Geoscience Reference
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ors began: at least in the Early Cretaceous, but more likely extending back into the
Jurassic.
Carnivorous Movements
Everything we know about nearly all large theropods points toward their carnivory:
teeth,jaws,claws,toothmarksinbones,bonesinabdominalcavities,andwithsome
ofthosebonesetchedbystomachacids,tonamejustafewitems.Still,nothingtells
us about how much meat could go through a theropod's system on a given day like
agigantic tyrannosaurid turd.Fortunately,paleontologists have notjust onebuttwo
suchmassivecoprolites.Botharecreditedtotyrannosaursbecauseofthefollowing:
co-occurrence with known tyrannosaur bones; age (Late Cretaceous); environment
(river floodplains, which tyrannosaurs may have preferred for hunting); size (extra-
long baguettes, anyone?); broken pieces of bone; and, most unexpected of all, fos-
silized muscle tissue in one coprolite. Both were found in Canada, one in Saskat-
chewanandtheotherinAlberta,eachofwhichhavebodyfossilsoftyrannosaurids,
such as Albertosaurus and Tyrannosaurus .
The first known coprolite attributed to a tyrannosaurid came out of fluvial
(river)depositsintheFrenchmanFormationofSaskatchewan.Thisformationdates
from the latest part of the Cretaceous Period, about 66 mya , just before an extra-
terrestrial object delivered some bad news to all non-avian dinosaurs. The best way
to describe this coprolite requires applying an overused word, but justified in this
instance: awesome. When found in the field, it was partly eroded, but after having
been recovered and put back together, it measured 44 cm (17 in) long, 13 to 16 cm
(5-6 in) wide, and had a minimum volume of 2.4 liters (0.6 gallons). Almost half
of it was composed of finely ground bones which were from a young ornithischian
dinosaur; this bone meal was held together by apatite.
Thepaleontologistswhowereluckyenoughtostudyit—KarenChinandthree
others—had little doubt it was a dinosaur trace fossil and related to carnivory. They
considered the possibility that it might be a regurgitalite, an enormous cough pel-
let that became fossilized. However, it was held together so well by apatite and in-
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