In discussions about Scanella and Horner's "Toroceratops" theory, there is one objection that will inevivably pop up, "But Torosaurus was smaller than Triceratops." Here I intend to adress that issue. This statement seems to stem from the measurements found in most of the old dinosaur books (and some more recent ones). In them, Triceratops is listed as being 30 feet long, while Torosaurus is said to be 25 feet. However, there is an important problem with the measurements for the latter; no complete Torosaurus skeletons have been found. Without a complete skeleton, exact measurements are impossible to take, so one has to estimate the size of an animal. That's what the sizes listed in these books are, estimates. We really do not know exactly how large Torosaurus (whether you think it's a distinct genus or a mature Triceratops) really got. So, regardless of your position in this debate, size is not a valid argument.
It is also important to remember not to take measurements in books too much to heart. In addition to some being estimates from incomplete material, size can be highly variable among individuals within a species. Even when we do have good, complete skeletons to measure, the sizes listed are still either the average or maximum length, and does not constitute every single individual. Keep that in mind during discussions regarding size.
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Good post. I was wondering about this size issue.
ReplyDeleteGood post, this crops up much too often in discussions relating to this issue.
ReplyDeleteIt may be worthy to note that in the newest version of Holtz's genus list, Torosaurus is now listed as being the same size as Triceratops: http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2010.pdf