Torosaurus
However, latest thinking is that the two are definitely different genera.<ref>Bowdler, Neil 2012. BBC News Science & Environment. Triceratops and Torosaurus dinosaurs 'two species, not one''' </ref> In 2011, 2012 and 2013, studies of external features of known specimens decided that shape and development differences mean the two genera are not synonyms. The main problems in the "one genus" idea are: Farke A.A. 2011. Anatomy and taxonomic status of the chasmosaurine ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A. PLoS ONE 6 (1): e16196.