RE: Erketu ellisoni online free access

[Ken.Carpenter@dmns.org]

The paper shows exactly the reason why every paper does NOT need a cladogram. 
The data matrix has more question marks than known character states. This is a 
misuse of a valuable tool.


Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology/
Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205
 
Phone: 303-370-6392
Fax: 303-331-6492

for PDFs of some of my publications, as well as information of the Cedar 
Mountain Project: 
https://scientists.dmns.org/sites/kencarpenter/default.aspx
++++++++++++++++++

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf Of Ruben 
Guzman
Sent: Tuesday, March 21, 2006 12:44 PM
To: dinosaur@usc.edu
Subject: Erketu ellisoni online free access

Dear All,
   
  Guess what? This new article is already available at AMNH digital 
publications library:
   
  http://digitallibrary.amnh.org/dspace/bitstream/2246/5783/1/N3508.pdf
   
  Enjoy.
   
  Best regards,
   
  Ruben Guzman. 

Tim Williams <twilliams_alpha@hotmail.com> escribió:
  Andrew Farke wrote:

>The partial citation from the Nature site is Ksepka D. T.& Norell M. A.
>2006. AMNH Novitates, 3508.

The full citation is:

Ksepka D.T. and Norell M.A. (2006). _Erketu ellisoni_, a long-necked sauropod 
from Bor Guvé (Dornogov Aimag, Mongolia). American Museum Novitates 3508: 1-16.

Abstract: "The first specimen of the new sauropod _Erketu ellisoni_, from the 
Lower Cretaceous of the eastern Gobi of Dornogov, Mongolia, is described here. 
The specimen comprises a well-preserved articulated anterior cervical series, 
an articulated lower hindlimb, and a sternal plate. This sauropod displays a 
unique combination of features including low, bifid neural spines, elongate 
cervical centra, and crescent-shaped sternal plates. 
Computed tomography imaging reveals the vertebrae were extensively invaded with 
pneumatic camellae. The holotype individual of _Erketu_ was of modest mass 
relative to other neosauropods, but had an extremely elongate neck. 
Phylogenetic analysis indicates _Erketu_ is a member of the Somphospondyli and 
may belong to a more exclusive clade therein."

"Holotype: IGM 100/1803: articulated cervical series including complete first 
through fifth cervical vertebrae, partial sixth cervical vertebra, right 
sternal plate, articulated right tibia, fibula, astragalus, and calcaneum.

Etymology: _Erketu_: In Mongolian shamanistic tradition, there are 99 Tengri 
(deities). Erketu Tengri is the Mighty Tengri, a creator-god who called 
Yesugei, the father of Chingis Khan, into being. _ellisoni_: In honor of Mick 
Ellison, for his contributions to ongoing AMNH dinosaur research.

Diagnosis: Referable to Titanosauriformes based on elongate cervical vertebrae 
with camellae and referable within Titanosauriformes to Somphospondyli based on 
reduced neural arch lamination. Differentiated from all other Titanosauriformes 
in which cervical vertebrae are known by combination of extremely elongated (EI 
indices of anterior cervicals exceeding 5.0) cervical centra and bifurcate 
anterior cervical neural spines.

Type locality and horizon: Bor Guve: late Early Cretaceous. 
Stratigraphically, the beds at this locality lie below the Tsaagan Tsonch beds 
(a unit that contains _Iguanodon orientalis_) and above the Khara Khuutul beds, 
both believed to be of late Early Cretaceous age (Shuvalov, 2000). The lack of 
materials suitable for radiometric dating leaves the exact age of this locality 
uncertain."

Technically _Erketu_ is not a titanosaur, but a somphospondylian or a 
titanosauriform. Further material might show it to be a true titanosaur (see 
below). The phylogenetic analysis puts _Erketu_ in one of two
positions: the sister taxon of _Euhelopus_ or the sister taxon of Titanosauria. 
Thus, there is a potential for a monophyletic Euhelopodidae (_Erketu_ + 
_Euhelopus_). However, although both _Erketu_ and _Euhelopus_ are characterized 
by having very long necks, in _Euhelopus_ individual cervical vertebrae show 
little elongation; instead, the total number of cervical vertebrae in 
_Euhelopus_ is increased to 17. In _Erketu_, individual cervicals are very 
long, but we don't know the vertebral count for the neck.

There is more undescribed material from the type locality that may belong to 
_Erketu_, including some sauropod teeth. These teeth have cylindrical and 
unexpanded crowns, and if they prove to belong to _Erketu_ it may push this 
taxon up into the Titanosauria.

The authors also discuss the axial musculature of _Erketu_, with some neat 
comments on neural spine bifurcation. Sauropods as a group show no correlation 
between the latter character in the cervical series and the length of the neck 
relative to the body, in spite of the notion that (as the authors put it) "[A]s 
elongation of the neck increases, the functional benefits of bifurcation should 
increase concomitantly."

Cheers

Tim




                
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