Review of the Early and Middle Jurassic erymid lobsters (Crustacea: Decapoda)

Abstract

Erymid lobsters (Crustacea, Decapoda, Erymidae) are an important component of Mesozoic crustacean faunas in Europe, especially during the Jurassic. The 29 species reported from the Early and Middle Jurassic are the oldest found in Western Europe and North America, and constitute an important part of the evolutionary history of these lobsters. After the review presented here, 24 species are maintained within the genera Eryma Meyer, 1840 (7 species), Palaeastacus Bell, 1850 (5 species), Pustulina Quenstedt, 1858 (2 species) and Stenodactylina Beurlen, 1928 (9 species). All these species, with the exception of Eryma ventrosum (Meyer, 1835), have a new description and the diagnoses of the genera Eryma, Palaeastacus and Stenodactylina are emended. Four species are transferred to another genus: Palaeastacus numismalis (Oppel, 1862) n. comb., Palaeastacus foersteri (Feldmann, 1979) n. comb. and Stenodactylina guisei (Wright, 1881) were previously assigned to Eryma, and Stenodactylina spinosa (Étallon, 1861) n. comb. was previously assigned to Palaeastacus. Our study shows that Stenodactylina was the most diversified genus in Early – Middle Jurassic, but the fossils of Eryma are more common. Furthermore, Eryma compressum (Eudes-Deslongchamps, 1842) is the emblematic species of Erymidae Van Straelen, 1925 during the end of Early Jurassic and Middle Jurassic in Western Europe (Toarcian – Bathonian). This species includes now Eryma bedeltum (Quenstedt, 1858) in its synonymy. The genus Pustulina is very rare and the specimens show some characteristics on their carapace recalling other erymid genera (an almost sinuous hepatic groove for example), that are absent in more recent species. Finally, we point out that only E. compressum, P. foersteri and Stenodactylina walkerae (Feldmann and Haggart, 2008) are reported outside Europe.