Fascinating piece in the Science Times today concerning Dr. Gonzalo Giribet and a group of Harvard biologists’ research of the tiny mite harvestman and what it tells us about plate tectonics. Although biogeography informing plate tectonics is nothing new and indeed the concept of continental drift originated with German scientist Alfred Wegner’s observation that similar fossils could be found on now distant continents, the mite harvestman tells a more detailed story.
Steve Gschmeissner/Photo Researcher (left) and Nigel Cattlin/Photo Researchers
(Note: the picture on the right is actually a true spider and not a harvestman. Thanks to Mrs. Tilton for bringing this to our attention and Bug Girl for confirming the grievous error)
A relative of the daddy longlegs, the mite harvestman appears as a mere speck to the human eye. However, the tiny critter has existed in some form or another for hundreds of millions of years and does not disperse well. This means that many different species of harvester mite have remained isolated geographically even when other organisms spread rapidly across and between landmasses “blurring” their histories.
By examining the mite species DNA, the researchers discovered a remarkable correlation between the current pattern of distribution and the makeup of Pangea 255 million years ago. One species of harvester mite found in Florida was not related to other North American species but similar to those found in West Africa. By determining the rate of genetic variation, Dr. Giribet and his team can estimate when landmasses separated from one another providing fascinating detail into an often unclear ancient history.
The New York Times