Rahiolisaurus gujaratensis, n. gen. n. sp., A New Abelisaurid Theropod from the Late Cretaceous of India

Abstract

Abelisaurids are probably the most distinctive predatory dinosaurs from disjunct Gondwanan landmasses during the Cretaceous period. As far as the Indian record is concerned, abelisauroid remains have been discovered sporadically for the last 75 years from the Upper Cretaceous Lameta Formation of central and western India, immediately below the Deccan Trap lava flows. Indian abelisauroid taxa include several species that are based on fragmentary remains including Indosuchus raptorius, Indosaurus matleyi, Lametasaurus indicus, Laevisuchus indicus, and Rajasaurus narmadensis (Huene and Matley, 1933; Chatterjee, 1978; Wilson et al., 2003), but their anatomy and relationships are beginning to emerge with the description of new material and review of previous collections (Wilson et al., 2003; Novas and Bandyopadhyay, 1999, 2001; Novas et al., 2004; Carrano and Sampson, 2008). The Lameta Formation is a fluvio-lacustrine coastal plain deposit about 50 m thick, and is well known for its dinosaur fauna. In 1996, Chatterjee and Rudra reported the discovery of a dinosaur graveyard in a mudstone facies of the Lameta Formation near Rahioli village, Kheda District, Gujarat. This bone bed has yielded assorted but disarticulated dinosaur bones of abelisaurids and titanosaurs. The age of the Lameta Formation is regarded as Maastrichtian on the basis of microfossils, vertebrates, and the associated basal flows of the Deccan lavas (Sahni and Bajpai, 1991; Chatterjee and Rudra, 1996). The partial skeleton of a sympatric abelisaurid species Rajasaurus narmadensis was collected from a nearby area at the Temple Hill locality (Wilson et al., 2003). The purpose of this paper is to describe this new material of Rahiolisarus and discuss its affinity with other Gondwana abelisauroids.