Vivesh V. Kapur

The oldest Asian record of Anthropoidea

Undisputed anthropoids appear in the fossil record of Africa and Asia by the middle Eocene, about 45 Ma. Here, we report the discovery of an early Eocene eosimiid anthropoid primate from India, named Anthrasimias, that extends the Asian fossil record of anthropoids by 9–10 million years. A phylogenetic analysis of 75 taxa and 343 characters of the skull, postcranium, and dentition of Anthrasimias and living and fossil primates indicates the basal placement of Anthrasimias among eosimiids, confirms the anthropoid status of Eosimiidae, and suggests that crown haplorhines (tarsiers and monkeys) are the sister clade of Omomyoidea of the Eocene, not nested within an omomyoid clade. Co-occurence of Anthropoidea, Omomyoidea, and Adapoidea makes it evident that peninsular India was an important center for the diversification of primates of modern aspect (euprimates) in the early Eocene. Adaptive reconstructions indicate that early anthropoids were mouse–lemur-sized (≈75 grams) and consumed a mixed diet of fruit and insects. Eosimiids bear little adaptive resemblance to later Eocene-early Oligocene African Anthropoidea.

Eocene and Oligocene sirenians (Mammalia) from Kachchh, India

Abstract Discoveries of three species of Eocene sirenians in District Kachchh, State of Gujarat, India, are reported. A species of the protosirenid Protosiren is represented by cranial and postcranial material, and the halitheriine dugongid Eosiren is represented by a poorly preserved mandible. Neither of these can be identified at the specific level. A new species of haltheriine dugongids is described: Eotheroides babiae, n. sp. The species is based on a lower jaw with teeth. Another new fossil sirenian is reported from the Oligocene (Chattian) Maniyara Fort Formation. The new species, Bharatisiren indica, n. sp., is based on a well-preserved skull, mandibles, and several postcranial specimens. Bharatisiren is a basal dugongine dugongid, close to previously described Bharatisiren kachchhensis and possibly near the origin of the modern genus Dugong.

Advent of Strong South Asian Monsoon by 20 Million Years Ago

The monsoonal paleoclimate of India has been critical for understanding the tectonic history of Himalayan and Tibetan uplift over the past 60 My. Monsoonal circulation in deep time has been inferred from variation in stable isotopes of tooth enamel, diatom blooms, and dust influx in the Indian Ocean and the advent of C4 grasses, but these proxies are compromised by temperature, biotic, and source effects. Our study uses a proxy of carbonate distribution within paleosol profiles to infer appearance of monsoonal circulation of modern strength in the Himachal Pradesh segment of the Himalayan foreland by at least 20 My ago, cued to High Himalayan deformation and ongoing Tibetan Plateau uplift and retreat of the Paratethys Sea. Paleosol records also demonstrate declining chemical weathering with Himalayan and Tibetan uplift, which was a force for global warming, rather than cooling, over the past 20 My.