▁the ▁United ▁States , ▁the ▁only ▁species ▁in ▁the ▁genus ▁A pe om yo ides . ▁It ▁is ▁known ▁from ▁fragment ary ▁j aws ▁and ▁isolated ▁teeth ▁from ▁a ▁site ▁in ▁the ▁early ▁Bar st ov ian , ▁around ▁ 1 5 – 1 6 ▁million ▁years ▁ago , ▁of ▁Nev ada . ▁T ogether ▁with ▁other ▁species ▁from ▁scattered ▁local ities ▁in ▁the ▁United ▁States , ▁Japan , ▁and ▁Europe , ▁A pe om yo ides ▁is ▁class ified ▁in ▁the ▁sub family ▁A pe omy inae ▁of ▁the ▁ext inct ▁rod ent ▁family ▁E omy idae . ▁A pe omy ines ▁are ▁a ▁rare ▁but ▁w ides p read ▁group ▁that ▁may ▁have ▁been ▁adapted ▁to ▁a ▁relatively ▁dry ▁habitat . ▁ ▁As ▁is ▁characteristic ▁of ▁a pe omy ines , ▁A pe om yo ides ▁was ▁a ▁large ▁e omy id ▁with ▁high - c rown ed ▁che ek te eth ▁and ▁a ▁large ▁gap ▁between ▁the ▁in cis ors ▁and ▁che ek te eth . ▁Furthermore , ▁the ▁che ek te eth — pre m ol ars ▁and ▁mol ars — appro ach ▁a ▁bil oph od ont ▁pattern , ▁with ▁two ▁distinct ▁lo bes . ▁Other ▁features ▁distinguish ▁A pe om yo ides ▁from ▁other ▁a pe omy ines , ▁including ▁the ▁rect angular ▁shape ▁of ▁the ▁che ek te eth . ▁The ▁fourth ▁lower ▁prem olar ▁( p 4 ) ▁is ▁larger ▁than ▁the ▁mol ars ▁behind ▁it ▁and ▁has ▁two ▁roots , ▁while ▁the ▁lower ▁mol