Decapod Crustacea from the Agrio Formation (Lower Cretaceous) of the Neuquén Basin, Argentina

Two species of decapod crustacean are recordedfrom the Agua de la Mula Member of the Agrio Formation(Upper Hauterivian – Lower Barremian) of the Neuque´nBasin of west-central Argentina, namely Astacodes falcifer Belland a new species of Palaeohomarus, P. pacificus. The preser-vation of the specimens is exceptional, some showing delicatecompound eyes and a stridulatory apparatus, features rarelyfound in fossil forms. Many specimens are preserved articu-lated inside calcareous nodules, within dark-grey shales. Thelobster-bearing sediments accumulated in a low-energy mar-ine environment and diagenetic mineralization occurred veryrapidly, prior to significant decay, thus allowing exceptionalpreservation of specimens. Palaeohomarus was a rare genusin the Cretaceous with a palaeogeographic distributionrestricted to the Mediterranean Tethys, the eastern USA andMadagascar, while Astacodes falcifer has been recorded onlyfrom Speeton (eastern England) and Neuque´n. Key words: Crustacea, Lower Cretaceous, Argentina, excep-tional preservation, eyes, stridulatory structure.T