English: Palaeogeographical reorganization of the Tethys–Paratethys region during the Paleogene, from a connected Tethys configuration during the early Eocene (a) to a fragmented and restricted Paratethys region configuration during the Oligocene (b). Note the loss of deep-water connections between the Indian Ocean region and the Mediterranean, the complete loss of Indian–Arctic Ocean connections, and the closure of most of the Eocene seaways in the Oligocene time.