Stasis classic, from the Eocene, specimen dated from about 44 to 49 mya.
From Nature: News:
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.
From National Geographic:
Dunlop and his colleagues studied the specimen under a microscope and created images of what they saw. The results reveal the mite belongs to a family whose living species are thought to parasitize ants, and the ant is of the species Ctenobethylus goepperti.
Mites are often found living with ants, though scientists don’t know exactly what the mites do to the ants. But the discovery offers a new clue by showing that the phenomenon has occurred for at least 45 million years—much longer than thought.
Here’s the abstract:
Fossil mesostigmatid mites (Acari: Parasitiformes: Mesostigmata) are extremely rare, and specimens from only nine families, including four named species, have been described so far. A new record of Myrmozercon sp. described here from Eocene (ca 44-49 Myr) Baltic amber represents the first-and so far only-fossil example of the derived, extant family Laelapidae. Significantly, modern species of this genus are habitually myrmecophilous and the fossil mite described here is preserved attached to the head of the dolichoderine ant Ctenobethylus goepperti (Mayr, 1868). It thus offers the oldest unequivocal evidence for an ecological association between mesostigmatid mites and social insects in the order Hymenoptera. (paywall)
File under: Earlier than thought
See also:
300 mya Harvester: “The fossil record is proving to be less and less Darwinian as we examine the details.”
and
For daddy longlegs, evolution never happened, it seems
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