A new spiral-horned antelope, Gazellospira tsaparangensis sp. nov., from Pliocene Zanda Basin in Himalaya Mountain

Abstract

Explorations in the past 20 years in the Plio-Pleistocene Zanda Basin (3,800–4,500 m above sea level) along the northern slopes of the Himalaya Mountains have substantially enriched our understanding of the paleoenvironments of the Tibetan Plateau and associated biologic evolution. Many elements of the mammalian fauna recovered are either new to science or shed new light about their special adaptations in this high elevation basin. Here we describe a new species of twisted-horned antelope, Gazellospira tsaparangensis, with a heteronymous spiral. Its small size and primitive morphology, such as relatively short horncore with less twisting, thin frontal bones, a lack of frontal and horncore sinuses, small size of supraorbital foramina, and lack of an anterior keel, helps to place it at the base of genus Gazellospira, substantially more stem-ward than the type species G. torticornis from the Plio-Pleistocene of Europe and western Asia. With an estimated age of 3.62 Ma, this also places G. tsaparangensis as one of the early occurrences in Eurasia, although some fragmentary records in Turkey may be slightly earlier. Considering this early appearance and primitive morphology, G. tsaparangensis once again may be a case of the ‘out-of-Tibet’ model of megafauna origin, with earlier progenitors adapted to cold environments in high Tibet before expanding their range to the rest of Eurasia.