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Re: Fastovsky vs Archibald
Yikes, I mis-typed my point.
I was trying to challenge Tim Donovan's suggestion that some Hell Creek
dinosaurs may have gone extinct before K-T boundary. Tim specifically
referred to two genera (Edmontonia and (?)Hypacrosaurus).
Yes, a lot of extinction studies have been conducted in the Hell Creek
Fm. All of it, to my knowledge, looking at the issue as a "big picture"
story. I have misplaced my copy of Lilligraven and Eberle's paper. What
did the authors have to say specifically about (?)Hypacrosaurus and
The Lance Fm. may provide a better test of Edmontonia's purported
premature extinction, because the evidence for this hypothesis is pretty
ambiguous in the Hell Creek Fm.
On Mon, 20 Jun 2005 08:51:32 -0400 "Thomas R. Holtz, Jr."
> > From: firstname.lastname@example.org [mailto:email@example.com]On
> Behalf Of
> > Phil Bigelow
> > One point that should be emphasized is that no one (to my
> knowledge) has
> > actually conducted a rigorous (e.g., non-anecdotal)
> > study of intraformational extinctions within the Hell Creek
> Lillegraven, J.A. & J.J. Eberle. 1999. Vertebrate faunal changes
> through Lancian and Puercan time in southern Wyoming. Journal of
> Paleontology 73:691-710.
> We summarize faunal changes through the thickest and one of the most
> complete records of terrestrial vertebrates spanning Lancian
> ( approximately latest Cretaceous) and Puercan ( approximately
> earliest Paleocene) ages, the type Ferris Formation in the Hanna
> Basin, southern Wyoming. Observed faunal changes predate tectonic
> definition of local Laramide basins. Nonmammalian vetebrates
> exhibit no major changes in taxonomic composition below the
> Lancian-Puercan boundary; diversity of non-avian dinosaurs remains
> within uppermost levels of the Lancian section. Nevertheless,
> dinosaurian extinction was not necessarily "catastrophic" within a
> biologically relevant interval. Primitive condylarths appear locally
> above the highest known dinosaurs, probably as immigrants. At
> least in this part of the North American western interior, the first
> evolutionary radiation of condylarths was subsequent to the
> last appearance of dinosaurs, not synchronous with or prior to it.
> Niche-partitioning among condylarths is first recorded near the
> boundary between Puercan Interval-zones Pu1 and Pu2 (early and
> middle Puercan time, respectively), by which time the first great
> mammalian diversification of the Cenozoic had begun. Major
> experimentations in dental morphology and increasing ranges of body
> had developed within 400,000 years of the Lancian-Puercan boundary.
> We recognize no evidence suggesting that placental mammals were
> "recovering" from events that led to demise of the dinosaurs. The
> true diversity of marsupials and condylarths precisely at the
> Cretaceous-Tertiary boundary, throughout the western interior,
> remains unknown. We cannot, therefore, evaluate extensiveness of
> competition, if any, at that time among members of the two groups.
> Reviewed breifly on DML: http://dml.cmnh.org/2000Mar/msg00634.html
> Thomas R. Holtz, Jr.
> Vertebrate Paleontologist
> Department of Geology Director, Earth, Life & Time
> University of Maryland College Park Scholars
> Mailing Address:
> Building 237, Room 1117
> College Park, MD 20742
> Phone: 301-405-4084 Email: firstname.lastname@example.org
> Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796