MID DEVONIAN PHYLLOCARID CRUSTACEA FROM BOLIVIA

The Givetian Dipleura dekayi Zone of the Bolivian Altiplano, and adjac ent stratigraphical levels, yield representatives of the phyllocarid g enera Echinocaris and Dithyrocaris. The peculiar morphology and well-p reserved original features of the exoskeleton allow erection of a new species, Echinocaris spiniger sp. nov. Discovery of a carapace with ab dominal somites still connected allows identification of the correspon ding tail piece and description of the complete exoskeleton of Dithyro caris oculeus sp. nov., probably one of the earliest representatives o f the genus. Palaeobiological and taphonomic data regarding these spec ies are discussed. Two other forms, represented by only few specimens from other isolated localities, are provisionally left in open nomencl ature: Echinocaris sp. and Dithyrocaris sp.