Sunday, 2 September 2012

The Oldest Amber Time Machine On The Planet

Amber is an incredibly beautiful substance. Usually the pieces are a rich yellow, but can be very different with a full and diverse range of colours, stretching from almost white to a polished mahogany. Yet the amber you see in jewelry stores has an amazing story behind it.

Some of the colours amber can be
The solid, almost glassy amber was once a thick, fluid resin leaked from ancient trees in long lost forests, hundreds of millions of years ago. As globules made contact with the air, they hardened into chunks of resin, and were buried over millennia. Since the birth of civilization amber was mined from surrounding rock across the Earth, including the Dominican Republic, the Baltic Sea and the Konigsberg coastline in Russia.

Raw amber is similar in colour and texture to pieces of hard toffee or caramel. In workshops, it is ground and polished. Colourful, flawless pieces are eagerly sought. Yet once in a while, something unexpected turns up. For as the amber is polished on a lathe, the edge of a wing case or the leg of a trapped fly is revealed.

Creatures encased by the resin, were preserved through time. Everything from complete arthropods to feathers, small reptiles, flowers. All perfectly preserved, to microscopic level, have been found inside these tiny golden time machines. The oldest known pieces of amber come from 320 million year old rocks, the last remains of an ancient Carboniferous swamp forest.

The three fossiliferous amber droplets from the Dolomite Mountains
Earlier this year, a team of palaeontologists, led by Eugenio Ragazzi and Guido Roghi from the University of Padova, recovered 70,000 of tiny amber droplets from the Dolomite Mountains in the Trentino-Alto region of Italy. The Dolomites are composed, almost entirely, of Triassic rocks.

The droplets are of the same age. What makes them special is the two tiny mites and single fly trapped inside the dark, plum coloured resin. Just 2 to 6 millimeters in length, the droplets only gave up their secrets under the microscope. All 70,000 were screened by a German team of scientists, led by Alexander Schmidt, of Georg-August University, Göttingen. Plant material was common, but only 3 gave up arthropods, 2 gall mites and fly.

Unfortunately, the only well preserved part of the fly were the antennae, meaning that the species could not be identified. The gall mites, however, were far more complete. Right off the mark, they were identified as unknown species and given the names of Triasacarus fedelei and Ampezzoa triassica. Further analysis revealed that the two arthropods were part of a class of gall mites known as the eryophyoids.

The two 230 million year old gall mites. Triascarus
is on the left and Ampezzoa triassica
An extremely specialized but successful group with over 3500 living species, all feed on leaves (in fact, both fossil mites were preserved on the surface of an extinct cheirolepidiacead conifer leaf which helped in their identification) and have unique adaptations to aid them in their daily lives. The fossils possessed all such features, showing that they were not transitional forms and were actually very close to their modern counterparts.

'You would think that by going back to the Triassic you'd find a transitional form of gall mite, but no,' said Dr David Grimaldi, author of the paper published on the amber creatures and a curator and world expert on fossil arthropods at the American Natural History Museum's Division of Invertebrate Zoology. '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.'

What makes these fossil mites even more special is what they show us about the group's evolutionary history as a whole. Today, almost all species of gall mite feed on flowering plants. However, these mites existed prior to the evolution of such plants. 'We now know that gall mites are very adaptable,' added Grimaldi. '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.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. It's an important time to study if you want to know how life evolved.' Amber fossils are perhaps the most valuable that we have. Not only is the level of preservation perfect, each one is a tiny piece of a lost ecosystem frozen in time.

As analysis techniques become more advanced we will be able to look further back in time and discover a wealth of detail and accuracy rivaled only by that of the mammoths and their genome. While it is a billion to one chance, it is possible that Jurassic Park could become a reality. What ever the case, the amber time machine will continue to spring new surprises.