Re: Microraptor did not sprawl!

[GSP1954@aol.com]

Yes it did. Having personally seen a number of Johel dromaeosaur specimens 
(all of which can probably be placed as minor species variants under 
Sinornithosaurus) I have seen no femoral head that has the classic, transversly 
broad 
cylindrical femoral head typical of avetheropods, including most large 
flightless 
dromaeosaurs. All sinornithosaur femoral heads are modified from the typical 
pattern in a manner that would allow considerably larger lateral play, 
although just how far is not certain. This is verified by the fact that the 
Sinosauropteryx type skeletons are consistently preserved on their sides in the 
standard patttern of the strongly erect legged theropods, as are the 
articulated 
Archaeopteyx which have a standard theropod femoral head (see DA). In contrast 
many of the sinornithosaur specimens are preserved sprawled legged, which would 
occur only if the legs could readily splay out. Other specimens are on their 
sides, showing the legs could be held erect, and therby confirming a wide 
lateral range of motion. This makes sense considering that sinornithosaur legs 
were 
bearing fully developed wings far beyond what was needed just for auxiliary 
control surfaces, they were also being used to generate extra lift, about as 
much as the arm wings. In contrast the much smaller leg feather array on 
Archaeopteryx was too small to form a wing, they were primarly control surfaces 
probably used in special maneuvers such as landing air brakes, etc. Since they 
did 
not generate lift there was no need for the legs to be able to sprawl. 

G Paul