The oldest known amber-preserved fly and mites have just been discovered in northeastern Italy.
The specimens date to 230 million years ago, a time that interestingly coincides with the appearance of the world's first dinosaurs.
The mites didn't bite into dinosaurs, which was good news for the dinos, perhaps, but bad news for those hoping for some dino DNA.
The mites represent two new species, named Triasacarus fedelei and Ampezzoa triassica. They are the
oldest fossils in an extremely specialized group called Eriophyoidea that
has about 3,500 living species, all of which feed on plants and sometimes
form abnormal growth called galls. The ancient gall mites are
surprisingly similar to ones seen today.
"You
would think that by going back to the Triassic you'd find a transitional
form of gall mite, but no," said David Grimaldi, a curator in the American Museum of
Natural History’s Division of Invertebrate Zoology, in a press release. "Even 230 million years ago,
all of the distinguishing features of this family were there — a long,
segmented body; only two pairs of legs instead of the usual four found in
mites; unique feather claws, and mouthparts."
The
ancient mites likely fed on the leaves of the tree that ultimately
preserved them, a conifer in the extinct family Cheirolepidiaceae. The mites are so old that they pre-date the existence of flowering plants.
"We
now know that gall mites are very adaptable," Grimaldi said. "When
flowering plants entered the scene, these mites shifted their feeding
habits, and today, only 3 percent of the species live on conifers. This
shows how gall mites tracked plants in time and evolved with their
hosts."
As for the fly, the researchers aren't sure what kind it was. The amber pieces are very small, so when the invertebrates kicked the bucket by drowning in tree resin, they were entombed in mere drops of the stuff.
"Amber
is an extremely valuable tool for paleontologists because it preserves
specimens with microscopic fidelity, allowing uniquely accurate estimates
of the amount of evolutionary change over millions of years," Grimaldi, who is a world authority
on amber and fossil arthropods, said.
He and his colleagues hope to find more Triassic Era amber inclusions.
"There
was a huge change in the flora and fauna in the Triassic because it was
right after one of the most profound mass extinctions in history, at the
end of the Permian," Grimaldi concluded. "It's an important time to study if
you want to know how life evolved."
The find was reported in the latest issue of PNAS.
(Image: American Museum of Natural History)
