How Ankylosaurs Evolved Clubbed Tails

[suspsy]

http://phenomena.nationalgeographic.com/2015/09/03/join-the-club-how-ankylosaurs-evolved-their-formidable-tails/

Cool stuff! A great example of how evolutionary theory works: predicting transitional forms between older, clubless, flexy-tailed nodosaurids and younger, stiff-tailed, clubbed ankylosaurids. And the prediction proves true: Liaoningosaurus paradoxus and Zhongyuansaurus luoyangensis.

I'd like toys of them.

[Balaur]

Really cool! I'm always interested in the evolution of thyreophorans.

[goodlife18]

Clubless (and probably  flexible) tails still persisted in late Cretaceous Nodosaurs like Edmontonia, which lived at the same as Ankylosaurus.  I wonder how that can be explained?   

[suspsy]

Evolution doesn't occur in a straight, linear progression. It's more like a tree with branches sprouting off in all directions, and with some branches longer than others. Just because some ankylosaurs evolved clubs doesn't mean that all ankylosaurs had to. It's just like how not all sharks have evolved like the hammerhead.

[goodlife18]

Just a hypothesis but I have a feeling nodosaur evolution had something to do with their neck and shoulder spikes.  While Ankylosaurs became heavier in the rear end by developing club like tails, perhaps for nodosaurs, they became heavier in the front end by developing progressively larger neck and shoulder spikes.