Re: Taxonomic Status

["Jordan Mallon" <j_mallon@hotmail.com>]

> From: "Ivan Kwan" <t_rexkwan@hotmail.com>

> Is Chasmosaurus irvinensis (looks quite nice, but WHERE ARE THE BROW
> HORNS??) recognised as a valid species? What features are there to prevent 
> it from being recognised as being an atypical C. belli or C. russeli?

I have yet to read the paper, but I have been in contact with one of the 
authors who tells me that this is indeed a valid species.  To paraphrase, 
there are three specimens from western Canada (one of which is just a 
"posterior parietal bar") that show _C. irvinensis_ as having had an oddly 
"squared off" frill and comparatively smaller parietal fenestrae than other 
members of its genus.  I'm sure there are more distinctions that can be 
made, but that's as far as I'm willing to go without having seen the paper.

> Is Chasmosaurus canadensis still recognised or has it been officially 
> synonymised with C. belli?

It's been sunk into _C. belli_.  See:

Godfrey, S. J., and R. Holmes.  1995.  Cranial morphology and systematics of 
_Chasmosaurus_ (Dinosauria: Ceratopsidae) from the Upper Cretaceous of 
western Canada.  Journal of Vertebrate Paleontology 15: 726-742.

Regards.

-Jordan Mallon

http://www.geocities.com/paleoportfolio/

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp