Has anyone ever tried to count up the number of individual fossils found for a particular creature with some longevity like T.Rex? I get the impression that even animals we know existed for millions of years are represented by a relatively small number of examples, and I'm hoping to develop a better appreciation for how difficult it can be to find fossils for creatures that didn't have long periods of stasis.

Hi Jeff,

There definitely has been. In fact this kind of data is used to place estimates on stratigraphic ranges (how long a species may have actually been around) as well as correcting for uneven sampling when constructing diversity curves (i.e. calculating the number of species that were around at particular times). This is the point of the Paleobiology Database, for example: http://paleodb.org

Many species are known from just a few individuals (few actual specimens), e.g. dinosaurs, but others exist in the thousands to millions. Your point about stasis is harder to answer, as you can probably guess, if stasis doesn't exist then if we sample a lineage more than once we might simply recognise two or more different species, but we can never really be sure when this is happening.

Last edited by Graeme Lloyd (5th Oct 2008 17:34:25)

And, Jeff, for dinosaurs in particular, many species and genera -- maybe even most -- are known from a single specimen.

I'd certianly go with "most" Mike, in fact I'd probably plump for "the vast majority of".

Well, all the really awesome ones, anyway -- Xenoposeidon, Sauroposeidon, "Pelorosaurus" becklesi, the as-yet-unpublished Hotel Mesa sauropod, The Sauropod Currently Known Only As X2, and so on :-)