Diagnosis. Small caenagnathid. Dentary short and deep, with tip of dentary upturned in
lateral view. Four symphyseal ridges. Short caudal symphyseal shelf. Dentary contributes to
dorsal margin of external mandibular fenestra. Dentaries strongly divergent, with posterior
rami of dentaries forming an angle of roughly 35 in dorsal view.

abstract Caenagnathid theropods are a relatively common part of the theropod fauna in the
Late Cretaceous of Asia and North America, but have not previously been described from
the southernmost United States. Here, we describe caenagnathid fossils from the late
Campanian Aguja Formation of West Texas, and revise the systematics of caenagnathids
from the Campanian of North America. Caenagnathids from the late Campanian of Canada
represent three species in three genera: Caenagnathus collinsi, Chirostenotes pergracilis …