Zephyrosaurus

Zephyrosaurus (meaning "westward wind lizard") is a genus of hypsilophodont ornithopod dinosaur. It is based on a partial skull and postcranial fragments discovered in the Aptian-Albian-age Lower Cretaceous Cloverly Formation of Carbon County, Montana. New remains are under description, and tracks from Maryland and Virginia have been attributed to something like it.

Description
Zephyrosaurus is still very incompletely known. Among other distinctive characteristics, it had a steep face, a raised knob on the upper jaw, and a larger knob on the cheekbone. Some of the bones may have allowed movement within the skull (cranial kinesis) as well. Like other hypsilophodonts, it had beak teeth.

Classification
Several studies have suggested that Zephyrosaurus and Orodromeus are closely related, mostly by virtue of both having bosses (described informally as "somewhat like an altoid") on their cheeks.[2][3] Other studies have had difficulty classifying it, due to the sparseness of the original material.[4] Oryctodromeus also shares several characteristics with Zephyrosaurus and Orodromeus, some of which may be related to burrowing. Thus, there may be a possible clade of burrowing hypsilophodonts from the middle to Late Cretaceous of Montana.