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| Bisticeratops froeseorum Dalman, Jasinski & Lucas, 2022 |
A nearly complete skull of a new ceratopsid dinosaur, Bisticeratops froeseorum, is described from the Farmington Member of the Kirtland Formation (late Campanian, Upper Cretaceous) of New Mexico. Bisticeratops is distinguished by several diagnostic cranial characters, including those of the premaxilla (stepped dorsal margin), maxilla (short jugal process lacking the ventral pocket-like fossa), jugal (short maxillary process of the jugal), and palpebral ornamentation (short with moderate ornamentation). It differs from other known chasmosaurines, especially from stratigraphically older species in the same geographic region, Pentaceratops sternbergi and Titanoceratops ouranos, by a strongly reduced jugal process of the maxilla and an unusual maxilla/jugal contact, which forms a shallow, triangular-shaped lateroposteriorly concave sulcus. A phylogenetic analysis recovers Bisticeratops froeseorum as sister species to the unnamed Almond Formation chasmosaurine and as a member of a potentially new southern clade of chasmosaurines, outside the Triceratopsini, and distinct from other southern Laramidian chasmosaurines such as Pentaceratops. The dinosaur fauna of the Farmington Member is comparatively poorly understood, especially compared to stratigraphically older faunas in the San Juan Basin. Therefore, the new, presumably rare species Bisticeratops froeseorum, together with several recently named and described chasmosaurines such as Navajoceratops sullivani, Sierraceratops turneri, and Terminocavus sealeyi, add to the diversity and disparity of chasmosaurines and provides further support for latitudinal variation in the ceratopsid fauna during the Late Cretaceous interval in the Western Interior Basin of North America.
Sebastian Dalman, Steven E. Jasinski and Spencer G. Lucas. 2022. A New Chasmosaurine Ceratopsid from the Upper Cretaceous (Campanian) Farmington Member of the Kirtland Formation, New Mexico. New Mexico Museum of Natural History and Science Bulletin. 90: 127–153.
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