▁number ▁may ▁vary , ▁even ▁within ▁species . ▁The ▁cer v ical ▁verte bra e ▁of ▁A pat osa urus ▁and ▁Br ont osa urus ▁are ▁st outer ▁and ▁more ▁robust ▁than ▁those ▁of ▁other ▁di pl od oc ids ▁and ▁were ▁found ▁to ▁be ▁most ▁similar ▁to ▁Cam ar as aur us ▁by ▁Charles ▁Whit ney ▁Gil more . ▁In ▁addition , ▁they ▁support ▁cer v ical ▁rib s ▁that ▁extend ▁farther ▁towards ▁the ▁ground ▁than ▁in ▁di pl od oc ines , ▁and ▁have ▁verte bra e ▁and ▁rib s ▁that ▁are ▁nar ro wer ▁towards ▁the ▁top ▁of ▁the ▁neck , ▁making ▁the ▁neck ▁nearly ▁tri angular ▁in ▁cross - section . ▁In ▁A pat osa urus ▁l ou is ae , ▁the ▁at las - axis ▁complex ▁of ▁the ▁first ▁cer v ical s ▁is ▁nearly ▁f used . ▁The ▁d ors al ▁rib s ▁are ▁not ▁f used ▁or ▁tight ly ▁attached ▁to ▁their ▁verte bra e ▁and ▁are ▁instead ▁lo os ely ▁art ic ulated . ▁A pat osa urus ▁has ▁ten ▁d ors al ▁rib s ▁on ▁either ▁side ▁of ▁the ▁body . ▁The ▁large ▁neck ▁was ▁filled ▁with ▁an ▁extensive ▁system ▁of ▁weight - s aving ▁air ▁sac s . ▁A pat osa urus , ▁like ▁its ▁close ▁relative ▁Sup ers aur us , ▁has ▁tall ▁neural ▁sp ines , ▁which ▁make ▁up ▁more ▁than ▁half ▁the ▁height ▁of ▁the ▁individual ▁b ones ▁of ▁its ▁verte bra e . ▁The ▁shape ▁of ▁the ▁tail ▁is