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GASTROLITHS & OTHER ASSORTED
Earlier today I wrote a long email about gastrolith
distribution in theropods, its relevance for dinosaur biology,
and loads of other stuff. Then the PC locked up and, to cut a
long story short, all was lost. Hooray for computers.
Anyway, tis I, post-therapy reformation.
As Dave Varricchio noted in his paper on tyrannosaurid
stomach contents, popular views about the distribution and
use of gastroliths in dinosaurs need to be revised (so this is
preaching to the largely converted, and most of this has
been discussed on DML before anyway). The fact that
gastroliths are present in _Lourinhanosaurus_,
_Poekilopleuron_, _Baryonyx_ and a tyrannosaurid
demonstrate that gastroliths are not unique to herbivorous
dinosaurs. _Protorosaurus_ and aberrant stomach contents
aside*, I think the possibility that these theropod taxa were
herbivorous is rather unlikely, and given that non-
herbivorous extant birds also use gastroliths, their presence
does not = herbivory. This is interesting in view of what
some of us have been saying about possible omnivory in
*'Anatomy is not destiny'
Gardner et al's suggestion that presence of gastroliths in
_Caudipteryx_ indicates myrmecophagy (based on
comparison with pangolins, aardwolves etc which swallow
sand/grit) is faulty because it's clear that non-
myrmecophagous taxa also have gastroliths. Plus, clear to
anyone if they've been following the discussion about ant-
/termite-eating in alvarezsaurids is that myrmecophagous
species have a bunch of skeletal specialisations not seen in
non-myrmecophages, and these aren't present in
caudipterids. The flip side is that the presence of
myrmecophagous specialisations do not consign their owner
just to a diet of ants/termites seeing as _Myrmecophaga_
can eat catfood and _Dasypus_ is a generalist in parts of its
range. Now if only Nick Longrich would publish that
Here are some rumours that may be of interest to some.
Some more dinosaurologically oriented than others...
-- Some time around May 18th the Australian Museum is
apparently set to host a press conference at which they will
unveil some news regarding thylacines. Understandably
rumours are flying round that a live/recently dead/cloned (!)
one has turned up.. we'll see.
-- A megamouth shark washed up on the coast of South
Africa some time within the last two weeks. This must be #
14 or so, and I think it's the 4th specimen from the Atlantic.
-- We have what appears to be a new genus of tapejarid with
a(nother) novel crest morphology here at UOP.
-- W. H. Bensted's notebook has recently been obtained by
Maidstone Museum: sigh, more revisionist history on
Mantell/_Iguanodon_ to deal with... seriously, Martin
Simpson and I are working on this at the moment. It is
looking like pretty much everything written about Mantell
and the early discovery of _Iguanodon_ is in some way
wrong. Certainly Bensted's contribution to the history of the
'Mantel piece' is going to be substantially revised.
-- A new small theropod specimen has been discovered on
the Isle of Wight and is being hailed as a possible
_Calamosaurus_. It appears not to overlap with the holotype
of this taxon though (cervical vertebrae) so this is not
demonstrable. Is being kept at the Dinosaur Farm Museum,
though don't know what they're doing with it.
-- Sadly I was unable to announce on DML the Crystal
Palace Seminar which took place on Jan 4th this year.
Speakers included David Norman, Deborah Cadbury and
Hugh Torrens. The grounds of Crystal Palace have had a
major revamping and the models have been restored and
repaired. The two lost pterodactyls (apparently destroyed
while the site was an army barracks) are now back in their
rightful place and the water level has been lowered so that
the ichthyosaurs, plesiosaurs and teleosaurs can be seen in
their entireity. I was shown a photo last week which
revealed that, to my surprise, the phalanges are visible on
the outside (dorsal/external surface) of the ichthyosaur
flippers. I think the idea here is to represent these bones as
if seen in x-ray, much as the sclerotic ossicles are also
visible on the outside of the eyeballs. This may have been a
common technique used at this time as on Monday I was
shown a cast Loggerhead turtle juvenile where the same
thing has been done, viz, the phalanges were shown in relief
on the outside of the flippers. Crystal Palace is also having
various of the never-completed models made from the
original plans. These include snakes, a mammoth, moa, a
dodo and assorted cats and camels etc. My response on
hearing all of this was "Gosh", or words to that effect (to
paraphrase Trevor Beebee).
I noted a brief discussion on the list about sprawling posture
in monotremes. Try these refs...
Lewis, O. J. 1963. The monotreme cruro-pedal flexor
musculature. _Journal of Anatomy_ 97, 55-63.
Jenkins, F. A. 1970. Limb movements in a monotreme
(_Tachyglossus aculeatus_): a cineradiographic analysis.
_Science_ 168, 1473-1475.
Jenkins, F. A. 1973. The functional anatomy and evolution
of the mammalian humero-ulnar articulation. _The
American Journal of Anatomy_ 137, 281-298.
Pridmore, P. A. 1985. Terrestrial locomotion in monotremes
(Mammalia: Monotremata). _Journal of Zoology_ 205, 53-
There is more recent stuff but don't have it to hand.
Basically, monotremes do 'sprawl' but not in the same
fashion as lepidosaurs (contra Bakker and lots of other
workers) and it seems that this was true of most basal
mammals (or mammaliaforms). Recent papers by Luo et al
and Sereno and McKenna on symmetrodonts and
multituberculates cover this argument in detail - there is
School of Earth & Environmental Sciences
University of Portsmouth
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PO1 3QL www.palaeobiology.co.uk