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Jaime Headden wrote:
<<1) The first type is dorsal fusion, with mtIII adducted between II
and IV (it is not actually "pinched") so this is not a true
arctomet foot. An elmisaurid foot, basically.>>
Certainly. Elmisauridae was scored as having an arctometatarsus in Holtz
1994, so that's why I included it as a type of arctometatarsaly. Elmisaurids
or caenignathids or whatever they're called... are closer to oviraptorids.
<<2) The arctomet foot, with mtIII "pinched" between mt's II and IV, not
reaching to proximal surface as in . This is seen in
tyrannosaurs and bullatosaurs, suggesting closer relationship than
any other groups (tyrannos and ornithos and troodonts, excluding
Additionally, MT III is somewhat sigmoid at its distal end. The proximal end
of MT III is reduced at the tarsus.
<<3) The enantiornithine foot, with mt's II-IV fused along full length
without pinching or adduction of mtIII.>>
How is this an arctometatarsus? Maybe Tom can clarify this, but doesn't an
arctometatarsus require MT III to be pinched?
<<4) Apparently, the alvarezsaurid foot may be a variation on types 1 or
3, or its own type, with mtIII adducted _and_ fused proximally and
distally, mtIII appearing only in posterior and distal aspects,
totally occluded from proximal and dorsal except at the plantar
MT III is not just adducted, but it is reduced proximally, like a true
arctomet pes. I believe it is so reduced in _Parvicursor_ that it does not
even reach the tarsus proximally.