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

Re: birds and/or/with dino's

On Tue, Sep 15, 2009 at 8:31 PM, Tim Williams <tijawi@yahoo.com> wrote:
> In the case of Cetartiodactyla, however, the name denotes a novel 
> phylogenetic hypothesis: that whales (Cetacea) evolved within the 
> Artiodactyla. ÂSo I think that might have been the intent behind the name 
> Cetartiodactyla: to highlight a novel phylogenetic position for whales w.r.t 
> "traditional" artiodactyls.

I have to agree with Mike Taylor -- a phylogenetic hypothesis should
ideally not be part of a name.

> Having said that, not all paraphyletic groups survived the changeover: 
> Protozoa, Apterygota, Labyrinthodontia, Proteutheria, Thecodontia (though 
> somebody once tried), Condylarthra, etc. ÂBut these tended to be used as 
> wastebasket groups, so they're probably best left behind.

Isn't Condylarthra polyphyletic? (Or is that still being worked out?)
Pretty sure Protozoa and Proteutheria are, too. The rest more or less
correspond to clades which already had other names: Insecta (or
Hexapoda), Tetrapoda (sensu lato, ="Apo-Tetrapoda"), Archosauria (or,
really, Archosauromorpha/"pan-Archosauria"--although this was
paraphyletic originally, too, but it referred to a taxon much closer
to the clade than Thecodontia).

> As with Cetartiodactyla, coming up with a new name for a traditional dinosaur 
> + bird clade (like "Dinoaves") would also have given recognition to this 
> being a paradigm shift - in the sense that it overturned a widespread (and 
> erroneous) belief that birds and dinosaurs had separate origins.

Incidentally, "Dinoaves" was already used by Bakker (Heresies) for a
clade similar in content to Tetanurae or Neotetanurae (=Avetheropoda).

> I also think Cetartiodactyla is unnecessary - especially given that recent 
> morphology-based phylogenetic analyses (e.g., Thewissen et al., 2007) recover 
> whales (Cetacea) outside crown-clade Artiodactyla.

Well, in that case it *would* be useful, as a name for the clade
includng Cetacea and Artiodactyla.

Something like this could work:
Artiodactyla := Clade(Sus scrofa + Camelus dromedarius + Bos taurus)
Cetartiodactyla := Clade(Balaena mysticetus + Sus scrofa + Camelus
dromedarius + Bos taurus)

Then give the former precedence if they turn out to be
heterodefinitional synonyms. (Mmm, cinnamon.)

T. Michael Keesey
Technical Consultant and Developer, Internet Technologies
Glendale, California