A new coralloid arecoid palm root mat from the Deccan Intertrappean Beds of India and its significance

A new fossil-species of coralloid palm root mat under the organ genus Rhizopalmoxylon is reported from the latest Maastrichtian (Late Cretaceous) to earliest Danian (Early Palaeocene) sediments (c. 66–65Ma) of the Deccan Intertrappean Beds of Madhya Pradesh, Central India. The significant anatomical attributes, specifically an exodermis comprising 2–4 layered parenchymatous cells; a 5–8 layered homogeneous outer cortex, a highly lacunate inner cortex central diffuse layer of aerenchyma with well-developed radially elongated cells arranged in 2–4 rows, and a stele consisting of radial and exarch vascular bundles with proto and metaxylem strands reveal its close resemblance to root mats of extant taxa of the palm subfamily Arecoideae. The Deccan intertrappean root mat is described here as Rhizopalmoxylon arecoides Kumar, et Khan sp. nov. This new species adds to the late Cretaceous - early Palaeocene palm fossil record of India when it was still relatively geographically isolated in the southern hemisphere tropics. This fossil evidence and previously reported other arecoid palm taxa from the same fossil horizon collectively suggest a subtropical to tropical climate in the area during the time of the deposition.