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Re: Defunct genera and _Pekinosaurus galtoni_

Tim Williams wrote:

<<_Brachyceratops_ and _Monoclonius_ (for the

David Marjanovic wrote:

<What have these been sunk into, and why?>

  Presumably, it has been suggested that *Monoclonius*
be dropped as a nomen dubium without validity and
largely incomparable to other ceratopsids. Most
species have been removed into *Centrosaurus* and
*Styracosaurus.* It has also been suggested (no cites
right now0 that *Monoclonius* and *Centrosaurus*
represent the same taxon. However, the type for *m.
crassus,* type species, is distinct from all other
centrosaurs and chasmosaurs except for possibly
*Brachyceratops* itself. I belive there was also a
suggestion that Brachy and Monoclone are sympatric and
therefore synonymous. But that may be due to
plesiomorphy. *Brachyceratops* and *Monoclonius*,
according to Dodson (1996: _Horned Dinosaurs_),
Penalski and Dodson (1999: _JVP_), do possess some
autapomorphies that would be valid relative to the
ontogeny of ceratopsids. This in support of the
position of *Avaceratops* as a valid taxon in the
basal centrosaurine lineage, to which both the
preceeding taxa and also possibly *Ceratops* could
pertain. Anyway, there's extensive literature out on
this, and Dodson's book is a good place to start from
with regard to references and discussion, though it
may not be the most authoritarian volume.

  A new centrosaurine from the Oldman Formation (_JVP_
19(suppl. to 3)) without caudal hooks and unusual
ornamentation may help resolve this position.
<<and _Maleevosaurus_ and _Nanotyrannus_ (for the
Tyrannosauridae) are four more genera who have bit the
dust, and to me their passing seems justified: the
most parsimonious explanation appears to be that their
"diagnostic" characters are juvenile/subadult traits. 
This only becomes apparent after comparison with
species for which growth series are known.>>

<<...and I have doubts about whether _Jurapteryx_ is a
young _Archaeopteryx lithographica_.>>


  Read Howgate, 1984, 1985 (_Beginnings of Birds_,
Viohl et al., (eds)), on the Eichtätt *Archaeopteryx*
which he first distinguished as a new species, *A.
recurva* then as a new genus *Jurapteryx recurva.*
Limb proportions do not appear to reflect trends in
ontogeny of the other specimens, suggesting separation.

Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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