Re: how many species

[NJPharris@aol.com]

In a message dated 1/22/02 7:15:03 PM Eastern Standard Time, 
longrich@alumni.princeton.edu writes:

>   A good point. Where i live, we've got the northwest crow, 
>  raven, and the magpie; 

Hm.  Alaska?  I didn't know you were a Northwesterner!


>  FELIDAE: bobcat, cougar, jaguar, Panthera leo atrox(extinct) and 
>  Smilodon(extinct).

and lynx, ocelot, jaguarundi, _Miracinonyx_ (extinct), and perhaps tigers as 
well.


>   It might be expected that you'd have a couple of species of 
>  theropod per family running around at any given point, furthermore if 
>  you sampled over time, as ranges expanded and retreated, you might 
>  detect even more species, say three or four in deposit, even though 
>  only one or two lived there at any given time. 

I heartily agree, particularly as concerns the smaller theropods.


>  I haven't personally tried, but I suspect that sorting 
>  out, say Corvus corax, Corvus brachyrhynchos and corvus caurinus 
>  would be a real bitch. 

Indeed.  Some populations that have been assigned to the Common Raven _C. 
corax_ have recently been determined to be more closely related to the 
Chihuahuan Raven _C. cryptoleucus_.  There is much debate as to whether the 
Northwestern and American Crows (_C. caurinus_ and _C. brachyrhynchos_, 
respectively) are two species or one (the observable differences are mainly 
in body size and voice).  And the North American and Eurasian magpies have 
recently been split into separate species (_Pica hudsonia_ and _P. pica_); 
the most obvious differences are in voice and behavior.

I can only wonder how many of our extinct "species" would be easily 
resolvable into a number of distinct species if we could only observe their 
integument, coloration, behavior, voice, and other non-osteological 
characters.


>   Anyways, I'm beginning to think that if two dinosaurs come 
>  from widely separated areas and/or times, we should expect them to be 
>  different species. 

I would certainly agree with that, though it is difficult to justify erecting 
multiple species based solely on provenance.

--Nick P.