Acarina, pycnogonids, Permian ticks?

John Grehan jrg13 at PSU.EDU
Wed Apr 18 07:02:08 CDT 2001

 Therefore I think that there were plenty of ticks in North America
>>during the Cretaceous, and Klompen's hypothesis that the New Jersey tick
>>hitched a ride on a seabird from South America is rather far-fetched.

Far-fetched or not, the hypothesis is not based on any kind of evidence at
Its just a derivation of the presumption that the means of dispersal of ticks
alone is the key to their distribution. As far as I can see there is no
in this kind of biogeography.

, and on the basis of his published
>phylogenies, his geographic hypotheses are consistent with the evidence.

This seems to be circular. From what I have read so far Klompen interprets
the location of the basal lineage as the center of origin, so naturally the
distribution is 'consistent' with the 'evidence'. The presumption here is
that global tick distribuiton can be resolved in terms of an identifiable
center of origin and means of dispersal, with the location of basal lineages
being the predictor of the center of origin. This kind of biogeography has
never been substantiated on an empirical basis (i.e. that the location of
lineages necessarily denote such centers of origin).

None of this criticism is new. It interests me that most biogeography that
continues to be published relies on faith in means of dispersal and centers
of origin regardless of the lack of science involved. In any other subject
such approaches could not be published. It seems that systematics managed
to move beyond the phase of unsubstantiated assertions, but biogeography
for the most part remains in the 19th century, with the ironic result that
many systematists set a high standard for the taxonomic work, and a low one
for biogeography.

John Grehan

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