STL Science Center

STL Science Center

24 October 2012

Show Up Big; Or In Big Pieces At Least

©Ezequiel Vera
The middle Cretaceous, while we have mentioned in North America the downsizing of the sauropods, was a time of great expansion in the titanosaur family. Not only did the overall family grow in number, but also in sheer size with the ballooning bellies and extending necks and tails reaching greater and greater sizes. The size of these animals leads to problems in preservation due to the bulk of the enormous bones. As such, Argentinosaurus is known from only a handful, a giant's handful, of bones including a partial femur, a tibia, and a small number of vertebrae, a few of which may or may not be articulated. How does such a massive creature not get preserved? The answer to that is a lot more common sense than it sounds like it should be. An animal that large dying of natural or predatory causes is not a one course meal. In fact, it makes much more sense that it would have taken a pack of animals to bring it down and, even if it had died of natural causes, the sheer number of predators and carrion animals that would have been attracted to such a large meal would have meant that tempers more than likely would have flared. This, in turn, would lead to scavengers, at least some of the time, taking off what portions of food they could carry and fleeing from the melee that most likely was imminent at any point and time around the remains. Toes could have been carried off, the skull dragged away, radius and ulna picked up in a gaping jaw of giant teeth, and on and on until all that was left were a few mud covered bones that not one animal noticed and dragged away. Those mud covered bones went through the fossilization process and were eventually uncovered by erosion and the good fortune of a fossil hunter named Guillermo Heredia in Argentina. That scenario could have been played out who knows how many times in the Cretaceous wilds of what is now Patagonia.

The alternative logical thought process involves a dying animal and its rotting corpse not being covered in mud prior to some sort of flash flood scattering rotting remainders and exposed bones, meaning that the remainder of the bones attributed to this individual could be either downstream, wherever that stream moved back in that time, or the bones could have been left to dry out, bleach and eventually fall apart, break, crack and be utterly destroyed by the elements and the animals roaming the plains. Who rightly knows what happened to those wonderful fragments of a bygone giant, but hopefully we will find more someday and have a whole picture of this amazing creature.

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