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Re: [dinosaur] New ornithomimid Rativates evadens



The name is especially inventive: _Rativates_ (effectively 'foreteller
of ratites') - "alludes to the paradox of an 'ostrich mimic' that
existed before ostriches."  Indeed, ornithomimids are not so much
ratite mimics as ratites are ornithomimid-mimics - after all, the
ornithomimids came first.  Going back even further, both ornithomimids
and ratites are both shuvosaurid-mimics, since shuvosaurids acquired
the ratite-esque bodyplan first.

Curiously, although ornithomimids lost their first toe, no known
ornithomimid shows any loss of the second toe as well.  As well as the
ostrich group (struthionids), a didactyl pes is also seen in certain
stem gruoids (eogruids/geranoidids such as _Amphipelargus_ and
_Urmiornis_), which are also inferred to be highly cursorial. But
AFAIK no non-avian theropod had a completely didactyl pes - although
the troodontid _Tochisaurus_ perhaps comes closest (as reflected in
the name).



On Wed, Sep 21, 2016 at 2:28 PM, Alberta Claw <albertonykus@gmail.com> wrote:
> A new paper:
>
> B. McFeeters, M.J. Ryan, C. Schröder-Adams, and T.M. Cullen (2016)
> A new ornithomimid theropod from the Dinosaur Park Formation of Alberta,
> Canada
> Journal of Vertebrate Paleontology (advance online publication)
> DOI: 10.1080/02724634.2016.1221415
> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.tandfonline.com_doi_full_10.1080_02724634.2016.1221415&d=DQIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XQ2Ga-RywzIWkEc1XDHSHP55XSKz2pRqnf6tDe7X9KM&s=Yrw33oOXy4n_noPxLfbXuAVa2bNvInleznUV8M8dyz0&e=
>  
>
> A partial ornithomimid skeleton, ROM 1790, from the lower Dinosaur Park
> Formation (upper Campanian) of Alberta was previously referred to
> Struthiomimus altus, but lacks diagnostic characters of that species. It is
> here described as the holotype of a new species, Rativates evadens, gen. et
> sp. nov., diagnosed by the form of the maxilla-jugal contact, the reduction
> of the mid-caudal neural spines, the convex fusion of the left and right
> ischial shafts, the straight-edged distal end of the third metatarsal, and
> possibly the relatively enlarged medial condyle of the tibia. A histological
> section of the femur confirms that the type specimen is not a juvenile,
> despite its relatively small size (approximately 50% the size of large
> individuals of Struthiomimus altus). Phylogenetic analysis recovers
> Rativates as a member of a derived ornithomimid clade that includes
> Ornithomimus, Struthiomimus, and the Asian taxa Anserimimus and Qiupalong.
> Fusion of the proximal tarsals to the tibia in some ornithomimid specimens
> was observed to be more complete than previously recognized, increasing the
> suite of features that these non-avian dinosaurs share homoplastically with
> birds.