The forelimbs of Anchiornis were also very long , unusual among troodontids ( which tend to be short-armed ) but similar to dromaeosaurids and early birds , emphasizing its basal ( ` primitive ' ) position among dinobirds . The forelimbs of Anchiornis were also very long , unusual among troodontids ( which tend to be short-armed ) but similar to dromaeosaurids and early birds , emphasizing its basal ( `` primitive '' ) position among its relatives .