Late Cretaceous (early Turonian) dinoflagellate cysts from the Sergipe Basin, northeastern Brazil

Abstract

ABSTRACTThis paper presents the stratigraphic distribution and taxonomy of 62 dinoflagellate cyst species found in 85 samples from early Turonian strata exposed at Votorantim Quarry in northeastern Brazil. The early Turonian age assignment is based on calcareous nannofossils together with the organic-walled dinoflagellate cysts Cribroperidinium muderongense, Canningia reticulata, Florentinia resex, Impletosphaeridium williamsii, Kallosphaeridium? ringnesiorum, Trichodinium boltenhagenii and Xenascus plotei, which are commonly found in early Turonian strata. The genera Subtilisphaera and Palaeohystrichophora are emended, Palaeohystrichophora cheit is reassigned to Subtilisphaera cheit, and is considered a senior synonym of Palaeohystrichophora palaeoinfusa. Canningia reticulata is regarded as a senior synonym of Canningia senonica, and Subtilisphaera pirnaensis is regarded as a separate species from Subtilisphaera perlucida, because morphological characteristics can be used to distinguish them. In this study many cosmopolitan species were found, but we could also observe species with tethyan affinities, such as S. cheit and X. plotei. These species have restricted geographic distribution around the equator and are common in the Cenomanian to Turonian in both hemispheres.