Horsehoe Crab Death Track

Late Late Jurassic, Tithonian Age. Solnhofen Lithographic Limestone. Solnhofen, Bavaria, Germany. The tracks record the last few feet of life for a horseshoe crab (Mesolimulus walchi.) This hapless creature – whose species has remained virtually unchanged over the last 450 million years – ended up trapped in a toxic lagoon, where the combination of a hot, tropical climate and limited water exchange with the ocean created an oxygen-poor environment. Evaporation also concentrated salts in the water and created a hyper-saline layer near the lagoon. The conditions proved fatal to the horseshoe crap, but preserved its body from scavengers and decay.