Re: Notarium question

["Jaime A. Headden" <qilongia@yahoo.com>]

David Peters (davidrpeters@earthlink.net) wrote:

<No, Jaime, I was referring to a _new_ bone. One _above_ the fused
dorsals. Don't have the Renesto reference at hand. Will try to find.>

  Ah, my mistake; the paired, L-shaped bones that Renesto notes in 1994
would, indeed, be neomorphic; Silvio is, fortunately, working on the
identity of these bones and I cannot wait to see his work when it comes
forth. My assumption was looking at structures similar to the notarium,
which would not be neomorphous in the sense that you provide (its a fusion
of structures, rather than a new structure). In this manner, I can think
of few, such as those mentioned earlier (though I think the appearance of
palatal ramal teeth on the premaxillary bone of *Haptodus* that David
mentioned is likely not to fit the bill of a neomoprhic bone or structure,
as the tooth germs were likely just distributed in the derm prior to
budding). In alvarezsaurids, the unknown possibly ethmoidal bone on the
midline of the skull is likely a neomorph, and may or may not be
homologous to the ethmoid of birds (which is paired). Previously
uncommented neomorphs include the occipital crown horns of some lizards,
ceratopsids (exoccipitals), the epijugal horn of the ceratopsids, and the
[non-paired and likely neomorphic] epinasal horn of centrosaurines.
Xiphisternal endochontral ossifications in mammals are neomorphic; I think
the "thumb" of pandas (a pisiform) is convergent among synapsids and only
uniquely derived in the ursids, so allusions by some to a neomorph may not
be correct, because the pisiform occurs in other animals. Many mammals
have unique sesamoids below the joints of their wrists/ankles/hocks and
the interphalangeal/digital/metacarpo-phalangeal joints.

  So perhaps this works best?

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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

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