Pseudastacus

Article summary

Pseudastacus (meaning 'false Astacus , in comparison to the extant crayfish genus) is an extinct genus of decapod crustaceans that lived during the Jurassic period in Europe, and possibly the Cretaceous period in Lebanon. Many species have been assigned to it, though the placement of some species remains uncertain and others have been reassigned to different genera. Fossils attributable to this genus were first described by Georg zu Münster in 1839 under the name Bolina pustulosa, but the generic name was changed in 1861 after Albert Oppel noted that it was preoccupied. The genus has been placed into different families by numerous authors, historically being assigned to Nephropidae or Protastacidae. Currently, it is believed to be a member of Stenochiridae. Reaching up to in total length, Pseudastacus individuals were small animals. Members of this genus have a crayfish-like build, possessing long antennae, a triangular rostrum and a frontmost pair of appendages enlarged into long and narrow pincers. Deep grooves are present on the carapace, which is around the same length as the abdomen. The surface of the carapace is usually uneven, with either small tubercles or pits. Sexual dimorphism is known in P. pustulosus, with the pincers of females being more elongated than those of the males. There is evidence of possible gregarious behavior in P.…

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