The 'Duckbill' Stomp

By the late Zdenek Burian. In the public domain - I think?

Modified from the original posted on the Archosaurophilia Tumblr on July 15, 2014.

Nothing tickles me more when I leaf through old dinosaur books than wimpy, gangly hadrosaurs baring their necks for a tyrannosaur's waiting jaws, seemingly without a fight. I guess it's easy to mistake them for easy prey, being that they generally lack obvious weapons of self-defense, like the flashy horns, armor, or spikes of some of their fellow ornithischians. The fact that size in and of itself can be a means of defense seems to be ill-appreciated. The largest of hadrosaurs were beefy creatures indeed - for example, Shantungosaurus from the Campanian of China, which measured up to as much as 16.6 meters in length (54 feet), larger than any theropod and doubtlessly much heavier.

Figure from the Magnapaulia description paper, Prieto-Márquez et al. (2012). Retrieved via Wikimedia Commons.

Magnapaulia laticaudus (née "Lambeosaurus" laticaudus) is another such colossal hadrosaur (though if we use D&D's metric, it's more accurately Gargantuan) from the Campanian of northern Mexico, around 73 Ma. Its most unique physical feature was surely its unusually deep tail profile, lending to its image as that of a very impressive animal indeed—it measured in somewhere between 12.5 and 16.5 meters in length (41 to 54 feet) and may have weighed in excess of 20 metric tons (22 short tons). Size alone would have been an adequate defense for something like Magnapaulia—given the opportunity, it could well have just trampled a large theropod to death. It also seems to have sported a series of large, irregular scales which may represent some kind of osteoderms, offering it a thick hide as well.

Magnapaulia's sister taxon Velafrons and an indeterminate saurolophine from the same general region also represent atypically large hadrosaurs, but the reason for this abnormal size is, as of yet, unclear. Whatever the case, far from being a land of noodly, amphibious 'duck-bills', the Baja in the Upper Cretaceous must have been a tyrannosaur's nightmare.

"Edmontosaurus pounding Albertosaurus" by Durbed. Retrieved via Wikimedia Commons.