction of the Metacopina occurs in the lower Subzone of the tenuicostatum Zone of Lower Toarcian age. These faunal events are discussed in relation to changing environmental cond itions.