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Re: JVP 25(3)

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Skull kinesis in a salamander? I guess the skull is simply so poorly ossified
that many fontanelles are wide open and some bones missing altogether (is there
a quadrate?).>

  The skull is well ossified in all three described skulls. My reasoning for
this are the weak connections between palate bones and the nearly transverse
suture between frontal and nasal, while the frontal and parietal show an
interdigitating suture. No fontanelles between bones aside from the pineal
foramen are present, so this animal was a neotenic adult. The argument I
forward is that the skull may exhibit some ability to plastically deform in the
anterior 1/3 of the skull, especially at the pterygoid/palatal and
nasal/frontal contact zones. A wide gape, weakly to unossified but preserved
gill arches, and a broad jaw with anteriorized thaumatic structures (weak
maxilla with palatal teeth the most prominent dentition, suggest to me that a
cranially kinetic mechanism may have been at play. Unlike other basal
urodelans, the nasals are actually pretty long in *Jeholotriton* compared to,
say, *Sinerpeton* (Gao and Shubin, 2001).

<So they don't even put it in Cryptobranchoidea?>

  Why would they?


Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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