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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
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----- 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