Explaining about Archaeopteryx
Earlier this week, Everything Dinosaur was emailed by a young dinosaur fan who asked about a prehistoric animal named Urvogel. She had come across it whilst learning about the famous fossil site of Solnhofen in southern Germany. The word “Urvogel” is German and it means “first bird”, it refers to Archaeopteryx (A. lithographica), the fossils of which are synonymous with the finely grained limestone beds of the Solnhofen quarries.
The Ancient “Dino-Bird” Archaeopteryx
Picture Credit: Carl Buell
Palaeontologists now know that this creature, fossils of which show a transitional form between Theropod dinosaurs and birds, was probably not the first bird to evolve. However, when a spectacular fossil discovery was announced in 1861, Archaeopteryx became the first feathered fossil of its kind to be formerly studied and its fossils caused a sensation, as only two years before Charles Darwin had published “The Origin of Species” that outlined the case for evolution and natural selection.
The Solnhofen limestone deposits are finely grained and they outcrop in an east to west belt north of Munich and south of Nuremberg. Hundreds of fossils of invertebrates have been found and the vertebrate fauna preserved includes over fifty types of fossil fish, around thirty reptiles (Pterosaurs, marine reptiles, dinosaurs and crocodiles). The Solnhofen deposits are regarded as a Lagerstätte. This is a German phrase from the words Lager (which means storage) and Stätte (which means place). It refers to a deposit of sedimentary strata that contains a lot of fossil material that is exceptionally well preserved.
During the Late Jurassic, shallow tropical lagoons and small islands stretched all the way from Portugal in the south through France and into southern Germany. Coral reefs formed in the tropical seas and these reefs split the coastline up forming a series of isolated lagoons. These lagoons were cut off from the sea and also from terrestrial run off. The salinity levels rose in the lagoons and the water may have become oxygen deficient. This made the mud on the bottom of these lagoons almost devoid of life so any animal or plant remains that drifted into the lagoon was not consumed by scavengers. The almost stagnant waters had little current so the remains of corpses were not broken up. Organisms buried by the soft, carbonate muds and formed as fossils in the finely grained sediment therefore have exceptional details preserved and many of these body fossils are almost complete.