RE: [paleo_bio_dinosaur_ontology] dinosaur skeletal anatomy

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> David Marjanovic
>
> >>
> Yes, that's ".0001%" and "million"! Most likely these words are from a
> catalogue editor and not Steve Parker (of NHM in London), but the figures
> sound to me so astoundingly absurd. Any comments?
> <<
>
> It may well be correct, although it's quite a high estimate. First if you
> include birds (har har) -- just imagine the number of species
> like *Sinornis
> santensis* that must have existed worldwide for, at least, most of the
> Cretaceous, but also the scansoriopterygids and compsognathids and
> "hypsilophodonts" and so on --, and secondly consider the sheer amount of
> time and space. Average "lifetimes" of endothermic species are below 5 Ma,
> IIRC.

Quick correction: Ma is for date (million years ago); Myr is for duration
(millions of years).

Also, quite frankly, the 2-4 Myr range is for MAMMALIAN species, not bird
species.  (The fossil record of Tertiary birds being rather spotty).
Furthermore, the danger with "typical species ranges" cross-taxa is that
different communities of workers might have radically different species
concepts.

Ultimately, though, the number on the book seems to have been pulled out of
thin air.  Yes, we have only a tiny fraction of the known species, but we
don't have a good grasp of the number of unknowns.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796