First records and potential palaeoecological significance 3 of Dianella ( Xanthorrhoeaceae ) , an extinct representative 4 of the native flora of Rapa Nui ( Easter Island ) 5

9 Abstract Easter Island, a remote island in the Pacific 10 Ocean, is currently primarily covered by grasslands, but 11 paleoecological studies have shown the former presence of 12 different vegetation. Much of its original biota has been 13 removed during the last two millennia, most likely by 14 human activities, and little is known about the native flora. 15 Macrofossil and pollen analyses of a sediment core from 16 the Raraku crater lake have revealed the occurrence of a 17 plant that is currently extinct from the island: Dianella cf. 18 intermedia/adenanthera (Xanthorreaceae), which grew and 19 disappeared at the Raraku site long before human arrival. 20 The occurrence of Dianella within the Raraku sedimentary 21 sequence (between 9.4 and 5.4 cal. kyr B.P.) could have 22 been linked to the existence of favorable paleoenviron23 mental conditions (peatland rather than the present-day 24 lacustrine environment) during the early to mid Holocene. 25 This finding contributes new knowledge about indigenous 26 plant diversity on Easter Island and reinforces the useful27 ness of further macrofossil and pollen analyses to identify 28 native species on Easter Island and elsewhere. 9