For the first time, fossilized mammal blood, probably from a 20 to 30 million-year-old monkey, has been found in amber. Ok, it's not quite Jurassic Park, but Oligocene Park would probably be safer. In the meantime, we're learning about the evolution of parasites, and maybe something about primate development as well.
Emeritus Professor George Poinar, who proposed the idea of resurrecting extinct creatures from DNA in amber, has produced some astonishing discoveries lately, including insects trapped in amber that look nothing like those we see today. This find, however, is a fairly ordinary Ambylomma tick from a tropical rainforest in the Dominican Republic.
The significance lies in the fact that shortly before it died the tick had been feeding and so was engorged with blood. It had two holes on its back, through which this blood was escaping when it became sealed in tree sap, which subsequently turned to amber.
“These two tiny holes indicate that something picked a tick off the mammal it was feeding on, puncturing it in the process and dropping it immediately into tree sap,” Poinar said in a statement.
The discovery has been announced in the Journal of Medical Entomology, where Poinar notes that, besides preserving the monkey blood in extraordinary detail, the amber also captured parasites of the order Piroplasmida, probably from the Babesiidae family.
One member of this family, B microti, causes the malaria-like disease babesiosis in humans, while Texas cattle fever is caused by a related species. “Fortunately, the parasites were different enough in texture and density from the erythrocytes that the sugars, terpines, and other components in the resin made them as conspicuous as if they had been stained,” the paper notes, with the parasites looking darker than the rest of the blood. The parasites are found in both the gut cells and body cavity of the tick, confirming that, then as now, this is how they were transmitted.
“The life forms we find in amber can reveal so much about the history and evolution of diseases we still struggle with today,” Poinar said. “This parasite, for instance, was clearly around millions of years before humans, and appears to have evolved alongside primates, among other hosts.”
Amblyomma ticks are common in Dominican amber and are known to feed on mammals. The DNA of the mammalian host has not been extracted for definitive identification, but the size of the red blood cells match those of canines or primates. The location is consistent with a tree-dwelling monkey, and the tick's holes look like they were have formed by the fingers of another monkey doing some helpful grooming.
Fossilized 20 to 30-million-year-old red blood cells, some of them infected by parasites. Oregon State University