An infant ornithopod dinosaur tibia from the Late Cretaceous of Sebeş, Romania

Introduction Since 2010 the Transylvanian Museum Society (Cluj-Napoca, Romania), the “Ioan Raica” Municipal Museum (Sebes, Romania), the University of Bucharest (Romania), the American Museum of Natural History (New York, USA), and the University of Southampton (UK) have collaborated on a project focused on the vertebrate paleontology and geology of the Late Cretaceous of the Sebes region of Romania. The aim of this project is to better understand the peculiar dinosaurbearing faunas of the European terminal Cretaceous, which included bizarre dwarfed and late-surviving relict species that inhabited an ancient island archipelago.1 The most notable result of our project thus far has been the discovery of the aberrant new dromaeosaurid theropod Balaur bondoc, a close relative of the iconic Central Asian Velociraptor mongoliensis. The type specimen of B. bondoc was discovered by M. Vremir, described by our joint Cluj-Bucharest-New York team in 2010,2 and later monographed by our group.3 Here we describe a fragmentary, but intriguing, new specimen collected during fieldwork in 2011: the tibia of a small ornithopod dinosaur that may have been less than one year old at the time of death.