Plio-Pleistocene planktic foraminiferal isotopes of IODP Site 356-U1459

This dataset reports the isotope composition (carbon and oxygen isotopes) of planktonic foraminiferal (Trilobatus sacculifer), extracted from sediment samples from IODP Site U1459. The analyzed samples have a temporal coverage from the late Pliocene to the early Pleistocene (4 - 2 Ma), and were obtained from the Perth Basin (offshore southwestern Australia). Therewith, Site U1459 is ideally situated to record changes in Leeuwin Current dynamics, and this dataset has been obtained to study Leeuwin Current intensity on orbital glacial-interglacial timescales across the Plio-Pleistocene boundary. All samples were measured using a Finnigan MAT 251 gas isotope ratio mass spectrometer connected to a Kiel III automated carbonate preparation device at the Center for Marine Environmental Sciences (MARUM), between 2018 and 2021

Genetic and morphological divergence in the warm-water planktonic foraminifera genus <i>Globigerinoides</i>

The planktonic foraminifera genus Globigerinoides provides a prime example of a species-rich genus in which genetic and morphological divergence are uncorrelated. To shed light on the evolutionary processes that lead to the present-day diversity of Globigerinoides, we investigated the genetic, ecological and morphological divergence of its constituent species. We assembled a global collection of single-cell barcode sequences and show that the genus consists of eight distinct genetic types organized in five extant morphospecies. Based on morphological evidence, we reassign the species Globoturborotalita tenella to Globigerinoides and amend Globigerinoides ruber by formally proposing two new subspecies, G. ruber albus n.subsp. and G. ruber ruber in order to express their subspecies level distinction and to replace the informal G. ruber “white” and G. ruber “pink”, respectively. The genetic types within G. ruber and Globigerinoides elongatus show a combination of endemism and coexistence, with little evidence for ecological differentiation. CT-scanning and ontogeny analysis reveal that the diagnostic differences in adult morphologies could be explained by alterations of the ontogenetic trajectories towards final (reproductive) size. This indicates that heterochrony may have caused the observed decoupling between genetic and morphological diversification within the genus. We find little evidence for environmental forcing of either the genetic or the morphological diversification, which allude to biotic interactions such as symbiosis, as the driver of speciation in Globigerinoides