A challenge to all of these alternative scenarios came when Turner and colleagues in 2007 described a new dromaeosaurid , Mahakala , which they found to be the most basal and most primitive member of the Dromaeosauridae , more primitive than Microraptor .
A challenge to all of these alternative scenarios came when Turner and colleagues in 2007 described a new dromaeosaur , Mahakala , which they found to be the most basal and most primitive member of the Dromaeosauridae , more primitive than Microraptor .