[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Greg Paul is right (again); or "Archie's not a birdy"



2011/8/2 Mike Keesey <keesey@gmail.com>:
> On Tue, Aug 2, 2011 at 5:27 PM, Augusto Haro <augustoharo@gmail.com> wrote:
>>
>> As today the stem- and node- based
>> definitions are preferred in phylogenetic parlance, perhaps
>> clumsy-looking new names as "Apexaves" or "Panapexaves" (of course,
>> something with better classical language grammar) can serve for the
>> crown- and stem- based definitions, whereas still bearing
>> reminiscences of the typological traditional names with which they
>> better overlap.
>
> Ugh, why?
>
Just to avoid re-definitions and the possible confusion in the
literature between different meanings of the same name. As with genera
and species in the ICZN.

> Look, there's already a good, well-thought-out solution. Use
> neontological names for crown groups. Do it everywhere in biology.
> Maximize cross-disciplinary understand. Limit unjustified inferences.
>
I know the argument of only inferring non-fossil features for those
taxa that parsimony leads you to unambigously infer them. Do not know
other arguments for this practice. But these non-fossil features are
those of lesser systematic interest for definition, because you do not
know if these are present in fossils or not, and are ambiguous
apomorphies of the Recent crown. One may wonder why would be clearly
ambiguous apomorphies so important in the decision of systematic
definitions (or redefinitions).

2011/8/3 Thomas R. Holtz, Jr. <tholtz@umd.edu>:
>> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
>> On Behalf Of David Marjanovic
>>
>> >  As "Avialae" was originally defined on the basis of apomorphies
>>
>> Oh no, it wasn't. It was defined in some branch-based way
>> that I have forgotten, maybe as everything closer to modern
>> birds than (to) *Deinonychus*.
>
> "...and the name Avialae is applied to Ornithurae plus all extinct 
> maniraptorans that are closer to Ornithurae than they are to
> Deinonychosauria." Gauthier 1986, p. 36, col. 2, para. 3. Archaeopteryx is 
> listed in the included taxa, and he makes clear that
> Archie was the primary source for the diagnosis of the clade, but the 
> definition was a branch-based taxon name (using modern
> terminology).

You both are right, my bad following Wikipedia instead of going to the
sources. Gauthier and de Queiroz (2001, p. 26) say something, however,
which leads to doubt about the original definition:

"The name “Avialae” was defined originally by Gauthier (1986:36) as
referring to “Ornithurae plus all extinct maniraptorans that are
closer to Ornithurae than they are to Deinonychosauria,”which is a
stem-based definition. However, unlike the case for definitions
proposed for names of clades that emerged from his analysis, Gauthier
(1986) did not always provide explicit definitions for his terminal
taxa (e.g., Carnosauria) or use them consistently when he did. Thus,
although Gauthier (1986) defined “Avialae” as the name of a stem-based
clade, he also used it as a name for the Archaeopteryx node (for
example, when listing the synapomorphies [1986:12]) and as an
apomorphy-based name (when referring to avialans as “winged theropods”
[1986:12])."

Ref:

Gauthier, J., & de Queiroz, K. 2001. Feathered dinosaurs, flying
dinosaurs, crown dinosaurs, and the name “Aves”. In "New Perspectives
on the Origin and Early Evolution of Birds: Proceedings of the
International Symposium in Honor of John H. Ostrom".