. ▁Little ▁is ▁known ▁about ▁the ▁mand ible ▁due ▁to ▁its ▁compression ▁during ▁foss il isation , ▁but ▁the ▁angular ▁had ▁a ▁later al ▁process ▁just ▁below ▁the ▁fac et ▁for ▁attachment ▁which , ▁along ▁with ▁the ▁long ▁art icular ▁fac et ▁en abling ▁a ▁sl iding ▁motion , ▁probably ▁allowed ▁Ch ima eras uch us ▁to ▁move ▁its ▁lower ▁j aw ▁back ▁and ▁forth ▁in ▁a ▁che wing ▁motion ▁to ▁gr ind ▁plant ▁matter . ▁The ▁absence ▁of ▁a ▁posterior ▁but tr ess ▁on ▁the ▁art icular ▁fac et ▁indicates ▁that ▁the ▁p tery go ide us ▁mus cle ▁could ▁have ▁generated ▁horizontal ▁force ▁en abling ▁this ▁che wing ▁to ▁take ▁place . ▁The ▁two ▁roughly ▁con ical ▁teeth ▁in ▁each ▁pre max illa ▁would ▁have ▁been ▁used ▁for ▁ni pping ▁off ▁plant ▁material ▁or ▁possibly ▁for ▁defence , ▁while ▁the ▁mol ar iform , ▁poly cus pid ▁teeth ▁in ▁the ▁max illa e ▁( at ▁least ▁four ▁in ▁each ) ▁could ▁have ▁ground ▁up ▁the ▁food . ▁Although ▁the ▁dent ary ▁teeth ▁are ▁not ▁known , ▁it ▁is ▁very ▁likely ▁that ▁there ▁was ▁one ▁con ical ▁pair ▁at ▁the ▁front ▁which ▁fitted ▁in ▁the ▁gap ▁between ▁pre max illa ▁and ▁max illa , ▁while ▁the ▁remainder ▁worked ▁with ▁the ▁max ill ary ▁teeth ▁to ▁gr ind , ▁indicating ▁that ▁Ch ima eras uch us ▁was ▁almost ▁certainly ▁a ▁her b iv ore . ▁ ▁Sp inal ▁column ▁ ▁Three ▁cer v ical ▁and ▁twelve ▁d ors al ▁verte bra e ▁are