[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Wilkinson's new pterosaur paper
Jim Cunningham wrote:
>It is possible for pterosaurs to fly with a wing/hindlimb connection, and I
>expect some did. It is also possible (and more efficient, given the
>ecological niches they seemed to tend to occupy) for them to fly with the
>wing independent of the hindlimb, and I expect some did that as well (in my
>personal opinion, most were probably independent, but I don't consider that
>to be proven).
Perhaps it is theoretically possible to fly with either configuration, Jim.
But first evidence must be shown that even _one_ pterosaur had a deep chord
configuration. So far, in the widest possible variety of pterosaurs, there is
no evidence for a wing tip to hind leg connection.
Nor is there any phylogenetic trail of precedents exhibiting a finger-tip to
hind leg connection. Rather, the phylogenetic trail demonstrates the
wing-finger to elbow connection only.
The two wing configurations 1) wingtip to elbow and 2) wingtip to thigh are
fundamentally different. The first has its origin distally, like a bird. The
other proximally, like a flying squirrel. You cannot have one AND the other in
the same clade.
If I'm wrong, please send the jpeg evidence that will improve my understanding.
PS In communications with Phil Senter he agreed that Unwin was wrong about the
'skull roof' of Sharovipteryx and that an interpterygoid vacuity was indeed
present between the two largest bones making them palatal. He had assumed that
Unwin's observations succeeded mine, but actually, with both papers published
in 2000, neither of us had access to the work of the other.
Phil drew an antorbital fenestra in his Cosesaurus illustration, but then said
one was not present. Strange. Phil also mistook the ventral edge of the keel
and the left scapula for curved disarticulated clavicles in Cosesaurus. Only a
few sacrals are disarticulated in Cosesaurus, no other bones. The real
clavicles are in place on the anterior rim of the coracids, they overlap
medially and they are straight.
Phil also did not have access to Ellenberger's unpublished photos of Cosesaurus
taken from every angle and magnification. While Ellenberger's interpretations
were a little off the mark, his data collection was fantastic.
I'm also having trouble making sense of Senter's matrix and he's unable to
help. He lists 215 characters, but his matrix only has 150 or so characters. So
it's impossible to match them up.