Pliocene four-rayed discoasters from IODP Expedition 363 sites in the eastern Indian Ocean and western Pacific Ocean

International audienceThe stratigraphic distribution, occurrence and possible biostratigraphic significance of several previously-undescribed and rarely-reported four-rayed discoasters are described. The discoasters were observed in ZonesNN10 to NN18 (Upper Miocene to Lower Pleistocene) in cores recovered from International Ocean Discovery ProgramExpedition 363 sites in the eastern Indian Ocean (offshore NW Australia) and western Pacific Ocean. One ofthe discoasters is a bilaterally-symmetrical form with simple ray-tip morphology, which is herein described as thenew species Discoaster alyssae. Three new varieties are also introduced––Discoaster surculus var. pullumpedes, D.variabilis var. pacificus and D. exilis var. resolutioniae