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New paper on pedal function in deinonychosaurs



Here's a new paper by Phil Senter:

SENTER Phil. Pedal function in deinonychosaurs ïDinosauriaï Theropodaïï 
a comparative study. - Bull.Gunma Mus.Natu.Histï.13ïï1ï14, 2009

Abstractï Members of the Cretaceous theropod clade Deinonychosauria have a 
highly modified second toe with an enlargedïrecurved ungualï Here I present 
the first comparative study of pedal function in deinonychosaurs and other 
theropods to test hypotheses of function for this toeïI manually
manipulated bones and casts to determine pedal range of motion in the 
non-deinonychosaurian theropods DilophosaurusïAllosaurusïMononykusïand 
Chirostenotesïand the deinonychosaurs TroodonïNeuquenraptorï
RahonavisïBambiraptorïDeinonychusïand Dromaeosaurusï I also used movies 
of walking bird feet for comparisonïThe results of the study show 
thatïï1ï contrary to previous suggestionsïthe distodorsal eminence of 
pedal phalanx II-1 of deinonychosaurs is not correlated with greater 
hyperextensibility of phalanx II-2 than in other theropodsïï2ï the 
proximoplantar process of phalanx II-2 of deinonychosaurs limits flexionïas 
previously suggestedï3ï movement of the second toe is sub-orthal in 
dromaeosauridsïthe toe remains adductedïangled toward the animalâs 
midlineïthrough hyperextension and flexion in Troodonïand in other 
theropods the second and fourth toes diverge during hyperextension
and converge during flexionïï4ï pedal phalanx I-1 is immobile in 
Chirostenotes and the examined deinonychosaurs but has a wide range of motion 
in other theropodsïï5ï contrary to a previous suggestionï
the hallux of Rahonavis was not retrovertedïï6ï range of motion in the 
second toe is consistent with opening tough insect nests in dromaeosaurids but 
not Troodonïï7ï the deinonychosaurian second toe
was hyperextendedï not flexedï during locomotionï

Cheers, Michael
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