Species diagnosis

• Third upper unicuspid only slightly smaller than the fourth
• Skull length usually greater than 18mm
• Hind foot length greater than 18mm
• Hind foot bordered by stiff hairs
• Height of coronoid process more than 4.3mm
  
• Length of coronoid-condyloid processes usually more
  than 3.6mm
  
• Depth of dentary below m1 + height of coronoid
  process more than 5.3mm

Alaska subspecies