Re: My Phylogeny: Growing Science...

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

David Marjanovic (david.marjanovic@gmx.at) wrote [quoting Sereno et al., 1993: 
*Eoraptor*]:

<"Only a small part of the left maxilla is preserved [...] The interdental 
plates are small
pointed processes, recalling the interdental plates on the dentary of *Troodon* 
(Currie, 1987),
which are not clearly differentiated from the lingual surface of the maxilla.">

  This is true of all theropods, which preserve interdental bone between each 
alveolus dorsally,
as in interdental walls. In caenagnathids, these are relatively reduced, but 
they in troodontids
are bare and distinctly present. However, interdental plates, which are 
T-shaped in section and
have a lateral component that in many theropods fuse to the lingual ridges sent 
off from the
dentary, are completely separate dermal bones. This is a confusing area of 
anatomy, as there have
been several reports of the lingual apicular ridges in troodontid jaws as 
evidence of interdental
plates. Following Currie, 1987, and subsequent cranial descriptions, as well as 
all other jaw
material described for troodontids (see Barsbold, 1974 for *Saurornithoides*) 
have noted the
absence of any true interdental bones. The lingual dentary ridges, present also 
in basal
oviraptorosaurs [actually, most of them], are solid and camellate bone, they 
are not remnants of
interdental plates.

<Are you sure that long ?broken rod fused to the back of the skull is the 
quadratojugal, as in
your drawings, rather than the jugal, as might be guessed from its length?>

  It is reasonable to assume that the portion of the element, without any but a 
small notch on the
lateral surface (Kurzanov, 1987), is the conjoined rostral ramus of the 
quadratojugal and the
caudal ramus of the jugal, considered by Kurzanov (1985, 1987) to be comprised 
nearly entirely of
the jugal. The quadratojugal is a distinct element, but it is fused to the 
lateral surface of the
quadrate, and there is a ventral embayment below the quadratojugal on the 
quadrate that indicates
the presence of a distinct quadratojugal (see Osmólska and Maryanska, 1999, on 
the oviraptorid
quadrate in _Acta Palaeontologica Polonica_).

<This is an adjective. Although it is definitely derived from tooth, my 
dictionary only knows
zubnoy... Do any of the following occur in the text, which I _personally_ would 
expect for
denticles: zubets: tooth, notch..., s zubtsami: serrated, zubok: (diminutive)>

  I recall most of these, but the case is elementary anyway. The term has been 
used for both a
tooth and a denticulation. The word has been used by Barsbold (1983) to also 
refer to denticles on
the tooth crowns. So this term is probably indicative of the pre-2000 reports 
of *Avimimus* teeth,
and should be discounted until true teeth are identified.


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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