| Bravoceratops polyphemus (gen. et sp. nov.) is a large, chasmosaurine ceratopsid from the lowermost strata of the Javelina Formation (early Maastrichtian) of Big Bend National Park, Texas. B. polyphemus has a distinctive narrow snout, a long fenestrated frill, and a fan-shaped median parietal bar with a midline epiparietal on its posterior margin, as well as a symmetrical depression on its dorsal surface at the nexus of the parietal rami. This depression is interpreted to be the attachment point for a second midline epiparietal. This parietal morphology is distinct from that exhibited by related chasmosaurines Anchiceratops and Pentaceratops. The posterior midline epiparietal in B. polyphemus and its bifurcated quadratojugal-squamosal joint are features shared with the most derived chasmosaurines Torosaurus and Triceratops. The combination of traits exhibited by B. polyphemus indicates that the phylogenetic and biogeographic history of chasmosaurines is likely more complicated than depicted in many current phylogenetic analyses. |
