▁divers ified ▁group , ▁with ▁some ▁primitive ▁members ▁we igh ing ▁less ▁than ▁ ▁and ▁the ▁largest ▁more ▁than ▁. ▁ ▁The ▁earliest ▁and ▁most ▁primitive ▁p ant od ont s , ▁B em al ambda ▁( with ▁a ▁ ▁sk ull ▁probably ▁the ▁size ▁of ▁a ▁dog ) ▁and ▁Hy ps il ol ambda , ▁appear ▁in ▁the ▁early ▁Pale oc ene ▁Shang hu an ▁Form ation ▁in ▁China . ▁All ▁more ▁derived ▁families ▁are ▁collect ively ▁class ified ▁as ▁E up ant od ont a . ▁The ▁p ant od ont s ▁appear ▁in ▁North ▁America ▁in ▁the ▁middle ▁Pale oc ene , ▁where ▁C ory ph odon ▁surv ived ▁into ▁the ▁middle ▁E oc ene . ▁P ant od ont ▁teeth ▁have ▁been ▁found ▁in ▁South ▁America ▁( Al c ided orb ign ya ) ▁and ▁Ant arct ica , ▁and ▁foot print s ▁in ▁a ▁coal ▁mine ▁on ▁S val b ard . ▁ ▁Description ▁ ▁The ▁p ant od ont s ▁varied ▁consider ably ▁in ▁size : ▁the ▁small ▁Arch ae ol ambda , ▁of ▁which ▁there ▁is ▁a ▁complete ▁ske leton ▁from ▁the ▁Late ▁Pala e oc ene ▁of ▁China , ▁was ▁probably ▁ar b ore al , ▁while ▁the ▁North ▁American , ▁ground ▁sl oth - like ▁B ary lambda ▁was ▁massive , ▁slow - mov ing ▁(" gra vi portal ") ▁and ▁probably ▁brow sed ▁on ▁high ▁veget ation . ▁ ▁D ent ition ▁The ▁p ant od ont s ▁have ▁a ▁primitive ▁dent al