Re: Thescelosaurus question

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

Simon Clabby (dinowight@yahoo.co.uk) wrote:

<Not entirely true. Dermal armour in Hypsilophodon has been recorded,
albeit on only one specimen, BMNH R2477, from the Isle of Wight. These
"osteoderms" were described as irregular polygons, with "one surface
granular" and "the other smooth and furrowed by a vascular net", and were
found near the skull, (Hulke, 1874). Nopcsa (1905) also noted this, and
even figured them (1905, fig. 1), as did Hulke (1874, Pl 3, fig 1).>

  I would have to hesitantly disagree: the presence of dermal
ossifications in dinosaurs is rare, restricted almost entirely to two
subclades (Thyreophora and Titanosauria). The presence of the elements in
*Hypsilophodon,* however tantalizing, have never been confirmed as
ossicles or even dermal in nature. There are dermal "nodes" found in
impressions of the posterior belly region of lambeosaurine hadrosaurids,
but not as ossifications. Three linear "ossicles" lie abutting the distal
(dorsal) scapula of *Talenkauen,* possible representing dermal ossicles;
these are confined in a single row and are scutellate in shape (small,
round, a central apex, and bear smooth margins). *Ceratosaurus* also have
a few tiny ossicles in a linear row found sagittal above the anterior
cervical series. 

  This [ ^-- ] is currently an imprecise concensus for dinosaurs. But
then, this is also paleontology: there are NO "yes or no" answers in "if"
questions.

  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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