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PHYTOLITHS



Has anyone ever seen phytoliths on a dinosaur tooth or, fundamentally,
looked for them? I have recently finished reading Ciochon, Olsen and
James' excellent book 'Other Origins - the search for the giant ape in
human prehistory' (Victor Gollancz Ltd, London, 1991,
pp. 262). Inspired by the encounters that occurred in Pleistocene SE
Asia (Vietnam in particular) between the giant hominid
_Gigantopithecus blacki_ and our ancestor _Homo erectus_, the authors
excavated the Lang Trang area to reconstruct the fauna and the
lifestyles of these animals (there is a diorama by John Sibbick in
David Norman's 'Rise of the Vertebrates' featuring most of the mammals
discovered at the Lang Trang sites).

They were surprised to learn, from archaeology student Bob Thompson,
that the minute silica objects (they form within the plant's tissues)
called phytoliths can be left on teeth, and therefore indicate
diet. SEM studies showed bamboo and fruit (from Moraceae) phytoliths
on _Gigantopithecus_ teeth, and here for the first time is proof of
what this animal ate. We now _know_ that _Gigantopithecus_ ate bamboo
and certain fruits. So can this method be applicated widely?

PHYTOLITHS ON DINOSAUR TEETH?

There remains controversy over the diet of some of the herbivorous
dinosaurs.  Though some, like sauropods, didn't chew their food in the
same way as the primates, might it be possible that phytoliths were
left on teeth? It would take examination of a tooth surface by SEM to
find out. Could anyone do this to find out? I imagine there would be a
problem in identifying a Mesozoic phytolith, but perhaps the
morphology of it might indicate what plant it came from.

I would suggest diplodocids as test subjects. Whether they ate conifer
needles or terrestrial ferns remains a matter of opinion. Anthony
Fiorillo has previously looked at tooth microwear to determine
sauropod diet, and found that _Diplodocus_ had little wear compared to
camarasaurs and brachiosaurs. This might mean that _Diplodocus_ ate
high up, well away from abrasive grit found at ground level, or it may
mean that it ate soft terrestrial foliage that grew perhaps only a
metre or two above the ground. Theoretically, phytolith analysis could
remove doubt.

I see problems in the idea, as mentioned above, but on learning of the
implications of phytolith discovery, I wondered if it might be a subject worth
nominating for investigation. If we simply don't know enough about Mesozoic
botany and/or phytolith identification for there to be any success, then it's
back to the drawing board. Likewise if archosaur teeth are simply useless at
retaining phytoliths. But it's an idea...

DARREN NAISH