Caleb Lewis wrote-
What is the earliest known Dromaeosaurid? D. Antirrhopus?
Undescribed forms known from teeth found in the Early Jurassic Hanson Formation of Antarctica (Ford, this list), the Bathonian of Russia (Novikov 1998) and England (Benton 1993), the early Kimmeridgian Portugal (Zinke 1998) and the Kimmeridgian-Tithonian Morrison Formation of Utah and Colorado (Britt 1991; Chure, Madsen and Britt 1993). The earliest named dromaeosaurid is Nuthetes destructor from the Berriasian of England.