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Re: dracrorex and National Geographic
Does anyone have a PDF of the Horner paper mentioned here?
On Mon, 26 Nov 2007, Denver Fowler wrote:
> I just saw this month's National Geographic magazine. Isn't it a tad
> embarrassing to see "Dracorex hogswartsia" on the cover, and in the article?:
> when "Dracorex" was recently outed (along with "Stygiomoloch") as growth
> stages of Pachycephalosaurus (Horner et al, SVP2007): not even mentioned in
> the article. I find it pretty surprising that National Geographic would sit
> so behind the times like this.
> Denver Fowler
> Fieldwork pictures NM 2002-4 & China 06:
> TV Work:
> ----- Original Message ----
> From: Sarah Werning <email@example.com>
> To: firstname.lastname@example.org; email@example.com
> Sent: Monday, 26 November, 2007 2:29:33 PM
> Subject: Re: Marsupial forelimbs... or rather hindlimbs
> Well, it'll be nice to see this paper when it comes out. Obviously, to
> speak about a heterochrony you need to compare ontogenies across
> phylogeny, and though there are studies that have looked at this
> question (and similar ones) for these groups, this is certainly the
> largest placental-marsupial developmental comparison to date.
> I don't know that this is especially novel in terms of thinking,
> though; there are papers that have suggested deceleration of hindlimbs
> is what is going on in marsupials (although the majority do suggest it
> is acceleration of forelimbs). It will be interesting to see their
> methods: do they hold timing of development of hindlimbs constant
> relative to a third event, such as brain development? Or constant to
> time/developmental stage? A lot of the current literature holds brain
> development constant and compares limb or facial development relative
> to that. I'm especially curious about which outgroups they used and
> what's going on in them.
> In terms of comparing forelimb to brain development, there is a large
> body of literature that suggests that marsupials are indeed developing
> their forelimbs earlier than placentals in both absolute and relative
> terms. In several cases (e.g., Monodelphis, Dasyurus) you get
> development and ossification of the facial and forelimb bones (and
> significant development of their associated muscles) while the brain
> is still undifferentiated neuroepithelium (and while big chunks of the
> rest of the body is undifferentiated mesenchyme). The
> forelimb-hindlimb timing is interesting, but think the story with the
> timing of brain/braincase and limbs is more interesting.
> For some really cool research by someone who completely gets
> heterochrony, and who works on limb and craniofacial development in
> marsupials and placentals, check out Kathleen K Smith's website:
> Most of her papers are available as free pdf's.
Bainbridge Island, WA, USA
"Rallidae all the way!"