Playin' Yer Banji

[Jaime Headden <qi_leong@hotmail.com>]

Under the radar, a new oviraptorosaur:

Xu X. & Han F.-l. 2010. A new oviraptorid dinosaur
(Theropoda: Oviraptorosauria) from the Upper Cretaceous of China.
_Vertebrata PalAsiatica_ 48(1):11-18.

Abstract:

  "Here we report a new oviraptorid taxon based on a specimen possibly 
collected from the Upper Cretaceous Nanxiong Formation of Ganzhou, Jiangxi, 
China. This new taxon is distinguishable from other species based on the 
following features: a crest formed by the premaxillae and nasals having a 
stepwise posterior end and bearing two longitudinal grooves and numerous 
oblique striations on each of its lateral surfaces, an extremely elongate 
external naris that is posteriorly situated and close to the orbit, a deep 
fossa on the dorsal surface of the palatal ramus of the pterygoid, several 
longitudinal grooves along the posterior part of the dorsal margin of the 
dentary, and several tubercles along the lateral shelf at the dorsal margin of 
the surangular. This new taxon possesses some palatal and mandibular features 
not seen in other oviraptorids but similar to those in more basal 
oviraptorosaurs, suggesting a relatively basal position for this taxon within 
the Oviraptoridae. This systematic hypothesis is supported by a numerical 
cladistic analysis. This discovery not only adds to the known diversity of Late 
Cretaceous oviraptorids, but provides significant new information on the 
evolution of some oviraptorid features."

  Names *Banji long*, from a nearly complete immature skull and mandible (IVPP 
V16896). Etymology refers to the striations (ban) on the nasopremaxillary crest 
(ji), and translates as "striated crested dragon."

  The locality of the material is unknown, as it was collected privately from 
what is purportedly the Hongcheng Basin of Naxiong, which is generally 
correlated with the Nanxiong Formation (uppermost Upper Cretaceous) near 
Ganzhou, Jianxi Province.

  The specimen is tiny, less than 7cm long, yet preserves a crest (and will 
help argue that crested vs crestless specimens do not resolve age-based 
separation of taxa). *B. long* is diagnosed by the presence of a crest with a 
distinct caudal "step" (compare to *Kritosaurus* and *Gryposaurus*) with 
striations on it, an extremely large external narial fenestra, a fossa on the 
dorsal surface of the palatal process (anterior ramus) of the pterygoid, and 
various ornamental grooves and tubercles on the surangular/angular complex of 
the mandible.

  Xu and Han presented a cladogram that results from an analysis produced by Xu 
et al (2007: _Nature_ 447, the *Gigantoraptor* paper, which derives from the 
Osmolska et al. work of 2004, and added the current taxon and *Nemegtomaia*. 
Two trees produce a topology where the extremely oviraptorid-like and rounded 
skull is one of the most basal oviraptorids, excluding *Gigantoraptor*. This is 
largely due to the extremely large external mandibular fenestra, and the very 
plesiomorphic structure of the palate, including an elongated palatine, 
partially verticalized ectopterygoid, and a vomer which is lower than it is in 
oviraptorids (where it forms a vertical plate and is dorsal to the premaxillary 
and maxillary palatal processes). All other features are similar to other 
minute oviraptorids, such as *Conchoraptor*.

Cheers,

  Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


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Backs)

                                          
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