A new paper by Emeritus Professor George Poinar, Jr. published in the Journal of Medical Entomology adds to the list.
Science Daily attempts to reconstruct what happened:
“Two monkeys grooming each other about 20-30 million years ago may have helped produce a remarkable new find - the first fossilized red blood cells from a mammal, preserved so perfectly in amber that they appear to have been prepared for display in a laboratory.”
Discovered in the Dominican Republic, the amber also held a tick and the parasite Babesia microti that still makes life uncomfortable for humans and animals.
“Two small holes in the back of a blood-engorged tick, which allowed blood to ooze out just as the tick became stuck in tree sap that later fossilized into amber, provide a brief glimpse of life in a tropical jungle millions of years ago.”