Ostracods from the Barbalha and Crato formations, Aptian of the Araripe Basin, northeast Brazil.

Abstract

Ostracods have been widely used for biostratigraphic and paleoenvironmental purposes for the Lower Cretaceous deposits of northeastern interior Brazilian basins. The ostracods of the Romualdo and Crato formations of the Araripe Basin are particularly well known; however, the ones from the underlying Barbalha Formation are less so. Here we report 10 ostracod species, of which three are new, obtained from 56 samples of the Barbalha and Crato formations collected from boreholes 1PS-06-CE and 1PS-10-CE: Candonopsis? alagoensis Tomé et al., 2014, Brasacypris subovatum Do Carmo et al., 2013, Damonella medialtis sp. nov., Cypridea araripensis Silva, 1978, Pattersoncypris cf. P. angulata (Krömmelbein & Weber, 1971), Pattersoncypris micropapillosa Bate, 1972, Pattersoncypris salitrensis (Krömmelbein & Weber, 1971), Pattersoncypris trapezium sp. nov., Looneyellopsis? sagittensis sp. nov., and Theriosynoecum silvai (Silva, 1978). Preservation of this material was very good in the Crato Formation and the Batateira Beds, with numerous well-preserved juvenile carapaces down to the A-6 instar having been found in the latter. Conversely, preservation was very poor in the upper portion of the Barbalha Formation, from which mostly molds were recovered.