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Re: dwarf tyrannosaurus
From: "Considine, Blaise" <BPC.APA@email.apa.org>
> If nanotyrannus is a dwarf species of tyrannosaurus, why would it need to
> be named T. lancensis?
Because that is the species name it was first given, and priority
rules *seperately* at the genus and species levels. Thus, even when
placed into a new genus, a species retains its original species name.
Since the species was described *many* years ago as Gorgosaurus
lancensis, the name is probalby going to remain lancensis.
[Bakker merely erected a new genus, Nanotyrannus, for this previously
described species - if it turns out to be a species of Tyrannosaurus,
then the genus Nanotyrannus becomes a junior synonym of Tyrnnosaurus].
> Is there already a dwarf species named?
No, there are only two species of Tyrannosaurus at this time,
T. rex and T. bataar. Both are very large.
> And, if
> I've been following this naming thread properly, wouldn't nanotyrannus
Not if it is held to be a species of Tyrannosaurus. It only sticks
as long as the species is held to be in a seperate genus.
And, since size is considered to be a very *minor* feature in
taxonomy, a species that differs *only* in size from some other
species simply does *not* belong in a seperate genus.
But this all depends on the lack of autapomorphies in G. lancensis
other than minor ones like size or the shape of the skull ridges.
[Since the skull ridges in tyrannosaurids are species recognition
characters, they are expected to change rapidly and noticably
between any two species].
Note, Tyrannosaurus is not the only possiblity here. Depending
on its actual phylogenetic position, and on the acceptance of
Gorgosaurus again as a genus, the species might be placed in
Albertosaurus or even returned to its original position in
I just suggested Tyrannosaurus since Dr. Holtz cited one
expert as claiming it had no significant difference from
The peace of God be with you.