TABLE 7. Summary of major differences between Hesperolagomys species.

	Character	H. fluviatilis	H. niobrarensis	H. galbreathi
	Age range	Ba2a-b	Ba2c	Cl2-3
	Size (in most dimensions)	small	large	intermediate
	p3 size	large	intermediate	small
	Anterolingual groove on p3	absent	weak but cement-filled	strong and cement-filled
	Lower molariform talonid shape	asymmetrical	asymmetrical	symmetrical
	p4 trigonid width/talonid width	relatively narrow	intermediate	relatively wide