Re: Emus a Model for Dinosaurs?

[Michael Skrepnick <palaeopaint@dinosaursinart.com>]

So if the point of attachment of m.caudofemoralis along the length of 
femoral shaft affects either speed or power of retraction depending upon 
placement, what purpose does the trochanter itself serve other than more 
surface area for muscle attachment or subtle change in leverage. . . 
further, as Deinonychus and Velociraptor do share similar overall 
morphology, what mechanical advantage is gained by the addition of a 
trochanter in the smaller form?


Mike S.


> Michael Skrepnick wrote-
>
> > Lack of a 4th trochanter would seem to be a far more overwhelming obstacle 
> > to performing traditional bipedal theropod locomotion ( where then in fact 
> > is the origin for a caudofemoral retractor in Caudipteryx? ) than the 
> > alternative, a primitive knee driven movement supported by slender femora. 
> > . . essentially, does a missing 4th + "convergent?" knee driven locomotion 
> > trump the lack of a derived ( if even necessary? ) robust femor ?
>
> The absence of a fourth trochanter in itself probably had little effect on 
> locomotion.  Velociraptor's femur has a large fourth trochanter, for 
> instance, while that of Deinonychus lacks even a discernable scar.  Yet 
> the genera are extremely similar in morphology otherwise, and Deinonychus 
> certainly lacks neornithine proportions.
>
> Mickey Mortimer