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Re: Were dinosaur ecosystems continent-sized? (resend)



Hmm, I had thought that the lumping of _Anatotitan_ with _Edmontosaurus_ was 
fairly accepted; am I out of date? Has that changed again?

----- Original Message -----
From: "GUY LEAHY" <xrciseguy@q.com>
To: df9465@yahoo.co.uk, "Dinosaur Mailing List" <dinosaur@usc.edu>
Sent: Monday, April 26, 2010 12:08:42 AM GMT -06:00 US/Canada Central
Subject: RE: Were dinosaur ecosystems continent-sized? (resend)



Now that I have read the data set... :-)
 
There's one more possible error... _Albertosaurus_ listed from the Scollard.  
 
The list also suffers a bit from the usual lumper-splitter arguments; 
_Nanotyrannus_ is listed separately from _Tyrannosaurus_, while _Anatotitan_ is 
lumped with _Edmontosaurus_.
 
If one limits the comparison to Alberta/Montana/Wyoming, I would agree these 
faunas appear pretty similar, though there may be small degrees of 
provincialism.  It's a much more difficult case to extrapolate this concept to 
include New Mexico/Utah/Texas.  These dinosaur faunas are very poorly known 
relative to the northern faunas, and most of the dinosaur-bearing units in the 
southwest appear to be somewhat older than Hell Creek/Lance/Scollard taxa (the 
North Horn Fm. is an exception).  What can be said from the study of paleosols 
in the Hell Creek and North Horn is that the environments of these two units 
were significantly different, and it would not be surprising to see 
provincialism related to these differences.
 
By contrast, we can directly compare faunas of Campanian age from Alberta and 
Utah (DInosaur Park and Kaiparowits Fms.)  Both units are well constrained by 
radiometric dates, and are of similar age.  Though broadly similar in general 
appearance, at the species level, there appears to be no similarity in the 
dinosaur faunas.  As Scott Sampson writes in his book _Dinosaur Odyssey_ (page 
241):
 
"None of the sixteen dinosaur species found thus far (from the Kaiparowits) 
have been conclusively documented in the northern region of western North 
America."
 
On page 242:  "Not only is this finding inconsistent with migrations between 
the northern and southern regions of North America, but it also suggests that 
most kinds of dinosaur had remarkably diminutive species ranges, perhaps much 
smaller than those required by large-bodied mammals living today."
 
Dr. Sampson comments further on this topic on his blog:
http://scottsampson.blogspot.com/2010/04/provincial-dinosaurs.html
 
Guy Leahy
 
 
> Date: Fri, 23 Apr 2010 03:37:11 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: Were dinosaur ecosystems continent-sized? (resend)
> 
> I suppose I should also add that the Scollard fauna is included in the 
> dataset. 
> 
> The incorrect taxa include:
> 
> The Aguja sometimes being listed as Maastrichtian: I understand the reasons 
> why this is listed, but this is based on an old interpretation of its age.
> Pentaceratops in the Maastrichtian (it's late Campanian only)
> Parasaurolophus in the Maastrichtian Kaiparowits (Kaiparowits is Campanian)
> Saurolophus in the Maastrichtian of New Mexico
> Chasmosaurus is not known from the Kirtland Fm
> Monoclonius is a dubius taxon.
> 
> It highlights the problems of using a dataset from the paleobiology database 
> (not the authors fault), as this database seems to include every suggestion 
> that has been made in the literature, some from before recognition of 
> accidental mixing of faunas, publication of ash dates, stratigraphic 
> reinterpretation etc.
> 
> But like I say, removal of problem taxa probably reinforces the conclusions 
> of the authors. The recent Longrich paper almost certainly underestimates the 
> age of the unit from which their specimen derives;making comparison with some 
> of the Canadian units not exactly even. 
> 
> There is evidence for latitudinal variation in dino faunas, but it is not 
> nearly as strong as has been suggested. The reasons for this are largely fine 
> details in stratigraphic and taxonomic interpretation, which is a big part of 
> my thesis (hopefully will get to present a little bit at SVP). I think that 
> Vavrek and Larson's result is right on the money: some indication of 
> small-provincialism in limited clades, but not rampant across the board.
> 
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
> 
> 
> 
> ----- Original Message ----
> From: Denver Fowler <df9465@yahoo.co.uk>
> To: DML <dinosaur@usc.edu>
> Sent: Thu, 22 April, 2010 21:06:55
> Subject: Re: Were dinosaur ecosystems continent-sized? (resend)
> 
> If you check the datasets (sd01.xls), you'll find that faunas from Utah, New 
> Mexico, and Texas are included. However, a number of taxa have erroneous str
> tudy, since, if anything, removal of incorrect data reduces disparity between 
> northern and southern faunas.
> 
> 
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
> 
> 
> 
> ----- Original Message ----
> From: GUY LEAHY <xrciseguy@q.com>
> To: Dinosaur Mailing List <dinosaur@usc.edu>
> Sent: Thu, 22 April, 2010 19:54:21
> Subject: Were dinosaur ecosystems continent-sized? (resend)
> 
> 
> Resent, this time in plain text... :-)
> 
> According to this analysis, yes:
> 
> http://www.mcgill.ca/newsroom/news/item/?item_id=116613
> 
> http://www.pnas.org/content/early/2010/04/05/0913645107
> 
> A couple of problems right off the top:
> 
> 1. No faunas from Utah, New Mexico or Texas are included in the dataset. 
> 2. The upper Maastrichtian Scollard fauna is not included, but the 
> lower-middle Maastrichtian Horseshoe Canyon fauna is...
> 
> It's an interesting coincidence in time this appears a few days after the 
> publication of a new pachycephalosaur (_Texacephale_), where the authors 
> suggest exactly the opposite scenario: 
> http://www.sciencedaily.com/releases/2010/04/100419132406.htm
> 
> Guy Leahy 
> 
> 
> 
> 
>