Re: Aletopelta coombsi

[Nick <nick.gardner@gmail.com>]

On 6/28/06, ryan boyd clack <rclack@usc.edu> wrote:
> Is The Armored Dinosaurs by Carpender, 2001 still the best book on
> Aletopelta coombsi?  And is it's classifcation in Ankylosauridae still the best 
> current
> understanding? Hilton (in Dinosaurs and other mezozoic Reptiles of
California) double
> lists the fossil as both Ankylosauridae and Nodosauridae in the appendix.

Ford and Kirkland's description in that volume is the only
description/discussion I am aware of explicitly using Aletopelta (with
the exception of Carpenter's paper on ankylosaur phylogenetics which
lists it at the very least as a valid taxon).

I don't believe it has been included in any phylogenetic studies using
cladistics, and the lack of good cranial material (except teeth). The
only cladistic analysis that uses postcranial characters across a wide
range of taxa to my knowledge is Carpenter's which wouldn't let you
test the placement of Aletopelta given the compartmentalization method
he employs.

Alternative cladistic analyses that employ postcranial characters
typically are too small (consider Kirkland, 1998) or have other issues
(Sereno, 1999; Xu et al, 2001), and while the only other cladistic
analyses concerning ankylosaurs are limited to cranial characters
(Hill et al, 2003, Vickaryous et al, 2001, and so on).

Really it'd be great if Carpenter went back at some point to his
matrix from his paper in The Armored Dinosaurs and scored the taxa for
all of his characters, rather than employing compartmentalization. :(

Nick Gardner