 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Natural Science Forum / Biology / Paleontology / March 2006Carnivore comparisons,article link
http://news.yahoo.com/s/space/20060301/sc_space/thebiggestcarnivoredinosaurhisto ryrewritten > http://news.yahoo.com/s/space/20060301/sc_space/thebiggestcarnivoredinosaurhisto ryrewritten OK, this is really stupid. Let me count the ways. 1. The take-home message, that Spinosaurus is the largest theropod, is based on a skull only. How accurate a measure of total body size is a skull, do you think? 2. The differences among top contenders are slight, and I suspect they might be within the range of individual variation. 3. Sample sizes are small, some as small as 1, and that one fragmentary. 4. Estimates of weight are much more assumption-laden than estimates of length, and estimation error can be greater than any of the differences listed among species here. This is what the article has, by the way: Tyrannosaurus rex Length: 40-50 feet Weight: 6 tons Fear factor: teeth up to 13 inches long Lived: 65 million years ago Where: North America Giganotosaurus Length: 47 feet Weight: 8 tons Fear factor: 8-inch-long serrated teeth Lived: 95 million years ago Where: Argentina Spinosaurus Length: 55 feet Weight: 8 tons Fear factor: long, crocodile-like jaws Lived: 100 million years ago Where: Argentina, Morocco, Tunisia, Algeria scale) > 4. Estimates of weight are much more assumption-laden than estimates of > length, and estimation error can be greater than any of the differences > listed among species here. Indeed. It takes all of several seconds of googling to find weight estimates for Tyrannosaurus (easily the best-known of the critters in question) ranging as high as the 8 tonnes given for Gigantosaurus and Spinosaurus, but also ones as low as 5 tonnes. >> 4. Estimates of weight are much more assumption-laden than estimates of >> length, and estimation error can be greater than any of the differences [quoted text clipped - 4 lines] > question) ranging as high as the 8 tonnes given for Gigantosaurus and > Spinosaurus, but also ones as low as 5 tonnes. But a simple comparison of the diameter of the shine and thigh bones can give you a good idea of how much stress the limb could stand. > >> 4. Estimates of weight are much more assumption-laden than estimates of > >> length, and estimation error can be greater than any of the differences [quoted text clipped - 7 lines] > But a simple comparison of the diameter of the shine and thigh bones can > give you a good idea of how much stress the limb could stand. Well, I can't vouch for the reasonability of said estimates. That said, the pounding the legs would have to be able to take would not depend solely on the weight of the critter, but also on unknowns like how fast it was inclined to run around. There's another problem with these estimates that I mentioned in another thread about this; I'll just quote the revelant bit from my post there: "Variation in [weight] within a species would be considerable even with small differences in length. Just as a math's exercise, let's assume that all T. rex have the same build, and that the 6 tonne estimate is for a 45' (middle of the given range) critter. Then individuals at the extremes of the range, 40' and 50', would weigh in at 4.2 tonnes and and 8.2 tonnes, respectively." Perhaps coincidentally, that's pretty close to the 5-8 tonne range I found on google. >> >> 4. Estimates of weight are much more assumption-laden than estimates >> >> of [quoted text clipped - 29 lines] > Perhaps coincidentally, that's pretty close to the 5-8 tonne range I > found on google. So you are claiming that like all species they varied a lot? How shocking! ?8^) |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.