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Re: Diatryma and mammals!




On Sat, 1 Aug 1998, Ronald Orenstein wrote:

> Feduccia, in citing Andors in The Origin and Evolution of Birds notes that
> "its
> habitat, as deduced from depositional environments, was coastal lowlands and
> alluvial floodplains".

Andors in full (Andors, A.V. Reappraisal of the Eocene groundbird
_Diatryma_ in Campbell, K.E. (ed.) Papers in Avian Paleontology
-Honoring Pierce Brodkorb #36 Science series Nat. Hist. Mus. of LA County)
says:
" Depositional environments and associated floras and faunas indicate that
the D. were inhabiatants of coastal lowlands and alluvial floodplains
 (Andors 1988) Although eurytropic, diatrymids may have been primarily
paludal (I can't find that word in any dictionary I own), preffering
humid, well-vegetated back-swamps that were doomed to contract once the
period of relative tropicality that characterized the earlly Tertiary came
to a close.  Their presumed closest relatives (Andors 1988) the
Neotropical screamers, exhibit similar preferences for marshy habitats.
the persistence of suitable habitats in northern S. America probably
explains the survival of the screamers as marginal relicts."

And later: "...North American populations may have been extirpated by
regional elimination of backswamp plant communities associated with
secular cooling and drainage reversal brought about by the Laramide
orogeny...In Europe, diatrymids lingered on somewhat longer, until the end
of the Middle Eocene, when their lake-margin refugia were finallt
eliminated by continued climatic deterioration..."