The two taxa share a number of characteristics ( synapomorphy ) , which suggests an origin of dirus in the late Irvingtonian in the open terrain in the midcontinent .
The two taxa then later expanding eastward and displacing armbrusteri .
The two taxa share a number of characteristics ( synapomorphy ) , which suggests an origin of dirus in the late Irvingtonian in the open terrain in the midcontinent , and then later expanding eastward and displacing armbrusteri .