▁the ▁animal ▁in ▁question , ▁show ▁where ▁there ▁would ▁be ▁mus cle ▁layer ing , ▁locate ▁the ▁mus cles ▁and ▁joint s , ▁and ▁finally ▁find ▁the ▁mus cle ▁properties ▁before ▁finding ▁the ▁g ait ▁and ▁speed . ▁The ▁results ▁of ▁the ▁bi ome chan ics ▁study ▁revealed ▁that ▁Argent in osa urus ▁was ▁mechan ically ▁compet ent ▁at ▁a ▁top ▁speed ▁of ▁ 2   m / s ▁( 5   m ph ) ▁given ▁the ▁great ▁weight ▁of ▁the ▁animal ▁and ▁the ▁stra in ▁that ▁its ▁joint s ▁were ▁capable ▁of ▁bearing . ▁ ▁The ▁results ▁further ▁revealed ▁that ▁much ▁larger ▁terrest rial ▁verte br ates ▁might ▁be ▁possible , ▁but ▁would ▁require ▁significant ▁body ▁rem od eling ▁and ▁possible ▁sufficient ▁behavior al ▁change ▁to ▁prevent ▁joint ▁collapse . ▁ ▁Body ▁size ▁ ▁Sau rop ods ▁were ▁gig antic ▁descend ants ▁of ▁surprising ly ▁small ▁ancest ors . ▁Bas al ▁din osa ur iformes , ▁such ▁as ▁Pseud ol ag os uch us ▁and ▁Mar as uch us ▁from ▁the ▁Middle ▁Tri ass ic ▁of ▁Argentina , ▁we ighed ▁approximately ▁ ▁or ▁less . ▁These ▁evol ved ▁into ▁sa ur isch ia , ▁which ▁saw ▁a ▁rapid ▁increase ▁of ▁b au plan ▁size , ▁although ▁more ▁primitive ▁members ▁like ▁E or apt or , ▁Pan ph ag ia , ▁P ant yd rac o , ▁Sat urn alia ▁and ▁Gu a ib as aur us ▁still ▁retained ▁a ▁moder ate ▁size , ▁possibly ▁under ▁. ▁Even ▁with ▁these ▁small , ▁primitive