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Re: Missing link feather fossils



> structure? I wonder how they compare to the feathers
> of ratites. 

Many ratite feathers have an aftershaft, that is, they
have a small secondary feather attached to the bottom
part. But some don't. Still, it would be worthwhile to
compare them to these, as well as to other Cretaceous
non-pennaceous feathers.

It is almost certainly impossible tha they are ratite
feathers though. Finding a ratite from there and then
is almost as unlikely as finding a tarsometatarsus of
a passeriform bird in the Mesozoic (the latter is if
the present consensus is any good about impossible.
The former cannot be ruled out but is highly, highly
unlikely).

The St Bathan's fauna (Journal of Systematic
Palaeontology 5 (1): 1–39
doi:10.1017/S1477201906001957) includes what seems to
be moa remains, but it is Early/Mid-Miocene. This ties
in with ostrich fossils and _Emuarius_ suiggesting
that at the end of the Paleogene, there were ratites
was we know them today, both by lineage and by
morphology.

_Diogenornis_ is the only (and tentative) indication
at present that the ratite morphotype evolved in the
Paleogene, possibly even the latest Cretaceous.

But all these are southern hemisphere finds. The
northern hemisphere apparently had other giant birds
in the Paleogene (diatrymas and _Eremopezus_ for
example - the latter might have been a superficially
ostrich-like storkish critter, perhaps). Laurasian
ratites seem to have been rather tinamou-like til
ostriches arrived in the Neogene (not sure, but it's
the most satisfying hypothesis).

Given that diatrymas are generally held to be
Galloanseres nowadays, they are a possible candidate.
100 Ma seems a bit much though; all we *can* say is
that Gastornithiformes must have been a distinct
lineage about 70 mya (qua _Vegavis_), but the present
scenario would make it very unlikely that they were
distinct *and* had arrived at their morphotype 100 mya
already.

_Gargantuavis_ is sufficiently close in time, place
and lineage to make an older relative of it the most
promising *avian* candidate. Its lineage is unknown
but it seems not to have been a modern bird (in the
strict sense, i.e. Neornithes). If this is correct, it
makes for a comfortable to very comfortable fit
(depending on whether it was enantiornithine or much
closer to modern birds).

IONO whether the supposed diatryma feathers were
verified. At least part of it seems to have been plant
fibers.


Regards,

Eike




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