A new crayfish Family (Decapoda : Astacida) from the Upper Jurassic of China, with a reinterpretation of other Chinese crayfish taxa

抄録

The highly sporadic fossil record of freshwater crayfish is improved by the discovery of several new specimens from the Upper Jurassic Jehol Group of Liaoning Province, north-east China. As a result of work on this material, the Family Cricoidoscelosidae is erected to accommodate specimens possessing highly atypical features among the Infraorder Astacidea belonging to the new genus and species Cricoidoscelosus aethus. Furthermore, Astacus spinirostrius Imaizumi (1938) is synonymized with A. lincenti van Straelen (1928b) and is moved from the Family Astacidae to the family Cambaridae and to the new genus Palaeocambarus. Thus, a solution is suggested to the problematic biogeographic issue of the presence of the genus Astacus in a region presently occupied only by cambarid crayfish, a generic assignment that was made tentatively in the first place. In addition, new questions now arise with respect to the origins and early development of crayfish in the Asiatic region and perhaps even globally.