Based on an extensive survey of quadrate morphology in extant and fossil bi
rds, a complete quadrate from the Maastrichrian Lance Formation has been as
signed to a new genus of most probably odontognathous birds. The quadrate s
hares with that of the Odontognathae a rare configuration of the mandibular
condyles and primitive avian traits, and with the Hesperornithidae a uniqu
e pterygoid articulation and a poorly defined (if any) division of the head
. However. the quadrate differs from that of the Hesperornithidae by a hing
e-like temporal articulation, a small size of the orbital process, a well-m
arked attachment for the medial (deep) layers of the protractor pterygoidei
et quadrati muscle, and several other details. These differences, as well
as the relatively small size of about 1.5-2.0 kg, suggest a feeding special
ization different from that of Hesperornithidae.