The family Ulugkemiidae Novozhilov, 1958 (Conchostraca) in the Triassic ofArgentina: paleobiogeographic implications

The first record of the family Ulugkemiidae from the Triassic of Argentina is reported. The family was previously known only from Devonian and Late Pa leozoic beds of Russia. After a careful comparison with the known represent atives of the family and allied forms, the studied material is assigned to a new genus Triasulugkemia and to two new species T. ischichucaensis and T. shenyanbini. The specimens were collected in two fluvio-lacustrine rift ba sins from western Argentina: Ischigulasto-Villa Union and Cuyo. The occurre nce of a Paleozoic Asian conchostracan family in the Triassic of southweste rn Gondwana contributes to the discussion of current hypothesis for the flo ral and faunal interchange between Asia and Gondwana during Late Paleozoic and Early Mesozoic times.