Re: Magnapaulia, "new" lambeosaurine from Baja California, Mexico

[tyazbeck@comcast.net]

Tsk, tsk-too much splitting. This material does not represent a new genus, at 
least from my point of view. I wish that more existing genera should be 
bolstered by adding species, rather than over-exaggerating dinosaur diversity 
by creating excess genera. This is especially common within the Ceratopsidae 
and Hadrosauridae, taxa which usually require merging that happens 
periodically. Hypacrosaurus, Corythosaurus, Lambeosaurus, might as well be part 
of a single genus, to give an example. Please correct me if I am wrong in 
saying that ceratopsians and hadrosaurs are only different mainly in cranial 
anatomy (ornamentation)...

----- Original Message -----
From: "Ben Creisler" <bcreisler@gmail.com>
To: dinosaur@usc.edu
Sent: Tuesday, June 12, 2012 5:42:13 PM
Subject: Magnapaulia, "new" lambeosaurine from Baja California, Mexico

From: Ben Creisler
bcreisler@gmail.com

New paper in PLoS ONE, creating a new genus (Magnapaulia) for
"Lambeosaurus" laticaudus. Since the gender of the new generic name is
feminine, the correct Neo-Latin combination technically should be
Magnapaulia laticauda. The specific "laticaudus" was originally formed
from the Latin latus "wide" + noun cauda "tail" and made masculine to
match the gender of Lambeosaurus....


Albert Prieto-Márquez, Luis M. Chiappe & Shantanu H. Joshi (2012)
The Lambeosaurine Dinosaur Magnapaulia laticaudus from the Late
Cretaceous of Baja California, Northwestern Mexico.
PLoS ONE 7(6): e38207.
doi:10.1371/journal.pone.0038207
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0038207



The taxonomy, osteology, phylogenetic position, and historical
biogeography of the lambeosaurine hadrosaurid Magnapaulia laticaudus
(new combination) are revised. The diagnosis of this species is
amended on the basis on two autapomorphies (i.e., longest haemal
arches of proximal caudal vertebrae being at least four times longer
than the height of their respective centra; base of prezygapophyses in
caudal vertebrae merging to form a bowl-shaped surface) and a unique
combination of characters (i.e., downturned cranioventral process of
the maxilla; tear-shaped external naris with length/width ratio
between 1.85 and 2.85; neural spines of dorsal, sacral, and proximal
caudal vertebrae being at least four times the height of their
respective centra). A maximum parsimony analysis supports a sister
taxon relationship between M. laticaudus and Velafrons coahuilensis.
Both taxa constitute a clade of southern North American
lambeosaurines, which forms a sister relationship with the diverse
clade of helmet-crested lambeosaurines from northern North America
that includes well-known genera like Corythosaurus, Lambeosaurus, and
Hypacrosaurus. According to the results of a Dispersal-Vicariance
analysis, southern North American lambeosaurines split from the
northern forms via vicariance from a common ancestor that lived in
both the northern and southern regions of the continent.