[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Archaeopteryx versus Confuciusornis



Have seem the Naturwissenschaften paper by Zhou et al. comparing Arch and
Conf. The main problem is the wildy inaccurate restoration of Archaeopteryx.
Among other things, their skull has no superior temporal bar or descending
process of the squamosal, both of which were definitely present. The lack of a
postorbital bar is questionable. The shallow pelvis with an extremely
retroverted pubis is sheer fantasy, the pubis was at most modestly retroverted
and may have been nearly vertical. The vertical body posture and habitually
dorso-flexed tail is also improbable. Archaeopteryx is far less avian and like
Confuciusornis than they claim. 

As for the latter, they continue to restore the hindlimbs as too long, with
the femur subequal in length with the humerus. Actually the femur was about
15% shorter, and the hinlimb was rather reduced. 

What is most interesting is the presence of a large postorbital forming a
complete postorbital bar in Conf. At first I was skeptical, until I looked at
the photograph of the skull in Feduccia 1996 and there it is as plain as day!
The presence of a complete postorbital - which should have hindered or barred
avian kinesis - in such an early bird has important implications. The case for
a complete bar in Archaeopteryx is strengthened. Yet alvarezsaurs lack a the
bar and have other adaptations that should have allowed kinesis. Either
alvarezsaurs inherited their incomplete bar from more basal avians, developed
one independently, or Conf reversed and reevolved a complete postorbital. No
way to tell at this time. 
But at least a complete postorbital no longer bars a theropod from being
closer to other birds than Archaeopteryx:) 

On a related matter, it may look like Protarchaeopteryx lacks a reversed
hallux in photos. Direct inspection reveals that one hallux is directed away
from the metatarsals, the other towards them. Both are too damaged to tell
which is correct. Not that it is a definitive character, kiwis do not have a
reversed hallux. 

GSPaul