RE: Dinosaur megaherbivore turnover in Dinosaur Park Formation (Alberta)

[Bruce Woollatt <brucewoollatt@hotmail.com>]

I noticed on skimming this paper that Parasaurolophus in DPP is referred to as 
Parasaurolophus sp. Has "walkeri" been called into question as a valid species? 

Just wondering.....

> Date: Fri, 6 Jul 2012 08:48:58 -0700
> From: bcreisler@gmail.com
> To: dinosaur@usc.edu
> Subject: Dinosaur megaherbivore turnover in Dinosaur Park Formation (Alberta)
> 
> From: Ben Creisler
> bcreisler@gmail.com
> 
> A new online paper:
> 
> Jordan C. Mallon, David C. Evans, Michael J. Ryan & Jason S. Anderson (2012)
> Megaherbivorous dinosaur turnover in the Dinosaur Park Formation
> (upper Campanian) of Alberta, Canada.
> Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
> http://dx.doi.org/10.1016/j.palaeo.2012.06.024
> http://www.sciencedirect.com/science/article/pii/S0031018212003793?v=s5
> 
> 
> Ongoing research into the biostratigraphy of the upper Campanian
> Dinosaur Park Formation (DPF) of Alberta has demonstrated that
> megaherbivorous dinosaur taxa (ankylosaurs, ceratopsids, hadrosaurids)
> are not homogenously distributed throughout the unit. This has
> compelled proposals of different, informal assemblage zone schemes,
> and the hypothesis that faunal turnover was driven by environmental
> change associated with marine transgression. The current study tests
> previous zonation schemes in addition to the hypothesis of turnover
> pulses in the DPF. Clustering and ordination methods are used to
> demonstrate the existence of two broad assemblage zones within the
> DPF, each of which lasted ~ 600 Ka: a lower zone characterized by the
> presence of the ceratopsid Centrosaurus apertus and the hadrosaurids
> Corythosaurus, and an upper zone characterized by the presence of the
> ceratopsid Styracosaurus albertensis and the hadrosaurid
> Prosaurolophus maximus. These zones can be further sub-divided based
> on the distributions of rarer or shorter-lived ankylosaur, ceratopsid,
> and hadrosaurid species into ~ 300 Ka sub-zones. Canonical
> correspondence analysis is used to explore the association between the
> turnover of the megaherbivorous dinosaurs and various
> palaeoevironmental proxies. Megaherbivorous dinosaur turnover most
> closely corresponds to that of fossil palynomorphs. However, none of
> the palaeoenvironmental proxies explains dinosaur distribution better
> than a simple time gradient, suggesting that dinosaur turnover was not
> inextricably linked to environmental change as predicted by the
> turnover pulse hypothesis.