An international team of scientists has discovered the oldest record of arthropods -- invertebrate animals that include insects, arachnids, and crustaceans -- preserved in amber. The specimens, one fly and two mites found in millimeter-scale droplets of amber from northeastern Italy, are about 100 million years older than any other amber arthropod ever collected.
"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," said corresponding author David Grimaldi, a curator in the American Museum of Natural History's Division of Invertebrate Zoology and a world authority on amber and fossil arthropods.
Globules of fossilized resin are typically called amber. Amber ranges in age from the Carboniferous (about 340 million years ago) to about 40,000 years ago, and has been produced by myriad plants, from tree ferns to flowering trees, but predominantly by conifers. Even though arthropods are more than 400 million years old, until now, the oldest record of the animals in amber dates to about 130 million years. The newly discovered arthropods break that mold with an age of 230 million years. They are the first arthropods to be found in amber from the Triassic Period.
The amber droplets, most between 2-6 millimeters long, were buried in outcrops high in the Dolomite Alps of northeastern Italy and excavated by Eugenio Ragazzi and Guido Roghi of the University of Padova. About 70,000 of the miniscule droplets were screened for inclusions -- encased animal and plant material -- by a team of German scientists led by Alexander Schmidt, of Georg-August University, Göttingen, resulting in the discovery of the three arthropods. The tiny arthropods were studied by Grimaldi and Evert Lindquist, an expert on gall mites at Agriculture and Agri-Food Canada in Ottawa.
Via Dr. Stefan Gruenwald