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Re: Gilmoreosaurus redescribed



Thank you for telling us about this Interesting paper !

I am nevertheless concerned with the taxonomic assignment of the
material described by the authors. Let's see the Systematic
Paleontology section:

1). 'Mandchusaurus' mongoliensis was originally based on a lot, from
which a right ilium is presently designated as lectotype by
Prieto-Márquez & Norell (2010)
=> Ok. The lot included seemingly the remains of at least 4 individuals

2) The diagnosis relies MOSTLY on the ilium.
=> Great. That is not so obvious considering I saw recent papers in
which the diagnosis provided includes no element of the type specimen.

3) Many elements are referred to the same species.
=> Ouch... The list includes several specimen of isolated ilia - no
problem here given the diagnosis. According to Prieto-Márquez & Norell
(2010:5), however:  "*The only evidence for association of more than
one bone to a single specimen was found in the only left radius and
ulna*". I.e.: there is *no reason* to refer elements other than the
ilia to this species. Including the so-called diagnostic manual
phalanges. It means also that *Gilmoreosaurus mongoliensis* differs
now from *Bastrosaurus johnsoni* pnly by the presence of an ischial
tuberosity on the ilium (Prieto-Márquez & Norell, 2010:36-37).

This is standard taxonomy, though... :-/

No hard feelings,
Cheers,
Jocelyn Falconnet

2010/8/25 Jay <sappororaptor@yahoo.com>:
> http://digitallibrary.amnh.org/dspace/handle/2246/6080
>
> --- On Wed, 8/25/10, Brad McFeeters <archosauromorph2@hotmail.com> wrote:
>
>> From: Brad McFeeters <archosauromorph2@hotmail.com>
>> Subject: Gilmoreosaurus redescribed
>> To: dinosaur@usc.edu
>> Date: Wednesday, August 25, 2010, 11:24 AM
>>
>> Prieto-Márquez, A. & M.A. Norell, 2010.  Anatomy and
>> Relationships of _Gilmoreosaurus mongoliensis_ (Dinosauria:
>> Hadrosauroidea) from the Late Cretaceous of Central Asia.
>>  American Museum Novitates 3694: 1-49.
>>
>> Abstract: The osteology of the hadrosauroid dinosaur
>> _Gilmoreosaurus mongoliensis_ is redescribed in detail based
>> on the disarticulated cranial and postcranial elements of at
>> least four individuals. These together constitute the
>> lectotype and hypodigm of this species. The diagnosis is
>> emended to include two autapomorphies (paddle-shaped
>> postacetabular process that is less than 70% of the length
>> of the iliac central plate and manual phalanx III-1 with
>> greatly asymmetrical distal surface) and the unique
>> combination of two iliac characters (presence of ischial
>> tuberosity and supraacetabular process with apex located
>> posterodorsal to ischial peduncle). The distinction of _G.
>> mongoliensis_ from _B. johnsoni_ is confirmed on the basis
>> of characters of the maxilla, dentition, ilium, ischium, and
>> pubis. Maximum parsimony analysis places _G. mongoliensis_
>> as a closely related outgroup to the Hadrosauridae, the
>> sister taxon to the clade composed of all hadrosauroids
>> closer to _Telmatosaurus transsylvanicus_ than to
>> _Bactrosaurus johnsoni_.