NSF Award
0106309
INSECT AND VERTEBRATE FAUNAS OF A UNIQUE LATE TRIASSIC FRESHWATER ECOSYSTEM IN EASTERN NORTH AMERICA<br/><br/>Nicholas C. Fraser and David A. Grimaldi<br/>EAR-0106309<br/><br/>The end of the Triassic period (230 -200 mya) was a pivotal time in the evolution of modern terrestrial ecosystems. There is a good global record for tetrapods, including the first mammals, crocodiles, turtles, lissamphibians (frogs and salamanders), sphenodontians, and, by extension, their sister taxon, the lizards. By contrast the record for the most significant group of modern day animals, the insects, is considerably poorer. Only a handful of rich insect-producing Triassic sequences are known worldwide, and the majority of fossils from these localities comprise incomplete specimens such as isolated wings and elytra. <br/><br/>A single site in the Newark Supergroup of eastern North America has been found to contain numerous complete Late Triassic insects. The Solite Quarry is situated on the Virginia-North Carolina state line, and it has produced the oldest global records for water bugs, thrips and caddisflies. Other fossils found to date include a unique gliding reptile and numerous specimens of a small aquatic reptile that frequently preserve details of their soft part anatomy. These have yet to be fully described. Only a relatively small portion of the fossiliferous sequences has been excavated and PIs will open large-scale excavations in the most productive quarry units. The next phase of the work will be to conduct detailed studies of all the finds and to compare them with the two major assemblages that share the most in common: the Madygen Formation of Kirghizistan and the Molteno Formation of South Africa. The exquisite preservation of the Solite insects will permit a complete re-evaluation of the extensive Russian and South African insect collections and thereby allow for a better understanding of the mode and tempo of insect evolution and radiation at this critical time.<br/><br/>For a long time the Solite quarry was regarded as being largely unfossiliferous. Certainly the microscopic insect fossils can be readily overlooked under normal lighting conditions. The search image is critical to the PIs success, and using the same methods they have identified other localities nearby that also contain insect remains. Together with the diverse plant and vertebrate remains, they shall reconstruct a detailed picture of marginal freshwater ecosystems in the Late Triassic.
