Dhananjay M. Mohabey

Predation upon hatchling dinosaurs by a new snake from the late Cretaceous of India.

A new snake from Upper Cretaceous rocks in India is found with hatchling sauropod dinosaurs, demonstrating that large, gape-limited snakes were probably capable of taking in moderate-sized vertebrate prey.

Systematics of Indian Upper Cretaceous dinosaur and chelonian eggshells

ABSTRACT A large number of dinosaur nesting sites have been documented from the Upper Cretaceous (Maestrichtian) Lameta Formation of India. A remarkable diversity is noticeable in the eggshells. Based on the general morphology and the histostructure, they are parataxonomically assignable to oofamily Megaloolithidae (Tubospherulithic morphotype) and Elongatoolithidae (Ratite morphotype). Ten new oospecies of these eggshells are described in the present paper. Of these, the eight oospecies are assignable to oogenus Megaloolithus, one to the newly established oogenus Ellipsoolithus and the remaining one has been categorised as Incertae sedis. In addition, associated chelonian eggshells are also described. The Indian Upper Cretaceous dinosaur fauna is dominated by the titanosaurids (sauropods), and reports of theropods (megalosaurid and tyrannosaurid) and ornithopods are. The eggs, whose shells are here attributed to a number of oospecies, must have had their parentship amongst these known dinosaurs. Many egg...

A TITANOSAURIFORM (DINOSAURIA: SAUROPODA) AXIS FROM THE LAMETA FORMATION (UPPER CRETACEOUS: MAASTRICHTIAN) OF NAND, CENTRAL INDIA

The Lameta Formation (Upper Cretaceous, Maastrichtian) of central and western India offers a glimpse of the vertebrate fauna on IndoPakistan during a critical period in its northward migration toward Asia. Vertebrate remains are preserved in the so-called “infratrappean” and “intertrappean” sediments, which lie below and within the Deccan Trap volcanic episode, respectively, and whose age has been estimated at 65 million years ago (Courtillot, 1986, 1996). These two horizons preserve quite different vertebrate fossils, despite their apparent contiguity in some places (Sahni et al., 1984). Large vertebrates, such as dinosaurs, predominate in fossiliferous infratrappean limestones and conglomerates. These are numerous but often disarticulated (e.g., Huene and Matley, 1933; Mathur and Srivastava, 1986; Mathur and Pant, 1987), although some associated (Jain and Bandyopadhyay, 1997; Wilson et al., 2003) and articulated (Mohabey, 1987) remains are known. In contrast, intertrappean marls and shales have preserved a much more taxonomically diverse microvertebrate assemblage that includes sharks (Prasad and Cappetta, 1993), amphibians and squamates (Owen 1847; Noble, 1930; Chiplonker, 1940; Prasad and Rage, 1991, 1995), turtles (Jain, 1986; Singh et al., 1998; Gaffney et al., 2001, 2003), crocodylomorphs (Prasad and de Lapparent de Broin, 2002), dinosaurs (Prasad and Sahni, 1999), and mammals (Prasad and Sahni, 1988; Prasad et al., 1994; Krause et al., 1997; Rana and Wilson, 2003). Recent reappraisals of the Cretaceous dinosaurs of India have recognized at least three large-bodied and one small-bodied theropod genera (Novas and Bandyopadhyay, 1999; Wilson et al., 2003), as well as at least two sauropod genera (Wilson and Upchurch, 2003). Despite numerous reported Cretaceous thyreophorans from India (e.g., Brachypodosaurus gravis, Chakravarti, 1934; Dravidosaurus blanfordi, Yadagiri and Ayyasami, 1979; Chatterjee and Rudra, 1996), none preserve characters that definitively place them within that clade. The putative thyreophoran recently described from Lower Jurassic sediments of Andhra Pradesh, India (Nath et al., 2002) is a crocodylomorph (K. Ayyasami and P. Yadagiri, personal communication). Indian theropods share close phylogenetic relationships with South American and Malagasy forms (Sampson et al., 1998; Carrano et al., 2002; Wilson et al., 2003) and more distant relationships with African forms (Sereno et al., 2004). Paradoxically, the genus-level relationships of Indian sauropods, which are known from more and better material, remain unresolved. This is due to the lack of phylogenetic resolution within Titanosauria rather than the quality of Indian sauropod remains, which include the partial skeleton of Isisaurus ( “Titanosaurus”) colberti (see Jain and Bandyopadhyay, 1997; Wilson and Upchurch, 2003). Recent cladistic analyses nest Isisaurus within Titanosauria, a clade that has a near-global distribution during the Cretaceous (Curry Rogers and Forster, 2001; Wilson, 2002). Below, we describe a well-preserved sauropod axis from the Nand region, central India (Fig. 1), in beds that are contiguous with those of Pisdura (Matley, 1921; Huene and Matley, 1933) and Dongargaon, where Isisaurus was discovered (Berman and Jain, 1982; Jain and Bandyopadhyay, 1997). The camellate pneumatization of the Nand axis suggests affinities with Titanosauriformes (Brachiosaurus + Titanosauria), and a second pneumatic feature links it with Saltasaurus from South America. A survey of sauropod axial morphology identifies considerable variation between genera, but few characters that unite major lineages. These results may suggest a high degree of specialization in the atlas-axis complex of sauropods. Institutional Abbreviations—AMNH, American Museum of Natural History, New York; CM, Carnegie Museum of Natural History, Pittsburgh; DGM, Museo de Divisao Geologia e Mineralogia de Departamento Nacional da Produção Mineiro, Rio de Janeiro; GSI, Geological Survey of India, Kolkata; HMN, Museum für Naturkunde der Humboldt-Universität, Berlin; IVPP, Institute for Vertebrate Paleontology and Paleoanthropology, Beijing; MACN, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Buenos Aires; PMU, Palaeontological Museum, Uppsala; PVL, Fundación Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán; UUVP, University of Utah, Salt Lake City; UMMP, University of Michigan Museum of Paleontology, Ann Arbor; USNM, United States National Museum, Washington D. C.; ZDM, Zigong Dinosaur Museum, Zigong.

A new species of the snake Madtsoia from the Upper Cretaceous of India and its paleobiogeographic implications

ABSTRACT We report the discovery of a new species of the snake Madtsoia from1 infratrappean horizons of Late Cretaceous age in Pisdura, central India. Recovered vertebrae are large (1.83 cm long; 4.35 cm tall) and pertain to a snake that was ca. 5 m long. Discovery of Madtsoia in India extends the geographic distribution of the genus and represents only the second species known from the Cretaceous. Vertebrae of Madtsoia pisdurensis sp. nov. are strikingly similar to those of M. bai and M. camposi (South America) and M. madagascariensis (Madagascar), but can be distinguished from them by a unique process on the hemal keel, which is low, flat, and triangular in outline. Whereas the eastern Gondwanan species of Madtsoia (M. madagascariensis, M. pisdurensis) are Late Cretaceous in age, the western Gondwanan species (M. bai, M. camposi) are Paleogene in age. Geophysical evidence suggests that land connections between South America, Madagascar, and Indo-Pakistan were severed by at least 100–90 Ma, which implies that Madtsoia achieved its broad geographic distribution either by (1) origin and dispersion before the end of the Turonian; or (2) the presence of an unrecognized land connection persisting into the latest Cretaceous. Both hypotheses predict that Madtsoia will be discovered in Mesozoic strata of South America, where it survived the Cretaceous-Paleogene mass extinction.

No K/T boundary at Anjar, Gujarat, India: Evidence from magnetic susceptibility and carbon isotopes

The paper describes the variation pattern of magnetic susceptibility of Lameta sediments and isotopic variation of organic13C from Chui Hill, Bergi, Kholdoda, Pisdura and Girad. The susceptibility pattern and a negative carbon isotopic anomaly allows fixation of the K/T boundary at these localities and they differ in these aspects from the inter-trappean sediments at Anjar.Paleomagnetic measurements of the Anjar sediment and the overlying basalt flow demonstrate reversed polarity. The Lameta sediments with dinosaur nests at Kheda and the overlying intertrappean sediments are of normal polarity.The clay layers at Anjar, associated closely with Ir-enrichments, are strongly leached, rhyolitic bentonites containing low-quartz paramorphs after high-quartz with glass inclusions.It is concluded, that the inter-trappean lake deposits at Anjar were deposited in the early part of magnetochron 29R and are unrelated to the K/T boundary.

Palynology and clay mineralogy of the Deccan volcanic associated sediments of Saurashtra, Gujarat: Age and paleoenvironments

The intertrappean sediments associated with Deccan Continental Flood Basalt (DCFB) sequence at Ninama in Saurashtra, Gujarat yielded palynoassemblage comprising at least 12 genera and 14 species including Paleocene taxa such as Intrareticulites brevis, Neocouperipollis spp., Striacolporites striatus, Retitricolpites crassimarginatus and Rhombipollis sp. The lava flows of Saurashtra represent the northwestern most DCFB sequence in India. It is considered that the Saurashtra lava flows represent the earliest volcanic activity in the Late Cretaceous of the Reunion Mantle Plume on the northward migrating Indian Plate. The present finding of the Paleocene palynoflora from Ninama sediments indicate Paleocene age for the associated lava flows occurring above the intertrappean bed which suggests that the Saurashtra plateau witnessed eruption of Deccan lava flows even during Paleocene. The clay mineral investigation of the Ninama sediments which are carbonate dominated shows dominance of low charge smectite (LCS) along with the presence of mica and vermiculite. Based on the clay mineral assemblage it is interpreted that arid climatic conditions prevailed during the sedimentation. The smectite dominance recorded within these sediments is in agreement with global record of smectite peak close to the Maastrichtian–Paleocene transition and climatic aridity.

Microflora from sauropod coprolites and associated sediments of Late Cretaceous (Maastrichtian) Lameta Formation of Nand-Dongargaon basin, Maharashtra

Micofloral study of Lameta sediments and associated sauropod coprolites in the Nand-Dongargaon basin in Maharashtra was conducted to understand the diet and habitat of sauropods. The study revealed the presence of pollen, spores, algal and fungal remains, well-preserved cuticles of Poaceae, and testate amoebae. Vegetation during Lameta included tall arboreal taxa, such as conifers (Podocarpus and Araucaria), Cycads (Cycas), Euphorian and Barringtonia and herbs and shrubs, such as Cheirolepidiaceae (Classopollis), Arecaceae (Palmaepollenites), Poaceae (Graminidites), Asteraceae (Compositoipollenites), Caryophyllaceae (Cretacaeiporites and Periporopollenites), and Acanthaceae (Multiareolites). Data suggest that the sauropods ate soft tissues of angiosperms and gymnosperms. The intake of testate amoeba, algal remains, sponge spicules, and diatoms might be through water intake.