Pseudastacus is an extinct genus of decapod crustaceans that lived during the Jurassic period in Europe, and possibly the Cretaceous period in Lebanon. Reaching up to 6 cm (2.4 in) in total length, Pseudastacus had a crayfish-like build, with long antennae, a triangular rostrum and a frontmost pair of appendages enlarged into pincers, with those of females being more elongated. There is evidence of possible gregarious behavior in P. lemovices in the form of multiple individuals preserved alongside each other, possibly killed in a mass mortality event. With the oldest known record dating to the Sinemurian age of the Early Jurassic, and possible species surviving into the Cenomanian stage of the Late Cretaceous, Pseudastacus has a long temporal range and was a widespread taxon. Fossils of this animal were first found in the Solnhofen Limestone of Germany, but have also been recorded from France, England and Lebanon. All species in this genus lived in marine habitats. (Full article...)
