PRELIMINARY PATTERNS OF HERBIVORY ACROSS THE PERMIAN-TRIASSIC BOUNDARY IN THE DOLOMITES REGION, SOUTHERN ALPS, ITALY

The early Late Permian to early Late Triassic floras of the Dolomites Region in the Southern Alps of northeastern Italy has become more extensively documented in recent publications. These floras represent four major time intervals: (1), the early Late Permian (Wuchiapingian) of the Gröden Sandstone from the Bletterbach Gorge; (2), the early Middle Triassic (Anisian) of the Dont Formation from the Kühwiesenkopf locality; (3), the late Middle Triassic (Ladinian) of the Fernazza and La Valle Formations from Ritberg, Seewald and Innerkohlbach; and (4), the early Late Triassic (Carnian) of the Rio del Lago Formation from Dogna. These localities each provide from two to four plant assemblages that represent distinctive habitats as well as a continuous record of lycophytes, sphenophytes, pteridophytes, cycadophytes, coniferophytes, ginkgophytes and pteridosperms. Given the 40 million-year time span that straddles the PT-boundary, the abundance of documented plant assemblages and habitats, and a rich vascular plant record from latest Paleozoic to the early Mesozoic, the Dolomites Region is ideal for examining the role that the end-Permian event had on plant-insect interactions and for the response that a major environmental perturbation had on community structure. The paleoecological and temporal setting of the Italian Dolomites in Laurasia has parallels with the South African Karoo Basin in Gondwana. Although our examination of plant-insect associational patterns are preliminary, several patterns have emerged that contrasts Laurasia (Italy) with Gondwana (South Africa) during this crucial interval. First, herbivory levels are much lower in Laurasia throughout the entire section. Second, oviposition is the dominant Late Permian association in South Africa, but virtually absent in Italy. Third, there is an increase in plant-insect interactional diversity during the Middle to Late Triassic in both regions. Further future studies will considerably refine these patterns.