[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

thinking about bird and theropod feet



Several postings this morning got me thinking about the stability of bird
and theropod feet.  Please note that i am venturing into pure speculation
and into the balliwack of To(i)m Holtz.  

Let's assume for a sec that you have an animal leaping out of trees
as the pouncing scenario suggests.  Would you not expect the feet to
adapt to better produce the stability needed in a landing.  If you are
bipedal, i think but am not at all sure (and i know someone will correct
me ;) ) that the broader theropod foot might be more stable at providing
a landing, esp compared to a narrow long foot like in the early 
narrow three toed versions (i.e. Grallator if i have the name right).
I recall here that the theropod track has a very broad interangle (~ 60o??)
if you then allow that animal to evolve more efficient flight, would
you not expect the foot to narrow again, esp. if the animal stops
needing to land on the ground and again spends more time landing in 
trees.  (recalling here that the bird foot is narrower in its intertow
(make that intertoe) angle (closer to 40o??)

these again are early morning reveries - comes of trying to get the worms
before every one else!
b

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Bonnie A.B. Blackwell,                          bonn@qcvaxa.acc.qc.edu
Dept of Geology,                                off: (718) 997-3332
Queens College, City University of New York,    fax: (718) 997-3299
Dept of Earth \& Environmental Sciences,        fax: (718) 997-3349
The Graduate Center, CUNY,                      fax: (718) 997-3513
Flushing, NY 11367-1597                         messages: (718) 997-3300