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

Re: naming nodes



Should we transfer this thread to the PhyloCode mailing list?

> It's like I said, only worse. Not only will every node eventually be
named,
> but they will be given >several different names<! Right down the garden
path,
> ladies and gentlemen. PhyloCode, schmylocode.

Wait a minute. PhyloCode is NOT INVOLVED HERE. From the paper (*bold*
_italics_):

<<A diphyletic origin and early vicariant evolution of mammals with
tribosphenic dentitions is consistent with the well-documented provincialism
of mammals in the Mesozoic of South America, which (before the latest
Cretaceous) includes highly distinctive, endemic taxa related to Jurassic
forms of northern continents. The known record suggests that boreosphenidans
and their subgroups were largely or wholly confined to northern continents
during much of their Mesozoic history, until a later dispersal of marsupials
and placentals into South America and other southern continents occurred
during the Late Cretaceous/Early Tertiary.

*Systematic paleontology*
Class Mammalia Linneaus 1758
Subclass Holotheria Wible _et al._ 1995 (ref. 24)
Infraclass Australosphenida nov.
(Include Monotremata; Ausktribosphenida; and _Ambondro_). [This is not a
node-based or any definition, even though it can very easily be rephrased
into one.]
*Etymology.* [...]
*Diagnosis.* Holotherians with tribosphenic molars; differ from
boreosphenidans in having [...]; differ from _Shuotherium_ [...]; and differ
from boreosphenidans (including extant therians) by primitive retention, at
least in _Ausktribosphenos_, of the postdentary trough on the dentary (also
see Supplementary Information).
*Distribution.* Middle Jurassic of Madagascar; Early Cretaceous to recent of
Australian region; Paleocene of South America. The oldest australosphenidan
is _Ambondro_ from the Middle Jurassic of Madagascar.
Infraclass Boreosphenida, nov.
(include Tribosphenida McKenna, 1975)
*Etymology.* From _boreas_ (Latin [wrong, Greek!], meaning northern wind)
[...]; meaning Tribosphenida of the northern continents.
*Revised diagnosis*. Differ from [...]
*Distribution.* Restricted to the Northern Hemisphere during the Early
Cretaceous; present in latest Cretaceous of South America, India [that's
news to me] and northern continets; Tertiary to recent of the world. The
oldest boreosphenidans are Berriasian in age.>>

Boreosphenida includes, among others (the cladogram shows _Kielantherium_),
Metatheria and Eutheria, which include the crown-groups Marsupialia and
Placentalia, respectively. Marsupials are in no way of southern origin.

You see, this is ICZN: Names above the rank of superfamily are always how
anyone likes it best, no priority (unlike PhyloCode). The authors felt that
Tribosphenida was referring to (or implying) everything with tribosphenic
molars, but this has evolved twice (once in the north, once -- much
earlier -- in the south), so the authors coined more appropriate names. BTW,
they don't write whether Boreosphenida is the same as old Tribosphenida or
whether it contains outgroups of it (though they surely mean the former).

BTW, (Australosphenida + _Shuotherium_ [from the Middle -- Late Jurassic of
England and China]) is very basal, Holotheria excludes only _Sinoconodon_,
_Morganucodon_, _Megazostrodon_, _Dinnetherium_ (what's this?) and
_Kuehneotherium_ in this cladogram, even Triconodonta is closer to Boreo-
than (to) Australosphenida.

The cladogram includes _Erinaceus_ -- in Eutheria, far away from
_Ausktribosphenos_. So it is not a hedgehog or any placental.
Tritylodontids, _Obdurodon_, _Ornithorhynchus_, multituberculates and
_Vincelestes_ are included only in a cladogram in the Supplementary
Information (haven't yet looked there). The cladogram stays stable.

LK South American ( + Indian + Malagasy) endemism -- to put some list
relevance into this post :-) -- is reflected in dinosaurs: Abelisauria,
basal iguanodontians...
There is an SVP meeting abstract (2000) that identifies an "ungulate" from
the Paleocene of Argentina as the last surviving dryolestoid :-o ;
Gondwanatheria (a few gnawing teeth from LK + Paleocene of the region) may
belong into Australosphenida, IMHO.

How the modern fauna is impoverished... :.-(