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Re: Long-necked stegosaur, head tail mimicry?
Tim Williams writes:
> Speaking of long sauropod necks... there's a new paper in the
> pipeline on _Euhelopus_. Although Wilson & Upchurch break up the
> clade of long-necked Chinese sauropods ("Euhelopodidae", containing
> _Euhelopus_, _Mamenchisaurus_, and _Omeisaurus_), they baulk at
> erecting (or defining) a new Euhelopodidae, which would include
> _Euhelopus_ and _Erketu_.
I should think so! It would be disastrous to resurrect that name to
denote a completely different clade from the one that it has been
universally understood to mean.
By the way, note the (rather poor) phylogenetic definition of
Mamenchisauridae in Naish and Martill (2007:498) --
Mamenchisauridae Young & Chao, 1972, a clade that we here
diagnose as all those sauropods closer to Mamenchisaurus
constructus Young, 1954 than to Saltasaurus loricatus
Bonaparte & Powell, 1980 ...
I don't know, those University of Portsmouth guys.
> Nevertheless, it's clear that *very* long necks evolved at least
> twice in the Sauropoda - in the non-neosauropods (_Mamenchisaurus_,
> _Omeisaurus_) and basal titanosauriforms (_Euhelopus_, _Erketu_).
At least FOUR times -- in Mamenchisauridae, Diplodocidae (the neck of
Supersaurus is best estimated at 15m, longer than any other),
Brachiosauridae sensu stricto and once or more within the huge,
ill-defined cloud that is Titanosauria. This is covered briefly by
Matt Wedel's 2006 SVP abstract:
(page 103 of the PDF) and in much more detail in chapter four of his
(pages 200-263 of the PDF). Irritatingly, this chapter is the only
one in the dissertation that has not yet been published.
/o ) \/ Mike Taylor <firstname.lastname@example.org> http://www.miketaylor.org.uk
)_v__/\ "Clear use of function pointers is the heart of object-oriented
programming" -- Rob Pike.