Re: K-T Theories

[Tom Holtz <tholtz@geochange.er.usgs.gov>]

>I went to Dr. Bakker's lecture last Friday here in Portland, Or.  He promotes
>the disease theory of the K-T boundary.  I still don't find it reasonable, and
>would like to hear from someone who either promotes the theory or at least
>understands it.  My problem with the theory is two-fold.  First, there is the
>issue of spreading the disease.  There are three continental islands where the
>die-off is, presumable, simultaneous with the rest of the land masses, namely
>Australia, India, and Antartica.  How is the simultaneaty of the die-off
>believed to have occurred.
>The second part is the vastness of Dinosauria.  I don't recall whether this
>is a sub-class or a super-order, or what.  The point is that there are many
>different species of dinosaur alive.  It would be hard to imagine a disease
>that affects all mammals, even less so given that it would be fatal and spread
>rapidly across the world (without jet travel! :-) ).
>
>Comments?

Australia and Antarctica were the same continental mass at this time.
Little is known of terminal Cretaceous dinosaur faunas from either.

But, you're right - there are no known cases of mass trans-familial
extinctions that I can think of off hand.  Even though the rinderpest tore
through antelope populations in southern Africa, there wasn't a mass
extinction of this group, much less elephants, lions, aardvarks, or humans
(which all diverged from a common ancestor with antelopes much more closely
in time (~70 million years) than had the latest Cretaceous dinosaurs (>160
million years divergence between theropods, sauropods, and
ornithischians)).

As for how it was supposed to have occurred, your best bet would have to
been asking Bakker.  He is one of the few (if not the sole) supporter of
this hypothesis.

>I have a second question - easier...
>What is the plural of archaeopterix?

When talking about the genus, there is no proper plural of Archaeopteryx,
just as there are no formal plurals of any taxonomic name.  If you use the
name as a "common name" (i.e., like using "hippopotamus" for an individual
of the genus Hippopotamus), the plural would be archaeopteryges.

My preference would be "several individuals of the genus Archaeopteryx".

(Useless taxonomic trivia of the day:  the plural of "sphinx" is "sphinges").

                                
Thomas R. Holtz, Jr.                                   
tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile                  Phone:      703-648-5280
U.S. Geological Survey                                FAX:      703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.