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With re to (my post saying that) pangolins evolved as eaters of leaf-cutter
ants, Ronald Orenstein writes..
> Where did this come from? Pangolins are strictly old world, and leafcutter
> (attine) ants, to my knowledge, are strictly new world. I know pangolins
> have long tongues, but surely not as long as that.....
Pangolins are not (sorry) strictly Old World: in 1970 Emry described an
Oligocene pangolin from North America. As for the ants, well, they're in
Disney's 'Lion King', and that's set in Africa.. just kidding.
The funny thing about _Eomanis waldi_ Storch 1978, the Messel
pangolin, is that, despite having the thin, edentulous (and relatively
immobile) jaws of modern pangolins, stomach contents (known from _all
five specimens_) reveal that it had ingested plant material. This was
totally unexpected, as in every other detail it would appear that
_Eomanis_ was myrmecophagous, like extant manids. Only one _Eomanis_
specimen has insect remains amongst the stomach contents. Modern
pangolins swallow sand to break up their insect prey, and that this
was found amongst the stomach contents of _Eomanis_ further suggested
that the stomach contents were not, say, debris that had just drifted
I should have emphasised that the thing about eating leaf-cutter ants
was a hypothesis. Storch and Richter (1992) have suggested that
_Eomanis_, being herbivorous, 'stole' leaf segments cut by ants. It
accidentally (?) ingested some ants too however, and was, in practise,
myrmecophagous. This does not explain the manid morphology, which,
already in Eomanis_, appears adapted for myrmecophagy... it's a
chicken - egg situation (i.e. which came first, the ant- eating
behaviour or the morphology).
As for the ants, as far as I can tell, the only ones known from Messel
are huge volant sexual phases of formicid species (wingspans up to 16
cm!). Perhaps leaf- cutters were more widespread in the Eocene, or
perhaps ants other than attines were leaf-cutters back then. Given the
ridiculous extent of known parallelisms amongst hymenopteran taxa, I
would expect the latter.
EMRY, R.J. 1970. A North American Oligocene pangolin and other additions to the
Pholidota. _Bull. Amer. Mus. Mat. Hist._ 142: 455-510
STORCH, G. 1978. Ein Scuppentier aus der Grube Messel-zur Palaobiologie eines
mitteleozanen Maniden. _Natur u. Museum_ 108: 301-307
---------. 1978. _Eomanis waldi_, ein Schuppentier aus dem Mittel-Eozan der
'Grube Messel' bei Darmstadt (Mammalia: Pholidota). _Senckenbergiana Lethaea_
STORCH, G. and RICHTER, G. 1992. Pangolins: almost unchanged for 50 million
years. IN SCHAAL, S. and ZIEGLER, W. _Messel: An insight into the history of
life and of the Earth_. Clarendon Press (Oxford): 203-207
"It's just been revoked"