NEW PERSPECTIVES ON LATE TRIASSIC INSECT DIVERSITY
AS REVEALED BY A LOCALITY IN THE DANVILLE BASIN
FRASER, N.C., Virginia Museum of Natural History,
Martinsville, VA 24112
GRIMALDI, D.A., American Museum of Natural History,
Central Park West at 79th Street, New York, NY
10024-5192
In general terms, Triassic sediments are often regarded as being rather
unfossiliferous. This is particularly true for terrestrial invertebrates,
and it is highlighted by the fact that, worldwide, there are numerous
Permian and Jurassic sites containing diverse insect faunas. By
contrast, there are no similar Triassic localities producing rich
assembalges of insects. This rather poor fossil record has been
literally taken by some authorities as evidence that the Triassic
represents a "bottle-neck in diversity" resulting from the great end-
Permian extinction.
A Carnian locality on the North Carolina-Virginia border is
yielding an incredibly diverse flora and fauna, and includes the oldest
definitive records for a number of modern families of insects. For
example, the presence of at least six families of dipteran indicate that
this important order originated at least by the Middle Triassic.
Furthermore, the assemblage also includes taxa previously only
recorded in the southern hemisphere.
The new finds suggest that putative low diversities in Triassic
insect assemblages may after all be merely a product of a lack of
collecting effort and/or inappropriate sampling methods. Sharp
distinctions between the Triassic of Laurasia and Gondwana also need
to be reassessed.
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