Holmes, R. B. Mallon, J. C. Ryan, M. J. Evans, D. C. 2026 New information on the holotype of "<em>Chasmosaurus</em>" <em>russelli</em> (Ornithischia: Ceratopsidae) necessitates the establishment of a new genus to receive the species Canadian Journal of Earth Sciences 63 1-20 Hypsilophodon_foxii Lesothosaurus_diagnosticus Stegoceras_validum Homalocephale_calathocercos Prenocephale_prenes Yinlong_downsi Hualianceratops_wucaiwanensis Xuanhuaceratops_niei Chaoyangsaurus_youngi Psittacosaurus_xinjiangensis Psittacosaurus_gobiensis Psittacosaurus_major Psittacosaurus_lujiatunensis Psittacosaurus_mongoliensis Psittacosaurus_sinensis Psittacosaurus_meileyingensis Psittacosaurus_sibiricus Mosaiceratops_azumai Beg_tsi Liaoceratops_yanzigouensis Aquilops_americanus Archaeoceratops_yujingziensis Yamaceratops_dorngobiensis Auroroceratops_rugosus Archaeoceratops_oshimai Cerasinops_hodgskissi Montanoceratops_cerorhynchus Udanoceratops_tschizhovi Prenoceratops_pieganensis Zhuchengceratops_inexpectus Leptoceratops_gracilis Protoceratops_hellenikorhinus Protoceratops_andrewsi Protoceratops_sp_IGM_100_dash_1246 Breviceratops_kozlowskii Bagaceratops_rozhdestvenskyi Ajkaceratops_kozmai Graciliceratops_mongoliensis Turanoceratops_tardabilis Zuniceratops_christopheri Diabloceratops_eatoni Machairoceratops_cronusi Menefeeceratops_sealeyi Yehuecauhceratops_mudei Xenoceratops_foremostensis Crittendenceratops_krzyzanowskii Nasutoceratops_titusi Avaceratops_lammersi_type Avaceratops_sp_MOR_692 Avaceratops_sp_CMN_8804 Lokiceratops_rangiformis Albertaceratops_nesmoi Medusaceratops_lokii Wendiceratops_pinhornensis Sinoceratops_zhuchengensis Coronosaurus_brinkmani Spinops_sternbergorum Centrosaurus_apertus Styracosaurus_albertensis Styracosaurus_ovatus Stellasaurus_ancellae Einiosaurus_procurvicornis Iddesleigh_pachyrhinosaur Achelousaurus_horneri Pachyrhinosaurus_lakustai Pachyrhinosaurus_perotorum Pachyrhinosaurus_canadensis Mercuriceratops_gemini Regaliceratops_peterhewsi Kosmoceratops_richardsoni Vagaceratops_irvinensis Spiclypeus_shipporum Chasmosaurus_belli Mojoceratops_kaiseni Agujaceratops_mavericus Agujaceratops_mariscalensis Chasmosaurus_russelli_original Chasmosaurus_russelli_updated Utahceratops_gettyi Pentaceratops_sternbergii Anchiceratops_ornatus Arrhinoceratops_brachyops Eotriceratops_xerinsularis Torosaurus_latus Torosaurus_utahensis Triceratops_horridus Triceratops_prorsus Navajoceratops_sullivani Osteology Maximum Parsimony Based on reanalysis of the original matrix. Holmes_etal_2026a