KELLOGG, DEREK W.* and EDITH L. TAYLOR. Department of Ecology and Evolutionary Biology and Museum of Natural History and Biodiversity Research Center, University of Kansas, Lawrence, KS 66047-7534 USA. - Evidence of wood-boring mites from the Paleozoic and Mesozoic of Antarctica.
Mites are important detritivores in the modern terrestrial ecosystem
and mite body fossils have been described as early as the Devonian.
Evidence of wood-boring mites is known from the Early Carboniferous to
the Quaternary in the form of tunnels preserved in permineralized or
petrified wood. In many cases, these tunnels contain coprolites whose
size and shape identifies them as being produced by mites (Acari).
Although mites were widespread wood borers during the Carboniferous,
by the Late Triassic insects appear to have taken over as the dominant
wood borers. Insect wood borers are believed to have evolved in the
Early Permian and they continue as the dominant agent in this syndrome
in modern ecosystems. From the Early Permian to the Late Triassic,
however, there are no reports of wood-borers, while in the Jurassic
and Cretaceous, there are very few records. We describe here evidence
of mite wood boring that fills this important evolutionary
"gap." Late Permian, Middle Triassic and Middle Jurassic
permineralized peats from the central Transantarctic Mountains,
Antarctica have yielded wood containing tunnels and coprolites
preserved within them. The coprolites fall into 5 size classes: 1 in
the Permian, 2 in the Triassic and 2 in the Jurassic. With the
possible exception of the largest coprolites from the Jurassic peat,
all are within the size range produced by modern and fossil mites. All
coprolites are circular to ovoid in shape and vary in their texture
from slightly compact with abundant recognizable tracheids (Permian)
to densely compact with no recognizable elements (2 Jurassic size
classes and 1 Triassic class). The significance of this material to
our understanding of wood-boring through time is discussed with regard
to the presumed change from mite-dominated detritivory in the
Paleozoic to an insect-dominated syndrome in the Mesozoic and
Cenozoic.
Key words: Antarctica, Jurassic, Permian, plant/animal interactions, Triassic, wood-boring mites