Ordovician phyllocarids (Arthropoda; Crustacea) from Argentina

New phyllocarids are described from the Ordovician (early Arenig to lower Caradoc) of the Precordillera and Eastern Cordillera of Argentina, namelyCaryocaris delicatus n. sp.,Caryocaris sp. 1, ?Caryocaris sp. 2,Pumilocaris granulosus n. gen., n. sp., ?Pumilocaris sp. and an undetermined form. They all occur in graptolite-bearing shales. A critical review of the South American phyllocarids formerly described in the literature is made andCaryocaris delicatus n. sp. (Llanvirn) is compared with congeneric species known from the Ordovician (Tremadoc-Caradoc) of North America, Europe, China and Australia. The presence ofCaryocaris in South America is therefore attested, which confirms the view that the genus had a worldwide distribution in the lower Ordovician in relation with a possible pelagic lifestyle. A new definition ofCaryocaris is proposed and the former subdivision of the genus C. (Caryocaris) andC. (Rhinopterocarys)] abandoned. A set of original characters (e.g. lack of rostral plate, short leaflike furcal rami, short telson, extremely thin carapace) strongly indicates thatCaryocaris lies outside the Ceratiocarididae and may form the basis of a new taxonomic unit.