4.3" Horseshoe Crab (Mesolimulus) Fossil - Solnhofen Limestone

This is a rare and high quality, fossil horseshoe crab (Mesolimulus walchi) from the famous Solnhofen Lagerstätte in Germany. It's 4.3" in length and preserved ventrally on an unbroken, rectangularly cut slab of limestone.

Mesolimulus is an extinct genus of arthropod. The best known examples are found in Solnhofen limestone near Solnhofen, Bavaria, Germany. Originally assigned to the living genus Limulus, they are related to and look virtually identical to the modern horseshoe crab. Other species assigned to Mesolimulus have been recorded from Spain, Siberia and (questionably) from Lebanon. Horseshoe crabs in general date to the Ordovician Period, more than 440 million years ago, and late Paleozoic Euproops fossils indicate that they have changed little over the last 300 million years.

The Solnhofen limestones is a famous Lagerstätte in Germany that offer amazing preservation of Upper Jurassic fossils. It is where on of the most famous fossils of all time, Archaeopteryx was found. The fine grained limestone makes excellent building materials which has let to heavy quarrying over the past two centuries which as a result has led to some amazing fossils being unearthed.

This area represented an archipelago at the edge of a sea. Due to high salt content, the lowest levels in the water column could not support much life and was devoid of oxygen. This lack of scavengers on the bottom of the sea led to amazing preservation of the fauna found there.