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POSTORBITAL BARS



George wrote..

> The skull of Archaeopteryx in almost all recent reconstructions is too
> birdlike for Archaeopteryx to be ancestral to dromaeosaurids--unless you
> hypothesize a number of difficult reversals, such as reappearance of the
> postorbital bar and reseparation of the temporal and orbital openings. So
> dromaeosaurids diverged from the bird lineage before archaeopterygids.

I'm still confused about the condition of the postorbital bar in _Archaeopteryx_
- and yes I know it is one of *the* issues of controversy between certain
ornithologists and dinosaur palaeontologists. Absence of the postorbital bar in
_Archaeopteryx_ would make it more like modern birds: the situation certain
ornithologists 'want'. Conversely, presence of the postorbital bar in
_Archaeopteryx_ would make it more like non-bird theropods: the situation some
dinosaur palaeontologists 'want'.

So it's a bit of a pain that this region of the skull is deformed or destroyed
in the specimens that have skulls, meaning that we have to rely on
reconstructions. Reconstructions of the Eichstatt specimen skull provide it
variously without a postorbital bar and with confluent orbital-temporal fossae
(e.g. Martin and Witmer), or with a postorbital bar (e.g. GSP figure in
Chatterjee's 1991 _Protoavis_ paper). I can't make out which looks more right -
 and what a shame that the skull of _Archaeopteryx bavarica_ is no great help
(unless I'm remembering incorrectly - someone check the Wellnhofer and
Elzanowski 1996 _JVP_ paper).

But if anything's clear, it's that we >can't be sure< that _Archaeopteryx_ is
more like modern birds in this aspect of its anatomy. 

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This email dedicated to the memory of Noel the Green anole. Noel passed away in
his sleep last night after a difficult period of slow deterioration during which
he refused to eat and eventually drink. To the knowledge of his carers, he was
the oldest Green anole in captivity in the UK, having been obtained in the May
of 1990 when he was already a fully grown adult. Noel was also unique in having
a bizarre Z-shaped tail tip: the result of a run-in with a large carabid and a
sad accident involving a fish tank lid during which he also lost 2 toes on his
right hind limb. Despite these afflictions, we hope he led a happy and very
lizardy existence and we hope he now chases mosquitos and spiders in the
Floridan treetops: the anole heaven all good anoles go to.

DARREN NAISH