[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Crown Mammals with Multituberculates?
> "Morphological and physiological differences and paleontological data
> suggest the independent origin of the Prototheria and the Theria. The
> Prototheria gave rise to the most specialized groups of Mesozoic
> The reasons for this are discussed.
Here they are:
Hm... 14 terminal taxa (3 of them para- or polyphyletic), 11 characters (6
of them autapomorphic and therefore uninformative), but no polytomies,
despite 7 unsupported nodes. (If I counted correctly.) And several
interesting taxa are missing. Something is rotten in the state of
> An important role in the evolutionary
> fate of these subclasses was played by the structural difference in the
> region of the middle ear, since it influenced the structure of the
Ah, the good old times. Phylogeny based on one single character complex,
ignoring all others. Right?
> The development of a perfect placental pattern in the therian
> stem at the end of the Cretaceous was a key character determining the
> fate of mammals. This gave rise to changes in the central nervous system
> and provided for the domination of the Placentalia in the Cenozoic."
> The paper proposes the following phylogeny on the basis of some shared
> and rather plesiomoprhic conditions outlined in the abstract:
That's supposed to be a terminal taxon, *Procynosuchus*, right?
> | `--+--Chiniquodontidae
> | `-a-+--Kuehneotheria
*Kuehneotherium* and what else? *Woutersia*?
What is the a?
> | `--+-4,7,8-Symmetrodonta
> | `-7-+-5,8-Eupantotheria
Less heavily paraphyletic, but still impressive.
What, all of them? Diademodontidae, Traversodontidae and Tritylodontidae?
> | `--+-1-Morganucodontia
> | `-4-Triconodonta
And their synapomorphies? Character 1 maybe?
That's normally just Haramiyida + Multituberculata.
> | `-7,9-Multituberculata
Triconodonts sensu strictissimo, Multis and monotremes have a single jaw
joint, *Kueneotherium*, docodonts and haramiyids retain a double one like
*Morganucodon*. Chiniquodontids and "gomphodonts" retain a single jaw
joint, the "reptilian" one, of course. Makes 2 gains of the "mammalian"
joint and 4 losses of the "reptilian" one.
> Numbers refer to apomorphies, as in the text and figure 7 of the
> 1) tricuspid cheek teeth;
> 2) multituberculate cheek teeth;
Pretty undeniable, but this is the only character complex that keeps
Allotheria together... against all other evidence I know of.
> 5) tribosphenid tooth crowns;
Also in monotremes.
> 11) abrupt increase in brain size.
*Eomaia* has such a bigger brain than *Deltatheridium*? :-S
> A [...] competantly [sic] done paper.
+++ GMX - Mail, Messaging & more http://www.gmx.net +++
Bitte lächeln! Fotogalerie online mit GMX ohne eigene Homepage!