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

RE: Dino-Tick/Mother of all Ticks



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Ken Kinman
>
>
>      As I noted in my other posting last night, ticks were
> probably around
> long before the Upper Cretaceous (how much earlier is certainly
> debatable),
> and they probably had a nearly worldwide distribution by that
> time (although
> tick origins probably were in Gondwanaland).

Incidentally, what is the evidence for this?  If it is simply a matter of
the oldest tick fossils being found in Gondwana, then that isn't very
powerful evidence.  After all, the tick fossil record sucks (sorry, sorry,
had to get that in there somewhere).

Even if they did have a Gondwana origin, that may have been a pre-Pangaea
Gondwanan origin (Gondwana being one of the more stable landmasses in Earth
History, hanging together as a unit from the Pan-African Orogeny of the
Proterozoic into the Cretaceous).  As you mentioned, ticks may have
originated back in the mid-Paleozoic, so they would have had opportunity in
the Triassic to disperse to every corner of Pangaea prior to its break-up.

> There were probably lots of
> ticks in North America by that time, and there doesn't seem to be
> any good
> reason to assume this tick fed on any particular kind of bird, much less
> that a migratory bird carried it from South America to New Jersey.  This
> tick is a rare find, but to suggest (as this report does) that ticks were
> rare in North America in the Upper Cretaceous doesn't make any
> sense to me.

Nor me.  This smacks of an over-literalist reading of the fossil record (a
la the ABSRB "temporal gap") that doesn't take into account taphonomy and
other aspects of the vagaries of preservation.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796