Cocoseae: A dominant arecoid palm element in the Deccan K-Pg flora of Madhya Pradesh, Central India

Abstract

Here, we report the occurrence of a large number of fossil fruits with distinctive germination pores along with a petrified stem, resembling morphologically and anatomically the extant palm tribe Cocoseae Mart. ex Dumort. of the subfamily Arecoideae. The permineralized fruits and locule casts, assigned to Palmocarpon drypeteoides (Mehrotra, Prakash, and Bande) Manchester et al., and the stem of Palmoxylon sp. were recovered from the Deccan Intertrappean Beds (late Mastrichtian–early Danian sediments; c. 66–65 Ma) of Umariya Ryt. village in Dindori District, Madhya Pradesh, Central India. Using micro–computed tomography (mCT) and standard thin section methods, we observed for the first time that these fossil palm fruits have a persistent basal trimerous perianth. These fossils, along with other reports in the literature, suggest that cocosoid palms were dominant among the arecoid palms of the Deccan Intertrappean beds in Madhya Pradesh. At present, the modern relatives do not grow in the same area but they occur in tropical forests of southeastern and eastern India as well as other regions including parts of South America, Asia, Europe, and Africa. The expansions and retraction of the cocosoid palms likely coincide with climate change. The recovery of cocosoid fossils (present and earlier reported) and previously described tropical elements from the same fossil locality suggest the existence of tropical climatic conditions during the period of depositions. We also revisit the historical phytogeography of the cocosoid palms.