Selandian

The Selandian was introduced in scientific literature by Danish geologist Alfred Rosenkrantz in 1924.

It is slightly after the first appearances of many new species of the calcareous nanoplankton genus Fasciculithus (F. ulii, F. billii, F. janii, F. involutus, F. tympaniformis and F. pileatus) and close to the first appearance of calcareous nanoplankton species Neochiastozygus perfectus.

[7] This change occurs at the same time as the onset of a foreland basin formation in Spitsbergen due to compression between Greenland and Svalbard,[8] suggesting a common tectonic cause that altered the relative motions of the Greenland Plate and the Eurasian Plate.

This plate reorganisation event is also manifest as a change in seafloor spreading direction in the Labrador Sea around this time.

[9] The fauna of the Selandian consisted of giant snakes (Titanoboa),[10] crocodiles, champsosaurs, Gastornithiformes,[11] owls; and a few archaic forms of mammals, such as mesonychids, pantodonts, primate relatives plesiadapids, and multiberculates.

The Global Boundary Stratotype Section and Point (GSSP) marking the lower boundary of the Selandian at Itzurun, Spain