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RE: Leptorhynchos, new caenagnathid theropod from Late Cretaceous of North America



They do test this: Leptorhynchos emerges as a caenagnathine, and Elmisaurus as 
a non-caenagnathine caenagnathid.  (There is an unfortunate error in the 
phylogenetic definition of Caenagnathinae sensu Longrich et al. 2013: they 
define it as "the clade including all species closer to Caenagnathus collinsi 
than either Caenagnathasia martinsoni or Elmisaurus elegans," but it is obvious 
from context that they actually meant E. *rarus* here.)

Surprisingly there is no comment on Ojoraptorsaurus, the other recently named 
southern caenagnathid.




> Date: Tue, 23 Apr 2013 19:41:20 -0700
> From: mickey_mortimer111@msn.com
> To: dinosaur@usc.edu
> Subject: RE: Leptorhynchos, new caenagnathid theropod from Late Cretaceous of 
> North America
> 
> I'll be interested to see if Leptorhynchos emerges somewhere besides sister 
> to Elmisaurus rarus, so that the new genus for elegans was justified.  The 
> trend lately has been to ignore E. rarus as somehow not oviraptorosaurian.  
> Also note the abstract accidentally lists the combination Chirostenotes 
> gaddisi.
> 
> Mickey Mortimer
> 
> ----------------------------------------
> > Date: Tue, 23 Apr 2013 19:37:03 -0700
> > From: bcreisler@gmail.com
> > To: dinosaur@usc.edu
> > Subject: Leptorhynchos, new caenagnathid theropod from Late Cretaceous of 
> > North America
> >
> > From: Ben Creisler
> > bcreisler@gmail.com
> >
> >
> > A new paper with a new genus of theropod:
> >
> >
> > Nicholas R. Longrich, Ken Barnes , Scott Clark , and Larry Millar (2013)
> > Caenagnathidae from the Upper Campanian Aguja Formation of West Texas,
> > and a Revision of the Caenagnathinae.
> > Bulletin of the Peabody Museum of Natural History 54(1):23-49
> > doi: http://dx.doi.org/10.3374/014.054.0102
> > http://www.bioone.org/doi/abs/10.3374/014.054.0102
> >
> > Caenagnathid theropods are a relatively common part of the theropod
> > fauna in the Late Cretaceous of Asia and North America, but have not
> > previously been described from the southernmost United States. Here,
> > we describe caenagnathid fossils from 
> > Formation of West Texas, and revise the systematics of caenagnathids
> > from the Campanian of North America. Caenagnathids from the late
> > Campanian of Canada represent three species in three genera:
> > Caenagnathus collinsi, Chirostenotes pergracilis and Leptorhynchos
> > elegans gen. nov. Leptorhynchos is diagnosed by its small size, its
> > short, deep mandible, and the upturned tip of the beak. A single
> > caenagnathid is known from the late Campanian of Utah, Hagryphus
> > giganteus. Two caenagnathid species occur in the Aguja Formation,
> > ?Chirostenotes sp. and Leptorhynchos gaddisi sp. nov. L. gaddisi
> > differs from L. elegans in that the tip of the beak is narrower and
> > less upturned. Phylogenetic analysis recovers Caenagnathidae and
> > Oviraptoridae as monophyl
> 
> > North American species seem to form a monophyletic assemblage, the
> > Caenagnathinae, within which Chirostenotes and Caenagnathus form a
> > clade to the exclusion of Leptorhynchos. The discovery of
> > Chirostenotes gaddisi provides more evidence for the existence of a
> > distinct dinosaurian fauna in southern North America during the
> > Campanian. Furthermore, the Aguja fossils show that caenagnathids were
> > widespread and highly diverse in the Late Cretaceous of North America.
> > This diversity was maintained in two ways. First, variation in body
> > size and beak shape suggests that diversity within formations is
> > maintained by niche partitioning, in a way analogous to Darwin's
> > finches. Second, diversity is maintained by high degree of endemism,
> > with different species of caenagnathids occurring in different
> > habitats.