Re: [dinosaur] Non-avian dinosaur biodiversity

Greetings,

You need to define your parameters? Do you mean "at any given time" or "across the whole of the Mesozoic"?

In the present day we have 6400 species of mammals. Removing Chiroptera and Rodentia (neither of which are comparable to non-avian dinosaurs), that's aboutÂ2500 species of livingÂmammal broadly equivalent to non-avian dinosaurs. Let's add back some for the late Pleistocene megafaunal extinctions and say roughlyÂ3000.Â

So an approximation of standing diversity of mammals is 3000 species broadly comparable to non-avian dinosaurs at any given moment.

You'd then have to approximate the average duration of a species, and then calculate that over the whole of the Mesozoic.

But, complications:

Â* Large dinosaurs have a MUCH larger size range from birth to adulthood than do large placental mammals, and so any one species of larger dinosaur probably represents multiple species of mammal with regards to niche space (as argued by Michael Brett-Surman and various researchers ever since.)

* Changing position of continents, seaways, and climate zones may promote provinicialization or cosmopolitanism at any given time slice. In a world where species could have extensive realized ranges, you might have fewer species overall than those where geographic barriers are numerous.

So TL;DR, we don't really know.

On Fri, Aug 14, 2020 at 3:49 AM Poekilopleuron <dinosaurtom2015@seznam.cz> wrote:

Good day to all listmembers! I wonder, what was the true biodiversity of non-avian dinosaurs during the Mesozoic? I am aware of some estimates of the number of taxa ranging from 1000 to about 6000 species, but it seems far too small a number to me. Personally I would have guesstimate on the order of tens of thousands species, perhaps even more. At least that is what research in microsites, Burmese amber etc. suggests. Any opinions? Thank you in advance! Tom

Thomas R. Holtz, Jr.
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