A new kurmademydine turtle (Pleurodira, Pelomedusoides) from the Cretaceous–Paleogene intertrappeans of Upparhatti (Karnataka), India

The timing and duration of physical connections during Indo-Pakistan’s progressive disengagement with Gondwanan landmasses during the late Mesozoic and its engagement with Asia in the early Cenozoic are expected to have profoundly influenced its terrestrial vertebrate fauna as well as that of neighboring landmasses. Paleocoastline reconstructions predict a phase of geographic isolation for Indo-Pakistan that may have lasted for tens of millions of years during the Late Cretaceous. Surprisingly, many of the terrestrial vertebrates known from that time period in India and Pakistan show biotic connections to species from other Gondwanan landmasses, such as Madagascar, South America, and Africa. Thus far, one of the few terrestrial vertebrate clades hypothesized to be endemic to Indo-Pakistan during the late Mesozoic–early Cenozoic is the side-necked turtle clade Kurmademydini, which includes species from the Late Cretaceous (Jainemys pisdurensis) and Paleocene (Sankuchemys sethnai) of central India and the Late Cretaceous of southern India (Kurmademys kallemedensis). Here we report on the discovery of a fourth member of that group, represented by a well-preserved, complete skull from intertrappean horizons in Karnataka State in south-central India that are latest Cretaceous to earliest Paleogene in age. The specimen was found in association with numerous partial and complete turtle shells that are as yet unprepared. The skull is approximately 6.5 cm long and characterized by an accessory triturating surface on the maxilla and a well-marked pterygoideus fossa. These and other features suggest close affinities with Kurmademys, Jainemys, and Sankuchemys within Kurmademydini, broadening the spatiotemporal distribution of this endemic clade.