Scientists might now be one step closer to realize how one of nature ’s most formidable weapons evolve .
The ankylosaurus were herbivorous , armour - plated dinosaur which first come out around 156 to 152 million years ago and spread out to every continent but Africa . One advanced subgroup known as theankylosauridsupped the ante with an extra defense mechanism . At the last of their tails , most specie had a mammoth club . weigh up to 45 pounds or more , these bludgeoning tool could have been swung with unbelievable — perhaps even bone - shattering — force .
Anew newspaper publisher , published inJournal of Anatomy , argues that the creatures ’ unfaltering prat pre - date these powerful clubs . As cobalt - source Victoria Arbour guide out , “ In order for an ankylosaur to patronage the weight of a knob and swing it efficaciously , the butt needs to be stiff , like an axe handle … otherwise , the momentum generated by the knob ’s weight could buck sinew or dislocate vertebra . ”
So , which came first , the unbending hind end or the heavy club ? Or did they appear simultaneously ? To try all three scenarios , Arbour and fellow paleontologist Phillip J. Currie search over several million year ’ worth of ankylosaur phylogeny , comparing and contrast such animal as China’sGobisaurusand theclub - lessLianoningosaurus .
They observed that while stiff - tailed ankylosaurids arrived during the early Cretaceous Period ( 145 to 100 million years ago ) , club species did n’t make their launching until much later on . So — to re - utilize Arbour ’s “ axe ” analogy — it looks like the handle raven the brand . “ While it ’s potential that some of the specie could still have make grow … [ both ] in tandem , ” she say , “ it seems most potential that the shadow stiffen prior to the growing of the … knob , so as to maximize the tail ’s effectiveness as a weapon . ”
Club - less mintage had other means of protection . Certain metal money — like North America’sSauropelta — came with lethal - looking shoulder spikes . Also , stoutGastoniahad shark tail fin - shaped blades run down its fundament .
Virtually all ankylosaur have been described as “ armoured combat vehicle - comparable ” in appearance . That ’s because bony scale squall osteoderms covered much of their skin , rendering it all but dense . With predators likeT. rexaround , such extreme measure were utterly necessary .
