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Condorraptor and Middle Jurassic Avialans



Two new papers that haven't been mentioned here yet-

Rauhut, 2005. Osteology and relationships of a new theropod dinosaur from
the Middle Jurassic of Patagonia. Palaeontology. 48(1), 87-110.

Abstract- A new taxon of theropod dinosaur is described as Condorraptor
currumili gen. et sp. nov., from the Middle Jurassic (Callovian) Cañadón
Asfalto Formation of Chubut Province, Argentinean Patagonia. The taxon is
represented by a single fragmentary postcranial skeleton. Although
incompletely known, Condorraptor is the second most complete theropod from
the Middle Jurassic of Gondwana. The new taxon is characterized by the
absence of a posterior incision between the fibular condyle and the medial
side of the proximal articular end of the tibia, the pleurocoels in the
anterior cervicals being situated posteroventral to the parapophyses, and
the presence of a pronounced 'step' between the distal articular facet and
shaft of Mt IV. Pneumatic features of the vertebral column show strong
variation between the left and right side. Condorraptor gen. nov. can be
referred to the Tetanurae and is a representative of a global radiation of
basal tetanurans in the Early to Mid Jurassic.

Rauhut originally mentioned this taxon at SVP 2002-
http://dml.cmnh.org/2002Oct/msg00326.html .  I've previously noted the
absence of posterior tibial incisions in "Allosaurus" tendagurensis,
seemingly a tetanurine due to the distally placed fibular crest.  As I note
in the SVP details page, it may be related.  Rauhut presents no explicit
phylogeny in the published paper, merely saying Condorraptor is a tetanurine
more basal than Spinosauroidea and Avetheropoda, in the same grade as
"Szechuanoraptor" and Xuanhanosaurus.  Pdf's are available.

Also of interest-

Rasnitsyn and Zhang, 2004. Composition and age of the Daohugou hymenopteran
(Insecta, Hymenoptera = Vespida) assemblage from Inner Mongolia, China.
Palaeontology. 47(6), 1507-1517.

The authors provisionally conclude the Daohugou Formation is Middle
Jurassic, based on comparisons with other hymenopteran faunas.  This is
where the Epidendrosaurus holotype was found, if you recall.  Middle
Jurassic avialans are looking more probable.

"Based on the above evidence one can conclude that the composition of the
Daohugou assemblage is
intermediate between the early Late Jurassic assemblage of Karatau and
assemblages from near the Lower/
Middle Jurassic boundary. This implies that the Daohugou assemblage is
probably older than the Karatau
assemblage and of Mid Jurassic age. However, this inference should be
considered as preliminary because
current understanding of the fossil history of hymenopterans is poor,
particularly in light of the absence of
rich and well-dated Middle Jurassic hymenopteran assemblages. Only direct
comparison with rich,
well-dated hymenopteran assemblages will preclude the possibility that the
archaic appearance of the
Daohugou assemblage is a function of palaeogeography or palaeoecology, as is
the case for contemporary
hymenopteran biotas of Australia and New Zealand."

Also in volume 48(1) are papers on Ichthyostega taxonomy, Endennasaurus,
Yarasuchus (a new prestosuchid) and another new dinosaurian taxon Jaime will
comment on.

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html