'Pompeii' salamanders fill fossil gap

The quality of preservation has thrilled researchers

A collection of petrified Chinese salamanders is giving scientists valuable new information about amphibian evolution.

The little animals were suffocated en masse 150 million years ago when their pond, near Fengshan in Hebei Province about 400 kilometres (250 miles) north of Beijing, was smothered in volcanic ash.

A juvenile salamander: The arrows point to impressions left by external gills

It was, say researchers, a salamander equivalent of the eruption of Vesuvius in AD 79, which had a similar petrifying effect on the residents of nearby Pompeii.

The detail in the specimens is astonishing. The preservation process was so good that in some instances even the soft internal organs have left their mark.

The salamanders, which were recovered from an area no bigger than 10 metres square, are described in the journal Nature by Neil Shubin, of the University of Chicago, and Ke-Qin Gao, of the American Museum of Natural History in New York, US.

The specimens, which record both laval and adult stages, are 85 million years older than any other salamanders pulled out of the fossil record. They hint at an Asian origin for the creatures and show clearly that the animals have changed very little since they were running under the feet of dinosaurs in the Jurassic Period.

"Whether you look at a salamander you find under a rock in the local forest preserve or in a rock in China dating back 150 million years, they look alike," Shubin said.

"In fact, they look alike in great detail - the bones in their wrists are the same, the way their skulls are formed - intricate details are the same."