, ▁while ▁Arist on ect es ▁and ▁K ai w he ke a ▁represent ▁a ▁later ▁C ret ace ous ▁radiation ▁from ▁G ond w ana . ▁ ▁App earance ▁ ▁Arist on ect idae ▁were ▁character ized ▁by ▁a ▁relatively ▁larger ▁head ▁and ▁shorter ▁neck ▁than ▁the ▁P les ios aur idae ▁and ▁El asm osa ur idae . ▁Te eth ▁res emble ▁those ▁of ▁the ▁P les ios aur idae . ▁The ▁group ▁is ▁known ▁only ▁from ▁sc ant y ▁and ▁fragment ary ▁remains . ▁ ▁The ▁formal ▁diagn osis ▁of ▁the ▁cla de ▁is ▁that ▁they ▁possess : ▁ ▁A ▁sn out ▁that ▁is ▁relatively ▁long ▁but ▁un con str icted ▁and ▁wide ▁anterior ly ▁ ▁A ▁par oc cip ital ▁process ▁of ▁the ▁op is th otic ▁that ▁art icul ates ▁only ▁with ▁the ▁squ amos al ▁ ▁Te eth ▁that ▁are ▁small ▁and ▁relatively ▁narrow ▁( c rown ▁length ▁< ▁ 1   cm ) ▁ ▁Number ▁of ▁pre max ill ary ▁teeth ▁is ▁ 7 ▁or ▁more ▁ ▁Number ▁of ▁max ill ary ▁teeth ▁is ▁greater ▁than ▁ 3 0 ▁ ▁Pal ate ▁with ▁a ▁vent r ally ▁expanded ▁b oss ▁project ing ▁out ▁of ▁the ▁plane ▁of ▁the ▁pal ate ▁between ▁the ▁posterior ▁and ▁anterior ▁inter p tery go id ▁vac u ity ▁ ▁Number ▁of ▁cer v ical ▁verte bra e ▁greater ▁than ▁ 3 2 ▁ ▁C erv ical ▁verte bra e ▁much ▁wider ▁than ▁long ▁ ▁C erv ical ▁verte bra e ▁with