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Re: Stonesfield theropod OUM J13506

COMMENTS: I am not going to dignity this with a
scientific response (or a personal response, which
would, needless to say, remove me from this valued
forum). Suffice it to say, that from the 1940s to his
untimely death, my friend Sam Welles spent over 4
decades studying theropods, and his efforts were
renewed when John Ostrom (in 1969) and Jim Madsen (in
1976) both published major, still influential
monographs on theropods. Sam spent weeks with the
OUM/BMNH/SDM Stonesfield theropod specimens,
photographing, measuring, describing (just as he would
do in U.S. and Canadian museums). He was a cautious
scholar (one major 1984 monograph on theropod
osteological comparisons), who, in private, was witty,
with a nearly encyclopedic knowledge of theropod
osteology he was never hesitant to share. I never
heard once Sam Welles say anything but positive
thoughts about the emerging work of Phil Currie in the
1980s. I do not believe dinosaur science is served
with x vs. y personal dichotomies, a Currie vs. Welles
scorecard of scholarship. I shall not engage in it,
because I see no "conflict". Phil Currie's work, like
that of Thomas Holtz et al., are pieces of an
evolutionary jigsaw puzzle, as it were. I do not have
paleodeities, Jaime. There are scholars for whom I
have profound respect, who unhesitatingly share
thoughts and dreams. And "peer review" -- a little
more formal way for dinosaurologists to refine their
extrapolations in the sounding-board of dinosaur
SCIENCE -- is nothing to be feared. When I publish, my
revisions of Sam Welle's unfinished dialogue with the
dinosaur world will be examined.
--- "Jaime A. Headden" <qilongia@yahoo.com> wrote:
> On the ongoing Stonesfield problems (how British of
> me):
> Stephan Pickering (stefanpickering2002@yahoo.com)
> wrote:
> <Compared with the ceratosaur Walkersaurus hesperis
> BMNH R332, it has a
> very different shape, the subnarial plate differs in
> reaching the
> premaxilla laterally. The nasal process is less far
> back. The height of
> the caudal plate decreases less gradually. The
> recess is shallower. There
> are 11 teeth in 320 mm vs. 11 in 250 mm, but the
> teeth are larger and so
> are more crowded. The teeth differ in the
> mesiolateral bulging and basal
> medial thickening. The 4th vs. 5th tooth is below
> the centre of the nasal
> process.>
>   It is very peculiar to hear of *"Megalosaurus"
> hesperis* being a
> ceratosaur, and I would very serious like to know
> what is concluded to its
> status as a ceratosaur?
> <Currie and Zhao in 1994, positioned
> Yangchuanosaurus in Sinraptoridae, on
> the basis of the "arrangement of the accessory
> fenestra in the antorbital
> fossa", but did not, of course, analyze the
> hypodigms of the
> Megalosauridae as I have constituted it.>
>   I could detail Currie and Zhao's actual diagnosis
> for Sinraptoridae and
> detail the list of characters both *Y.
> shangyouensis* and *S. dongi* share
> to the exclusion of other basal tetanurans, but it
> would go on. The study
> was a result of over several years of research after
> the two supervised
> the excavation of the type Chinese taxon. This is
> saying much for one whom
> is not very arguably the best expert on theropods
> extant (Welles'
> expertise was not, despite claims, on theropods),
> being Phil Currie.
> However, the diagnosis in the mandible went beyond
> generalized fossae in
> the maxillae, but involved a complete invagination
> with unique maxillary,
> confluent nasal fossae, fenestrae, internal
> chambers, medial laminae,
> maxillary fenestra position, maxilla shape, tooth
> size and arrangement,
> and so forth. As yes, they did not analyze Stephan's
> hypodigms because he
> did not, at the time, ever present them, and nor do
> I think it would have
> worked: Currie and Zhao, however, did in fact
> compare the forms to work by
> Britt on *Torvosaurus*, used Dong et al's work on
> *Yangchuanosaurus*,
> Gilmore's and Madsen's on *Allosaurus*, etc. More
> recent work, including
> that of Holtz in 1994 and 2000, reviewed the
> relativity of *Baryonyx*, and
> now we have *Afrovenator* from Sereno et al. and
> Allain on
> *Streptospondylus* with Chure on *Poekilopleuron*.
> Chure is also reviewing
> on other taxa, and a monophyletic and very robust
> clade of Sinraptoridae
> is in evidence.
> <Recent efforts to use Megalosauridae without
> Megalosaurus bucklandii are,
> needless to say, not tenable.>
>   Allain did not give reasons to using
> Megalosauridae, so any argument is
> fairly weak. Only Allain has used Megalosauridae to
> label this group in a
> phylogeny, and this is where we must consider the
> issue. It is a component
> of science that provability be entered without
> prejudice, and that work be
> evaluated on its own merits, not on "intents" and so
> forth of why things
> are used without verification.
> <Not acceptable, too, is the opinion that
> Megalosaurus bucklandii must be
> restricted to Buckland's mandible (neither Buckland
> nor von Meyer chose a
> type specimen; it is OUM J13505, the rostral right
> dentary + the
> kleptotype specimens listed below), nor do I accept
> the opinions that
> Buckland's original figures of a partial skeleton
> are not from the same
> individual.>
>   And still the evidence is shaky, based on a single
> quarry ... to my
> knowledge, all the Stonesfield elements are the same
> color and
> preservational condition, implying a similar burial
> period, and being of
> similar size means nothing if in fact gregarious
> animals are involved or
> its a common kill site, as in some Utah or Alberta
> localities. And
> appologies to the memory of Sam Welles, but he is
> not a paleo deity. Any
> professional can be wrong, just as I may be [not a
> professional, but I can
> still be wrong, and perhaps more so as I am only a
> student :)]. It is
> certainly problematic to be relying on the word of a
> manuscript or set of
> them, never published or subjected to review or
> verification from experts
> in the field.
> <Megalosauridae consists of Megalosaurus (including
> Torvosaurus),
> Metriacanthosaurs, Eustreptospondylus, and
> Poecilopleuron/Poekilopleuron
> (the former spelling, it seems to me, will prove to
> have priority, as the
> earliest publication I am aware of uses it, although
> I am still awaiting
> word on elusive pre-1838 abstracts).>
>   I recently have found that no type was designated
> for *Therizinosaurus*,
> reflecting on the then current ICZN dictum where a
> type must be designated
> to validate a name and usage, but this has been
> assisted by follow-up work
> by Maleyev who used the specimens numbers as the
> type, but not in any
> designatorial work. The first major paper discussing
> the claws and
> indicating the type was by Barsbold, so does this
> mean that Barsbold
> carries the name? The first reference work on
> *Poekilopleuron* (and I have
> his first) by Eudes-Deslongchamps with a specimen
> allocation and figures,
> is the monographic work, and frankly, the spelling
> is clear in the title
> despite the fact that the name is treated as having
> been coined previous
> to the work. Still, one may then just use the
> monographic work as the
> first valid allocation of a name, description,
> comparison, and type
> designation with illustration and therefore the date
> carried in the work.
> I need to check on Allain and Chure and see how they
> treated the subject
> in their historical review.
>   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.
> __________________________________________________
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