the transverse ligamental groove

["Mickey Mortimer" <mickey_mortimer@email.msn.com>]

While compiling my theropod synapomorphy list, I found two characters with
separate distributions that seem to be the same.  Can anyone help me out?
The first is from Sues and Makovicky's Microvenator paper.  It is "humeral
head offset and emarginated ventrally from pectoral and bicipital crests by
groove".  It is said to be present in Microvenator, alvarezsaurs,
dromaeosaurs, troodonts and birds.  This seems very similar to the "distinct
transverse ligamental groove" that is used as an ornithothoracine
synapomorphy in the Rahonavis paper, the Shuvuuia paper and the
Caudipteryx/Protarchaeopteryx paper.  I've checked the literature and
Deinonychus and Patagonykus, for instance, seem to have this condition, as
do birds like Ichthyornis.  Can someone please tell me if these characters
are indeed referring to the same condition?  If so, why the different
interpretations, and if not, what is a transverse ligamental groove?  Thank
you in advance.

Mickey Mortimer