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Re: Questions about Diplodocus, Pelicaniminus and more



At 7:54 AM 8/26/95, FUCCI@CERNVM.CERN.CH wrote:
>Diplodocus
>Is it possible that Diplodocus (or other sauropodes which have nostrils
>highly placed on the skull) can have a trunk like elephants?

        This argument has been put forth before, although I've rarely seen
it taken seriously.  The most typical counterargument for a trunk is that
trunks are heavily muscled appendages, and leave huge and obvious muscle
scars on the skull bones surrounding the nasal openings.  Such muscle scars
have never been observed in any sauropod skull; hence, the likelihood of
_Diplodocus_ (or any other sauropod) having a trunk is remote.  Besides,
with the specializations (read:  length) of the neck, why on earth would a
sauropod need a trunk?  The whole _neck_ is a trunk!  8-)

>Pelicanimimus
>I would like to get a maximum of informations about Pelicanimimus.
>How can we know that Pelicanimimus had a foodbag like pelicans?
>Is there any life restoration of this animal?

        I haven't personally seen any reconstructions of this weird animal
except the head drawn for the original article in _Nature_:

Bernardino, P.P, Sanz, J.L., Buscalioni, A.D., Moratalla, F.O., and
Rasskin-Gutman, D. (1994).
        "A Unique Multitoothed Ornithomimosaur Dinosaur from the Lower
Cretaceous of Spain,"
        _Nature_ 370:  363-367.  (that's August 4, '94).

We know that this specific dinosaur had a "throat pouch" a la pelicans
(hence the name) because this fossil comes from the
rapidly-gaining-notoriety Las Hoyas site near Cuenca, Spain, which is a
_lagerstatte_ lacustrine limestone of Lower Cretaceous age, and all kinds
of neat things are preserved there.  One of them was a set of skin
impressions associated with the _Pelecanimimus_  (and, BTW, note that the
spelling is "pelEcan," not "pelIcan," as the scientific name of the pelican
is _Pelecanus_!) fossil, which included a small "pouch" in the throat, as
well as a small "occipital crest" impression.

>Homalocephal
>I've red a theory in a book edited in 1985 wich indicates that Homalocephal,
>who have a large pelvis, could perhaps give birth like mammals.
>Is this theory still valid?

        You're referring to the pachycephalosaur called _Homalocephale_
(pronounced "HOM-a-lo-SEPH-a-lee," to help you remember the "e" on the end!
;-)  ).  I'd not heard the "live birth" issue attributed specifically to
this dinosaur, but in a more general sense, the wide pelvic canals of many
different dinosaurs have been used to assert live birth in those dinosaurs.
The subject has been bantered about in this forum many times in the past.
Until we actually find eggs with embryonic remains for each of these
dinosaurs, however, one cannot say with 100% certainty that these dinosaurs
_didn't_ lay eggs...but that is what is called "negative evidence" --
making a conclusion based on a _lack_ of evidence, rather than on something
tangible.

        Nevertheless, people make assertions one way or another.  The live
birth issue is more typically centered around sauropods.  We don't as yet
have any eggs containing sauropod embryos proving that sauropods laid eggs
(which means it _is_ within the realm of statistical probability that
sauropods gave live birth), but we also have very large eggs and nests from
regions where large, common animals were sauropods.  These are generally
attributed to sauropods, although again, until we find one with actual
embryos inside, this attribution can't be made with 100% certainty.  Still,
at least to my way of thinking, I find it much more likely that the
attribution is correct, and that sauropods laid eggs.

        Similarly, since so many different dinosaurs laid eggs, and since
their descendants (birds) and cousins (crocs) all laid eggs, I'd be willing
to bet that all the dinosaurs did, too.  This isn't a fact -- it's still
based on negative evidence! -- but it's one opinion.



Jerry D. Harris
Shuler Museum of Paleontology
Southern Methodist University
Box 750395
Dallas  TX  75275-0395
(214) 768-2750
FAX:  (214) 768-2701
jdharris@lust.isem.smu.edu
        (Compuserve:  73132,3372)

---------/O\------*     --->|:|:|>     w___/^^^\--o

"If it looks like a duck, walks like a duck, and
quacks like a duck, then it is the sister taxon to,
but cannot parsimoniously be, the direct ancestor
to all other ducks."

                                --  _not_ W. Hennig

---------/O\------*     --->|:|:|>     w___/^^^\--o