Cretaceous tick 'biogeography'
John R. Grehan
jrg13 at PSU.EDU
Tue Apr 17 19:19:09 CDT 2001
With an earlier posting refering to the 'biogeography' of the Cretaceous amber
tick I decided to take a look a the text. I don't know if anyone else on this
list can appreciate the irony of the transition between the way detailed
is presented for characterizing the taxonomy and the speculations about the
global travels of this mite based on nothing more than some kind of faith in
the way things happened.
The authors first quote Klompen et al (1996)to assert that a "combination of
systematic analyses and comparisons of distribution patterns indicated an
origin in the Neotropic region". They don't bother stating what the nature
of this evidence is, whether 'systematic analyses' and 'comparison of
distribution' really indicate such an origin (or more likely read into the
data as a preconceived notion). Once said, it is asserted that this origin
is "presumably" after the isolation of South America so this is 'compatible'
with the proposed timing! Why presumably is never said.
Once the South American center of origin is posited the authors
make it necessary for dispersal across an ocean barrier to North Amnerica.
They then create a whole series of plausible speculations based on
apparently nothing more than an assertion that this is the way things
I happen to find it difficult to see how any of these speculations contain
any more scientific content that a creationist speculating about the location
of the arc (although the latter might actually be more precise in its
methodology). Am I alone in my concern? If others on this list believe the
biogeographic account presented by Klompen and Grimaldi qualify as
'science' I would be interested to see how this is justified. If science, is
it good science? Does anyone care one way or the other anyway?
Evidently the editors and reviewers of the article for the Annals of the
Entomological Society of America thought the speculations were scientific
to have them published.
On the original assertion by Klompen et al 1996 it seems that the genus
originated in the 'New World' because the basal lineages are there. This is
simply an assertion rather than being a derivation of systematics and
comparison of distributions. I've only made a quick reading so far, but I have
not seen reference to the neotropics as such or any comparisons of
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