Hmmm.......modern fish have parasites.
I just hate to consider the feeding abilities of a Mesozoic parasite.
That just sucks........
Cheers, Marilyn At 6:18 PM +0000 3/30/01, Ken Kinman wrote:
Very well put. I would only clarify that I would characterise tick origins as probably late-Paleozoic (probably not mid-Paleozoic, even though mites are known from the Devonian).
I just heard back from Hans Klompen this morning, and in all fairness, his suggestion was that the genus Carios had a South American origin. He thinks ticks as a group originated in Australia. So the reporter apparently took some of his suggestions out of context. But I think Hans will regret having suggested that the tick hitched a ride from South America to New Jersey.
I think Klompen is probably correct that ticks did originate in Gondwanaland (although he is probably really sticking his neck out in specifying Australia, especially considering what the vertebrate people are now learning about the hazards of overextrapolating from biogeographic data). But I still doubt his belief that ticks arose in the middle of the Mesozoic. I think the Permian is a better bet, and that Permian reptiles (which in my traditionalist classification would include pelycosaurs and therapsids) were biting and scratching at primitive tick parasites well before the Mesozoic began. We obviously don't have enough information to know for sure (with only one Mesozoic tick, we have only barely begun "scratching" the surface------->pun intended).
P.S. The fossil record of fleas also "sucks", and I think the earliest known flea is Eocene. I expect we will eventually find Mesozoic fleas as well, but I would be hesitant to bet that they existed back in the Permian. Pelycosaurs (at least the Permian forms) may well have had to deal with ticks, but suspect that only their Mesozoic & Cenozoic descendants had to deal with fleas as well (eventually crossing over to some birds). Ticks on dinosaurs seem very, very likely, but not sure that fleas would have ever bothered them much. I am suddenly having a strong urge to scratch, so will leave it at that.
*********************************************************From: "Thomas R. Holtz, Jr." <email@example.com> To: <firstname.lastname@example.org>, <email@example.com> CC: <firstname.lastname@example.org> Subject: RE: Dino-Tick/Mother of all Ticks Date: Fri, 30 Mar 2001 10:32:09 -0500
From: email@example.com [mailto:firstname.lastname@example.org]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: email@example.com Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796_________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com