Potential faunal evidence for western epicontinental seaway along the Narmada rift in peninsular India during the latest Cretaceous (Maastrichtian)

The pathways of marine incursions into central India around the Cretaceous-Paleogene (K-Pg) transition are a matter of ongoing debate. While there is a general consensus regarding marine incursions from the southeast coast of India along the Godavari rift, it is still highly controversial as to whether such incursions also took place from the western margin, along the Narmada-Tapti rift. Here we report the first fossil evidence (batoid and pycnodontid fishes) suggesting potential marine influences during the deposition of freshwater Deccan intertrappean sediments (late Cretaceous, Maastrichtian) in the lower Narmada valley of west-central peninsular India. The discovery of several isolated teeth of the stingray genus Igdabatis (I. indicus) along with a pycnodontid tooth in a predominantly freshwater intertrappean section at Mohanpura, district Dhar (Madhya Pradesh state) is significant, especially since living myliobatids are essential inhabitants of coastal marine ecosystems. Similar previously recorded occurrences of Igdabatis and pycnodontids from several other Maastrichtian infra- and intertrappean localities on the eastern and southeastern fringes of the Deccan Volcanic Province have been interpreted as evidence of marine incursions from India's eastern margin along the Godavari rift. The present records from district Dhar tentatively suggest the existence of a nearby epicontinental seaway (the Narmada Seaway) during the Maastrichtian. The Narmada Seaway extended hundreds of kilometres inland from India's western margin, beginning in the late Cenomanian with the deposition of long known Bagh Beds and continuing intermittently until the early Paleocene (Danian, Zone P1a). (c) 2023 Elsevier Ltd. All rights reserved.