BOLLETTINO DELLA SOCIETA PALEONTOLOGICA ITALIANA

New results on the hydrodynamic behaviour of fossil Nummulites tests from two nummulite banks from the Bartonian and Priabonian of northern Italy
Seddighi M, Briguglio A, Hohenegger J and Papazzoni CA
Settling velocities of 58 well-preserved tests of fossil Nummulites were experimentally determined using a settling tube. The tests were collected from the nummulite banks of Pederiva di Grancona (A forms of N. lyelli N. striatus, Middle Eocene) and San Germano dei Berici (A and B forms of N. fabianii, Late Eocene), both in the Berici Mts. (Veneto, northern Italy). The data were compared with estimated settling velocities that the same specimens might have had in life conditions. This was done by reconstructing their densities simulating water-filled condition and, to simulate post-diagenetic effects, under calcite-filled condition. These simulations show that A and B forms, even if they greatly diverge in shape, volume and size, still possess comparable settling velocities, and that each nummulite bank is characterized by specific hydrodynamic parameters. The use of settling velocity as a parameter to quantify the hydrodynamic behaviour of particles in seawater enables estimation of palaeoenvironmental conditions such as depth, substrate and the energy scenario. Such information is useful in obtaining further insights into the genesis of nummulite banks, the autochthony or allochthony of which is still being debated. Our results point to an autochthonous interpretation.
n. sp. from the upper Chattian of Porto Badisco (southern Apulia, Italy)
Benedetti A and Briguglio A
A new species of Rotaliidae, n. sp., is described from the upper Chattian of the Porto Badisco Calcarenites (Salento Peninsula, Southern Italy). The studied specimens are assigned to the foraminiferal genus based on the presence of vertical canals in both the ventral and dorsal side of the test, and an intraseptal canal system that evolves into marginal sutural canals. The new species differs from the type species of the genus, , in having a lower chamber lumen, and smaller dimension.