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Re: JVP 25(2): New Dinos, Birds, Discoveries



Yates, A. and C. C. Vasconcelos. 2005. Furcula-like clavicles in the 
prosauropod dinosaur *Massospondylus*. _JVP_ 25(2):466-468.

Interesting... I've seen Plateosaurus clavicles before. I've also seen 
numerous assumed Syntarsus clavicles fused medially. I've also seen an 
articulated 
Syntarsus lacking a fusion between the two rami, but certainly articulated with 
a central element that could be called a hypocledium without much fear of 
contradiction.

Variations happen.

Yates and Vasconcelos' paper does show that clavicles most likely had 
separate points of origin in development. Some of Feduccia's crew have been 
trying to 
state how development shows that the furcula developed from a singular 
origin, which makes it yet again, yes, you guessed it, "homoplasy". This 
premise 
that developmental elements only alter later aspects of development are not 
based 
in reality. Heck, look at embryo formation in frogs, reptiles and birds, then 
in humans. The "yolk" factor changes many aspects of early development while 
preserving later ones between these groups...

Come to think of it... I believe that there was a quail study a few years 
back in The Journal of Morphology that indicated a separate origin for both 
rami.

Kris
http://hometown.aol.com/saurierlagen/Paleo-Photography.html