a diferencia de otros dinosaurios terópodos

pero se consideran factores como cambios climáticos

alas no voladoras

se cree que en el caso de Xenoceratops foremostensis

un cuerno nasal más pequeño y dos protuberancias adicionales en la región de las mejillas

Desmostylus hesperus Ichthyosaurus a diferencia de otros dinosauriosDesmostylus hesperus was a semi aquatic marine mammal from the Miocene belonging to Desmostylia, an extinct order of mammals known exclusively from the North Pacific. Unlike sirenians, pinnipeds or cetaceans, desmostylians represented a distinct evolutionary lineage that has completely disappeared. They have traditionally been associated with Tethytheria, the broader evolutionary group that includes sirenians and proboscideans. The generic name means