A blood-engorged nymphal tick of the genus Amblyomma surrounded by fossilized mammalian erythrocytes (red blood cells) has been discovered in a piece of 15-45-million-year-old amber. The discovery is reported March 20 in the online edition of the Journal of Medical Entomology.
Two small holes in the back of the Amblyomma 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 in what is now the Dominican Republic.
“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,” said Oregon State University Professor George Poinar, Jr., author of the study.
“This would be consistent with the grooming behavior of monkeys that we know lived at that time in this region,” he added.
The amber specimen was obtained from mines located in the Cordillera Septentrional of the Dominican Republic.
“Estimated ages range from 15–23 million years, based on foraminifera counts, to 30-45 million years, based on coccoliths,” Prof. Poinar said.
