 M1 is flat @-@ crowned . The anteroloph , a crest at the front of the tooth , lacks a smaller accessory spur that is present in N. rufus . The paracone , one of the main cusps , is quite small ; this cusp is more prominent in N. rufus . The mesoloph , a crest on the middle of the tooth , is distinct but short and located further to the back than in N. rufus . M2 has a longer mesoloph . M3 is largely flat @-@ crowned , but the paracone is a bit more prominent than the rest . The valley between the cusps at the front is deeper than the valleys at the back . Each of the upper molars has three roots . 
