UNESCO World Heritage Messel Pit Fossil Site

The world-famous fossil site “Messel Pit” became a UNESCO World Heritage Site in 1995. In the past, the pit was used industrially for the extraction of crude oil (mineral oil). After the industrial use was discontinued, scientists conducted numerous digs in the area that unearthed a large number of impressive treasures. Many of the exquisitely preserved fossils of animals and plants also allow conclusions about the ecosystem in Messel 48 million years ago.

The tropical climate conditions favored the rapid development of a vegetation cover: shrubs, vines, trees and ferns surrounded the lake and stabilized the crater’s rim with their roots. Algae and a carpet of aquatic plants gave the water a dark green to brownish color, and animals began to populate the newly formed habitat as well. In this process, the upper layers of the lake were clearly favored, since they alone offered sufficient heat and particularly oxygen for the majority of living organisms. The calm and dark bottom was untouched by currents and only housed highly specialized bacteria that do not require oxygen for their survival and feed of the sunken remains of dead animals. The high number of fossilized birds and bats, which hunted close to or above the water and later were submerged in the lake, suggests that toxic gases may have risen from the water’s surface.

Since the bottom of the Messel Lake was free of oxygen or currents that could move or fragment the sunken animals and plants, fossils were particularly well preserved in this environment. This is due to the fact that dead organisms can only be preserved over time if they are rapidly and completely covered by sediments. In the course of many millennia, the deposits of clay and single-celled green algae led to the formation of so-called oil shale at the lake bottom. The innumerable instructive fossil discoveries from Messel were all contained in this layer. Thus, a piece of oil shale with a thickness of a mere ten centimeters can reveal a thousand years of geological history.

About half of the specimens recovered at Messel are plants. The examination of their exterior appearance allows conclusions as to the climatic and environmental conditions at the time when these plants grew. For example, the size and shape of the leaves can reveal information about the mean annual temperature or the amount of precipitation. And even the percentage of carbon dioxide in the air can be determined by studying the stomata on the underside of the leaves under a microscope. 

Although no more than eight species of fishes have been discovered in the Messel Lake, they account for 90 % of all vertebrates found at the site. In particular, catfish and the species of gar pictured here with its exceptionally well preserved scale armor are among the more frequent discoveries. In its outward appearance, the latter barely differs from its modern-day relatives.

The terrestrial insect eaters often used different strategies to access their food. While some of them ate fruit and scraped the ground in search of insects, the hedgehog relative Macrocranion tupaiodon was an omnivore with a predilection for fish. It frequently approached the lake shore to search for dead fishes. This is suggested by its unspecialized teeth as well as preserved stomach contents. The animal, which reached a length of 30 centimeters, had elongated ears and equally long tactile hairs on its snout, which indicate a well-developed sense of touch, smell and hearing. In addition, the short forelegs and relatively long hind legs reveal it as an agile and swift denizen of the forest floor.

Prosimians turned to the foliage cover of dense forests to seek protection from predators and occasional flooding. Europolemur kelleri, which was about as big as a domestic cat, used all four of its extremities to climb and jump among the trees. Other species of prosimians found at Messel only reached half that size. Contrary to the prehistoric horses, nothing is known about the prosimians’ reproductive biology; however, it can be assumed that they produced one to two offspring a year, similar to the modern-day lemurs.

This snake with a length of one meter stands out even among the most exquisitely preserved objects from the Messel Pit. It is the young of an extinct species of boa, and even some of its scales have been preserved. Shortly before its death, it devoured a lizard of the basilisk tribe (Geiseltaliellus maarius), which, in turn, had recently eaten an insect. All three are visible – can you find them?

The ornate-headed lizard owes its name to its outward appearance. It has an extremely slender body with a particularly long prehensile tail and a massive, ornate head. In conjunction with its curved claws, these characteristics hint at an arboreal lifestyle. However, the lizard does not appear to have been a swift hunter but rather a large plant eater, which presumably also fed on insects from time to time. To date, only six specimens have been found.

This specimen has become downright famous. Like one of the prehistoric horses, it already served as the subject of a postage stamp, and in 1993, it was even taken into space as a mascot aboard the space shuttle Columbia. It is Palaeochiropteryx tupaiodon, by far the most common species of bat from the Messel Pit. The smallest among the bats found at Messel, it reached a wingspan of 25 to 30 centimeters.