Re: Parrots

[fredericus ruhe <fredruhe@xs4all.nl>]

At 23:43 23-12-2001 +0100, you wrote:
>> 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.)
>



I used the word herpetologists because not only dinosaurs, but also turtles
and possibly other, maybe even unknown groups of animals might fit the
description, it looked to me a better word to use then dinosaurologists...:-)

Further more I don't think it's a wise thing to do to refere a single
element from the cretaceous to an extant order of birds.
The early tertiary record of birds clearly shows there are a lot of mozaics
around and most early tertiary fossils that are asigned to modern families
are isolated elements, and only a few complete skeletons are asigned to
modern families, like an ibis (Rhynchaeites messelensis Wittich, 1898.) and
a Swift (Scaniacypselus szarskii (Peters, 1985).) from Messel.
So why asign an isolated cretaceous element to the loriids as it isn't even
certain it's avian?
There is also another consideration not to accept this record as loriid: it
extends the record for Psittaciformes with about 20 million years. A thing,
not wise to do on such poor evidence.

Fred