How many fossilized species are there?

[Shpongle]

Just wondering if anyone has an estimate (or firm number) on the number of extinct fossil species that have been discovered so far?

I'm just curious how it compares to the million+ species that have been identified so far and the estimated millions of unidentified species.

[Risiko]

This site (http://www.dc.peachnet.edu/~pgore/geology/historical_lab/preservationlab.php) claims there are about 250,000 known species (of all kingdoms?), and I remember seeing that figure somewhere else, so I guess it's the current state of the art.

I believe there is a fair share of guesswork when determining extinct species. For instance many modern species shows great morphological differences between sexes, or between different stages during growth.

[Doubting Didymus]

What's a species?

[Jack the Bodiless]

I've seen it claimed that new dinosaur species are being discovered at the rate of one new species every six weeks on average, but I don't know what total has been reached.

[Valentine Pontifex]

Originally posted by Risiko
This site (http://www.dc.peachnet.edu/~pgore/geology/historical_lab/preservationlab.php) claims there are about 250,000 known species (of all kingdoms?), and I remember seeing that figure somewhere else, so I guess it's the current state of the art.

I believe there is a fair share of guesswork when determining extinct species. For instance many modern species shows great morphological differences between sexes, or between different stages during growth.

There is a fair amount of guess work and being arbitary to determine what is a species in the here and now as well. Of course the problems are far worse with fossils living over a range of time instead of living organisms living in a single time.

[God Fearing Atheist]

Originally posted by Jack the Bodiless
I've seen it claimed that new dinosaur species are being discovered at the rate of one new species every six weeks on average, but I don't know what total has been reached.

It would really depend on who you asked. Total species, including nomina dubia, nomina nuda, referals, synonyms, etc is well over 2300.

The number of actual species is probably half that or so.

-GFA