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Phil Bigelow wrote-
> Sankey (2003), in a meeting abstract, noted in passing that theropod teeth
> previously assigned to Paronychodon have been reassigned to Richardoestesia
> Who is the author (full citation, if possible) of this re-assignment?
Sankey (2002) has suggested Paronychodon and Richardoestesia teeth are
morphotypes of the same taxon, based on morphology and relative abundance. The
details of this study have yet to be published, though it does make sense
stratigraphically, as both taxa first appear in Late Jurassic Europe and spread
to North America in the Albian, with Late Cretaceous examples known from the
Western North America, Central Asia and Europe. It's also logical anatomically,
as Richardoestesia? isosceles would be expected to have some unserrated and
possibly constricted teeth if it were microraptorian. It should be noted
Paronychodon has priority over Richardoestesia, and lacustris and caperatus
both have priority over isosceles. Also, Euronychodon has priority over
Asiamericana, and portuculensis has priority over both asiatica and asiaticus.
So if this synonymy is proven, none of the names associated with
straight-toothed Richardoestesia will survive synonymization. Longrich (2008)
proposed such a synonymy based on the weak longitudinal ridges on some
Richardoestesia teeth, but Larson (2008) noted other contemporaneous theropods
sometimes have weak ridges too (tyrannosaurids, 'velociraptorines') and that
varied morphologies probably reflect positional variation in Paronychodon
teeth. Thus it is unlikely they existed in the same jaws as Richardoestesia
HOWEVER, Hwang (2005, 2007) found that Paronychodon teeth are identical in
enamel microstructure to serrationless troodontids like Byronosaurus and IGM
100/1323, while Richardoestesia more closely matched dromaeosaurids. So their
proposed synonymy is incorrect.
Sankey, 2002. Theropod dinosaur diversity in the latest Cretaceous
(Maastrichtian) of North America. Journal of Vertebrate Paleontology. 22(3),
Hwang, 2005. Phylogenetic patterns of enamel microstructure in dinosaur teeth.
Journal of Morphology. 266, 208-240.
Hwang, 2007. Phylogenetic patterns of enamel microstructure in dinosaur teeth.
PhD thesis. Columbia University. 274 pp.
Larson, 2008. Diversity and variation of theropod dinosaur teeth from the
uppermost Santonian Milk River Formation (Upper Cretaceous), Alberta: a
quantitative method supporting identification of the oldest dinosaur tooth
assemblage in Canada. Canadian Journal of Earth Science. 45, 1455-1468.
Longrich, 2008. Small theropod teeth from the Lance Formation of Wyoming, USA.
in Sankey and Baszio (eds). Vertebrate Microfossil Assemblages: Their Role in
Paleontology and Paleobiogeography. Indiana University Press, Bloomington,
Ind.. pp. 135-158.
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