This ancient ant and its parasitic companion became locked together in amber about 44 to 49 million years ago. It's the oldest known example of a mite attached to its victim.
As for this latest find, it's only the second known example of a fossilized mite attached to its host. Nature News explains:
The 0.7-millimetre-long mite and its victim are preserved in amber, which is fossilized tree resin. The mite appears to be firmly attached to the ant's head — a behaviour also seen in modern parasitic mites of the genus Varroa, which are often mentioned as possible culprits in the sudden collapse of honeybee colonies.
Although it is difficult to say for sure, the ancient mite was probably a parasite, too, says Jason Dunlop, an arachnologist at the Leibniz Institute for Evolution and Biodiversity Science in Berlin. "The amber mite looks very similar to modern mites, so we presume it had a similar mode of life and was parasitizing the ant rather than attacking it directly," he says.
In a paper published on 10 September in Biology Letters, Dunlop and his collaborators identify the mite as belonging to the genus Myrmozercon, which includes numerous species still alive today. An air bubble trapped between the two invertebrates hides some anatomical features, making it hard to identify the exact species. Mites are arachnids, a class of eight-legged arthropods that includes spiders and scorpions.
More at Nature News.