NEW PYGOCEPHALOMORPH CRUSTACEANS FROM THE PERMIAN OF CHINA AND THEIR PHYLOGENETIC-RELATIONSHIPS

Members of the malacostracan order Pygocephalomorpha are among the mos t characteristic elements in nearshore marine and freshwater communiti es in the Carboniferous and Permian of Europe and North America. A new family of pygocephalomorph Eumalacostraca, Tylocarididae, with two ne w monospecific genera, is described from China, where it occurs in the Early Permian Tungtzeyen Formation of Fujian, and in the Late Permian Lungtan Formation of Hunan. The descriptions of Fujianocaris bifurcat us gen. et sp. nov. and Tylocaris asiaticus gen. et sp. nov. are based on dorsally preserved isolated carapaces, some showing incomplete abd ominal details, but with no complete tail fans. Opinions on the affini ties of Pygocephalomorpha to other malacostracans have varied but they are generally regarded as a separate order of 'mysidacean' peracarids . Hitherto the phylogeny of the group has not been considered, and the current family level taxonomy remains rather artificial. A cladistic analysis of fossil and Recent 'mysidacean' and pygocephalomorph crusta ceans is presented here which outlines the affinities within the group and holds promise for an eventual natural taxonomy of the Pygocephalo morpha.