New rodents shed light on the age and ecology of late Miocene ape locality of Tapar (Gujarat, India)
The Miocene ape (Sivapithecus) locality of Tapar in Kutch (Gujarat, India) has yielded a diverse rodent assemblage that includes: a new murine Progonomys prasadi sp. nov., a new gerbilline Myocricetodon gujaratensis sp. nov., a new rhizomyne Kanisamys kutchensis sp. nov. and a new sciurine Tamias gilaharee sp. nov., beside additional remains of Progonomys morganae, Dakkamys asiaticus, Prokanisamys sp., Sayimys sivalensis and Democricetodon fejfari. Morphometric and PAUP based phylogenetic analyses place Progonomys prasadi sp. nov. within the Progonomys lineage. The cladogram obtained for the Siwalik murines suggest that Progonomys was ancestral to all the modern and one extinct murine genera recovered from the Siwaliks. The advanced features of Myocricetodon gujaratensis sp. nov. indicate that it was an immigrant to the subcontinent in the late Miocene. The cladistic analysis performed on Kanisamys kutchensis sp. nov. shows that it shared several advanced characters with contemporaneous Kanisamys nagrii and Kanisamys sivalensis. Based on the biostratigraphical ranges of Siwalik rodents and the co-occurrence of advanced forms of new and already reported murines, a new gerbilline and a new sciurine, we propose an age of ∼10 Ma to the primate-bearing Tapar locality. Already reported stable isotope data on murines, and ecological preferences of modern counterparts of the fossil rodents and associated sharks and rays from Tapar locality, indicate that the Miocene ape Sivapithecus may have lived in a subtropical monsoonal forest close to the coast, very different from the present day arid conditions.