Albinykus, new Mongolian alvarezsaurid in Jan. JVP

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

The January 2011 Journal of Vertebrate Paleontology is 
now available online at:
http://www.informaworld.com/smpp/title~db=all~content=g933
279051~tab=toc

There's a batch of dinosaur-related articles, including a 
new theropod:

Sterling J. Nesbitt; Julia A. Clarke; Alan H. Turner; 
Mark A. Norell (2011) 
A small alvarezsaurid from the eastern Gobi Desert offers 
insight into evolutionary patterns in the 
Alvarezsauroidea. 
DOI: 10.1080/02724634.2011.540053 
Journal of Vertebrate Paleontology, Volume 31, Issue 1 
January 2011 , pages 144 - 153 
http://www.informaworld.com/smpp/content~db=all~content=a9
33251736~frm=titlelink

Abstract 

A partial postcranial skeleton of a small alvarezsaurid 
from the Late Cretaceous of the Mongolian eastern Gobi 
Desert locality of Khugenetslavkant represents the first 
reported articulated theropod material from that 
locality. The specimen is recognized as the holotype of a 
new taxon herein named Albinykus baatar, gen. et sp. nov. 
Phylogenetic analysis places Albinykus within 
Alvarezsauridae as the sister taxon of Shuvuuia, another 
Late Cretaceous Mongolian taxon from the slightly younger 
Djadokhta Formation. The complete coossification of the 
proximal tarsals with the tibia, and of the distal 
tarsals and proximal metatarsals, present in Albinykus 
are previously unknown in Alvarezsauridae. Extensive 
fusion is consistent with histological data from the 
tibia indicating that the individual was a subadult. 
These results are striking given that Albinykus is among 
the smallest known non-avian dinosaurs with a body mass 
no greater than 1 kg and ranks among the smallest known 
alvarezsaurids. Alvarezsauridae shows a decreasing size 
trend throughout its evolutionary history, a rarity among 
dinosaurian clades. Within maniraptoran dinosaurs, such a 
trend has thus far only been recognized within Avialae 
and at the origin of Paraves with respect to other 
coelurosaurs. The holotype was recovered articulated in 
a 'seated' position, with hind limbs aligned and the feet 
tucked under the body. This body posture, which is 
present in Aves, has been previously noted in other 
maniraptoran clades (i.e., Oviraptoridae Troodontidae) 
and is now recognized in Alvarezsauridae.