Oldest Mammalian Blood Cells Found in Tick Stuck in Amber

Somewhere between 15 and 45 million years old, give or take a million years or so.

engorged nymphal Amblyomma tick
George Poinar, Jr

Scientists have discovered what appears to be the oldest known mammalian blood cells, clocking in at an estimated 15 to 45 million years old.

Described in a a paper published in the Journal of Medical Entomology by George Poinar Jr., a professor at Oregon State University, the cells tell a story older than mankind: one of cleaning and self-preservation. Between 15 and 45 million years ago, two primates were engaged in the societal act of checking each other for ticks. Having found one, one tossed it off the other's back, accidentally sending it into tree sap. Some several million years later, here we are.

"Fortunately," Poinar says, "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." Every aspect of the tick was available to be studied, which allowed Poinar and his team to identify even the various growth stages of life the tick went through before meeting its untimely demise in the amber.

Found in the Dominican Republic, there are three possible options for where the tick and its stolen blood cells were once residing: Poinar has narrowed it down to canines, rabbits, or primates. But the find speaks to precisely how old mammals are as animals, and the primal urges that have continued in a straight line precisely to this era.

Source: Discover

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