Abstract Study of a Cenomanian–Turonian sequence, including the oceanic anoxic event 2 (OAE2) in Central Jordan, yielded 22 ostracod species from the Middle–Late Cenomanian interval; no ostracods were found in the Early Turonian. The majority of the taxa have a wide geographical distribution along the southern shores of the Tethys; from Morocco in the west to the Arabian Gulf region in the east. Biogeographical homogeneity of the ostracod associations in North Africa and the Middle East reflects facilitated communication along the whole expanse of the southern Tethys margin during the Cenomanian, and suggests similar living conditions and absence of important geographical barriers that could hinder marine faunal exchange. Biostratigraphically, the investigated fauna revealed five informal ostracod biozones (I to V from older to younger). The recorded assemblages are characterized by ostracod faunas of typical marine shelf setting in biozone I, shelf lagoonal setting with fresh-water influence in biozone II, marine shelf setting with intervals of fresh-water supply in biozones III and IV, and reduced oxygen levels in the interval of biozone V. This sequence of biozones provides palaeontological evidence for the occurrence of an interval of enhanced fresh-water influence in Levant platform lagoons preceeding OAE2. A combined biostratigraphic and chemostratigraphic time scale based on stable carbon isotopes reveals the first appearance of Reticulicosta kenaanensis , previously described as an Early Turonian indicator species already in the Late Cenomanian. Absence of ostracods throughout the Early Turonian indicates environmental conditions adverse to ostracods during most of OAE2 and its aftermath interpreted to reflect strong water column stratification.

Abstract Quantitative study of the ostracode assemblages from the Palaeocene to Early Eocene succession exposed along the area of east-central Sinai extending from the Egma Plateau in the south to Areif El Naqa in the north, using cluster analysis based on the customary presence/absence data matrix of frequencies (the Jaccard coefficient of similarity), has resulted in the distinction of five ecozones in the Early Palaeocene to Early Eocene intervals. Correspondence analysis applied to the same data matrix has led to the identification of five environmental factors affecting the distribution of the whole ostracode assemblage of the study area. These are the time factor or vertical distribution (second latent vector), water depth (third latent vector), degree of energy (fourth latent vector), water temperature as a function of depth (fifth latent vector), and oxygen concentration (sixth latent vector). From this, the prevailing palaeoenvironments in the study area during the Early Palaeocene to Early Eocene times have been reconstructed. A distinct faunal change has been detected at the Palaeocene-Eocene thermal maximum (PETM) as indicated by the second latent vector.