Eutherian tarsal bones from the Late Cretaceous of India

Abstract

Eutherian tarsal bones of Late Cretaceous age are reported for the first time from sedimentary beds intercalated with the Deccan Traps of peninsular India. The tarsal bones, represented mainly by calcanea and astragali, occur in association with dental elements of palaeoryctid mammals: Deccanolestes hislopi Prasad and Sahni and D. robustus Prasad, Jaeger, Sahni, Gheerbrant, and Khajuria. Two size variants in the tarsals correlate well with the teeth of D. hislopi and D. robustus. Morphologically, the tarsal complex of Deccanolestes is quite different from that of other Cretaceous eutherians for which the relevant anatomy is known (Protungulatum and Procerberus). Rather, the tarsals of Deccanolestes exhibit a close affinity to the tarsal morphology of Archonta. A large number of tarsal characters indicate a highly arboreal mode of life for these animals. Presence of such specialized animals as early as the Cretaceous suggests that mammals had already diversified their locomotor adaptations by this time.