Conchostracans or clam shrimp (order Conchostraca Sars) are arthropods with a carapace consisting of two chitinous lateral valves. Triassic conchostracans range in size from 2 to 12.5 mm long and are common in deposits that formed in fresh water lakes, isolated ponds and brackish areas. Their dessication-and freeze-resistant eggs can be dispersed by wind over long distances. Therefore many conchostracan species are distributed throughout the entire north-ern hemisphere. In the Late Permian to Middle Triassic interval, several of these forms are also found in Gondwana. Many wide-ranging conchostracan species have short stratigraphic ranges, making them excellent guide forms for subdivision of Triassic time and for long-range correlations. The stratigraphic resolution that can be achieved with conchostracan zones is often as high as for ammonoid and conodont zones found in pelagic marine deposits. This makes con-chostracans the most useful group available for biostratigraphic subdivision and correlation in continental lake deposits. Upper Triassic Gondwanan conchostracan faunas are different from conchostracan faunas of the northern hemisphere. In the Norian, some slight provincialism can be observed even within the northern hemisphere. For example, the Sevatian Redondestheria seems to be restricted to North America and Acadiestheriella n. gen. so far has been found only in the Sevatian deposits from the Fundy Basin of southeastern Canada. Here we establish a con-chostracan zonation for the Changhsingian (Late Permian) to Hettangian (Early Jurassic) of the northern hemisphere that, for the most part, is very well correlated with the marine scale. This zona-tion is especially robust for the Changhsingian to early Anisian, late Ladinian to Cordevolian and Rhaetian to Hettangian intervals. For most of the Middle and Upper Triassic, this zonation is still preliminary. Five new genera, six new species and a new subspecies of conchostracans are described that are stratigraphically important. Half of the eight stage boundaries of the Triassic have been defined by a bio-event within a marine Global Stratotype and Point (GSSP) locality, and these definitions have been accepted by both the International Subcommission on Triassic Stratigra-phy and the International Commission on Stratigra-phy. The remaining four stage boundaries are nearing final definition. In the Lower Triassic, both the base of the Induan (priority: Brahmanian) Stage (¼ base of Triassic) and the base of the next younger Olenekian Stage have been firmly defined. In the Middle Triassic, there is wide agree-ment that the defining species for the base of the Anisian Stage should be Chiosella timorensis in the GSSP candidate site at Desli Caira (Romania), but there has not yet been a formal vote on this. The base of the overlying Ladinian Stage, however, has been firmly defined. In the Upper Triassic, the base of the Carnian has been firmly likewise defined, but there is not yet a final defi-nition for the boundaries of the overlying Norian and Rhaetian stages. A consensus has not been reached on a defining species for the base of the Norian or its GSSP locality, but all of the different proposals under consideration do at least fall within a rather narrow stratigraphic interval. For the base of the Rhaetian, Misikella posthernsteini Kozur & Mock has been chosen as the defining species by the International Working Group on the Rhaetian stage, and the GSSP candidate locality at Steinbergkogel (Austria) has been studied in detail by a group under the leadership of L. Krystyn (Vienna) and presented to the participants of the International Conference on 'Upper Triassic Sub-divisions, Zonations and Events' in Bad Goisern in the autumn of 2008. The base of the overlying Hettangian stage (¼ base of the Jurassic) has been defined (so far only by a working group) as the FAD (First Appearance Datum) of Psiloceras spelae Guex, Taylor, Rakus & Bucher. The final definition of the Triassic stages within marine GSSP sections will be completed in the near future, but more than 50% of known Triassic rocks are of continental origin. Therefore, the main task of Triassic stratigraphers in the future will be subdivid-ing and correlating terrestrial strata, both between