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)