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Re: [Sub]Arctometatarsalia

>   The subarctomet pes is properly applied to those taxa which bear a
> pinched third metatarsal between the second and fourth, but is not
> occluded from expression on the extensor or flexor surfaces of the
> metatarsus itself. In this manner, the subarctomet pes is found in
> Oviraptoridae, *Caudipteryx*, *Velociraptor* and *Deinonychus*,
> *Nedcolbertia*, the unnamed Arkansas pes (in the *Nedcolbertia* paper),
> and probably *Ornitholestes* as well.

These forms have IMHO a compressed (shortened) version of the condition seen
in *Sinornithosaurus*, NGMC 91, *Microraptor* and *Caudipteryx* for which
the term "subarctomet" was invented.

>   As noted before, the "normal" arctomet pes is known in Ornithomimidae,
> *Garudimimus,* possibly *Harpymimus,* Tyrannosauridae, Troodontidae (incl.
> *Sinovenator*), *Microraptor,* and *Sinornithosaurus.*

In *Sinovenator*, *Microraptor* and *Sinornithosaurus* mt II and IV don't
touch as required for having a classical arctometatarsalian foot. Therefore
they are sub-. In caudal view at least (cranial unknown), *Sinornithoides*
also has this condition, and so does "*Ginnareemimus*", whatever it is and
however it will be spelled.

>   *Archaeopteryx* and other Aves are not arctomet, subarctomet, or
> hyperarctomet in any fashion. This is a reversal under nearly any possible
> position for these taxa within Coelurosauria.

*Archaeopteryx* and *Rahonavis* have the full plesiomorphy; either this is a
reversal, or (depending on the cladogram) the sub- condition evolved
independently at least twice, once in later "dromaeosaurs", another time in
oviraptorosaurs (wisely holding off any judgment on the position of
troodontids...). "Other Aves", namely *Yandangornis*, *Hulsanpes*,
*Sapeornis* and early Pygostylia like Confuciusornithidae and
*Iberomesornis*, in which the bones aren't overfused yet, have a particular
type of sub-: mt III is slightly constricted in the middle, but broadened at
its proximal end. This is probably a synapomorphy.