RE: Number of valid dinosaur genera

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

Give me a couple of weeks; I'm updating my database... :-)

That said, a "genus" is an artificial idea. So whether we regard Anatosaurus 
annectens and Edmontosaurus regalis as separate genera
or simply call them Edmontosaurus annectens and Edmontosaurus regalis, we 
really are recognizing precisely the same amount of
biological diversity.

As for your second question: depends on the taxonomy used. However, dinosaur 
paleontologists are notorious (even among vertebrate
paleontologists!) for oversplitting species into their own genera. So people 
who work in many other discplines would easily put all
the pachyrostran centrosaurines as simply species in Pachyrhinosaurus, all the 
tyrannosaurines into Tyrannosaurus, etc.

And Psittacosaurus has the highest number of generally accepted species within 
non-avian dinosaurs at present, but that simply means
no one has gone in and split them out into two or more genera... :-S

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA

> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> dinosaurtom2015@seznam.cz
> Sent: Friday, January 09, 2015 8:19 AM
> To: dinosaur@usc.edu
> Subject: Number of valid dinosaur genera
> 
> Good day!
> 
> I would like to ask, if there is any comprehensive, up-to-date database of 
> all valid dinosar genera, known today (as of January
2015). I
> seem to recall there was about 800 scientifically/taxonomically valid genera 
> and just over
> 1000 species alltogether. Does anyone run some kind of database from which 
> one can directly obtain statistics like how many
dinosaur
> genera are known per stage/period, how many saurischians v. ornithischians, 
> how many per country/continent etc?
> 
> Also, how many dinosaur genera include more than one species? I know that _ 
> Psittacosaurus_ is e "record holder" with about 10
> species, but what about the second and third place? And finally - is there 
> any indication, that _ Tyrannosaurus_ had more than one
> species (i. e. "rex") when we take into account that it lived about 2-3 
> million years on an area spanning from Canada to New
Mexico?
> Thank you very much, Tom