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[Fwd: identifiable growth rate]

forwarded to the list with permission
> > Hi Betty.
> >
> > This isn't directly related to the mineral-sufficiency question, nor
> > to sauropods, but it might be of interest anyhow:
> >
> > At least one of the bonebeds of the ceratopsian Pachyrhinosaurus show
> > distinct size classes.  There are five classes, ranging from "german
> > shepherd size" (I wonder whether they mean one of the smallish ones,
> > or one of the larger kind--considerable difference) to 5-m-long adult.
> > Darren Tanke and company are assuming that the clear size classes
> > indicate seasonal breeding patterns, and that classes are a year apart
> > in age.  (Makes sense to me--can't think of anything else that would
> > do it.)  Not clear whether the smallest ones are actually yearlings or
> > young-of-the-year, e.g. were the animals on the way to the breeding
> > grounds, leaving them, or anywhere in particular, when they got
> > whacked.  But at least it gives a pretty good idea of the growth
> > rates of that particular group.  (I think Lehmann said that
> > Chasmosaurus mariscalensis shows no such size classes, so it's not
> > something applicable to all the ceratopsians.)
> >
> > Pat