Re: Parrots

["David Marjanovic" <david.marjanovic@gmx.at>]

> Well?
>
> Let's face facts.
>
> Gerald Mayr & Michael Daniels described _Psittacopes lepidus_* from an
> allmost complete, articulated skeleton from the eocene of Messel. It was a
> parrot that did not have a "parrot-like"beak.
> [...]
> As I have learned from Stidham, he wants to assign his beak to
> Loriidae. Well that's nice, it's based only on nuticient channals. If
> Parrots didn't have a parrot-like beak in the eocene, how could they have
> them in the cretaceous (if they were there at all)?
> [...]
> If Psittacopes is a Parrot, then I think Stidham is wrong in his
> identification, parrots didn't have a parrot-like beak by that time.

I happen to believe these arguments. But...

> If indeed his specimen is a Loriid, we must think again on Psittaciformes,
[...]

Stidham says *Psittacopes* etc. are _sister groups_ to the crown group, so
his LK jaw just drags the split between them and the crown group a bit back
in time. I consider this improbable because it also drags splits within the
crown group that far back and implies a mass survival of a huge diversity of
psittaciforms through the K-T mass extinction. This is not parsimonious,
even though Stidham's morphological analysis is (given the present knowledge
of the fossil record).

> It's also possible Gerald Mayr is wrong, and he misidentified his parrot
> >from Messel that had a beak like a Coliidae.
>
> I don't believe Gerald Mayr was wrong, and I think you hepetologists can
> come up with enough species that can fit Stidham's identification.

"We herpetologists"? Some call themselves dinosaurologists, some call
themselves vertebrate paleontologists, but herpetologists... :-(
Anyway, nobody has yet come up with an answer to the question "if it isn't a
lori, what is it?". It does not appear to be an oviraptorosaur, which have
the most parrot-like beaks of all other theropods. It could belong to an
otherwise unknown group of somehow specialized oviraptorosaurs, or
Enantiornithes, or whatever, but this is pure speculation. On pure
morphology, it is most parsimonious to assign it to Loriidae at present.
IMHO this is a case where cladistic parsimony analyses are of limited use;
it is something like long-branch attraction caused by too many unknown
character states.
        Another such phenomenon occurs when people try to find out a taxon's
position by comparing it with the wrong forms. Think of all the analyses of
bird and near-bird phylogeny which only include Velociraptorinae as an
outgroup -- such analyses will never reveal whether the usual contents of
Dromaeosauridae form a paraphyletic group, nor whether birds are closer to
"enigmosaurs" than to dromaeosaurs, nor the position of *Protarchaeopteryx*.
        (For a long time I thought that considering segnosaurs theropods was
a similar case -- the analyses never included prosauropods to test, so
segnosaurs -- highly derived, long branch -- should come out next to the
group of theropods they shared most convergences with, not at their "true"
position basal to all theropods. Well, then came the first metatarsal of
*Beipiaosaurus* which is different from any prosauropod and convinced me
once I understood the image, and then came HP Mickey Mortimer's experiment
of really entering segnosaurs into a prosauropod analysis.)