Wu, Wenying , Labandeira, Conrad C. , Hotton, Carol L. , Stein Jr, William .
Bored fungi: Prototaxites-arthropod interactions during the Devonian.
Prototaxites was a massive, columnar thallus up to 8 m in height and 1 m in diameter, occurring from mid Late Silurian to latest Devonian terrestrial and nearshore marine deposits in many areas of the world. Two specimens of bored Prototaxites, one from the Early Devonian (Emsian) of GaspĂ©, Quebec, and other from the Late Devonian (Famennian) of Kettle Point, Ontario, provide very early examples of terrestrial arthropod-fungal interactions. Borings consistent with an arthropod origin exhibit several characteristics, including a stereotyped tunnel geometry, distinctive internal frass, and coprolite size ranges consistent with arthropod growth-stage increments. The Kettle Point specimen demonstrates the earliest probable example of terrestrial fungivory. The network of borings in the Kettle Point specimen exhibits several features involving arthropod penetration of live fungal tissue, perhaps analogous to extant beetle borings in hardened bracket fungi. An inner, thin but variably thickened, opaque region of hyphal mat lines the tunnels and suggests host response to wounding. Coprolites, 0.1-2.0 mm in diameter, bear degraded tubular (hyphal) structures that occasionally protrude above their smooth surfaces, suggestive of digestive processing. Three dimensional reconstruction of the tunneling network reveals centrally located, unoriented channels interrupted occasionally by more expansive galleries. Although the arthropod culprit remains unidentified, Devonian possibilities include oribatid mites. However, the disparity between small coprolite size and a much larger tunnel diameter is incongruous. These networks also are inconsistent with known myriapod life-habits, and additionally any similarity to holometabolous larval or adult insect borings is countered by a 55 million year gap before the earliest occurrences of such derived insects. Preliminary study of the Early Devonian GaspĂ© specimen shows only peripheral borings and a different pattern of tunnel geometry, suggesting a different arthropod feeder.
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1 - Smithsonian Institution, National Museum of Natural History, Department of Paleobiology, MRC 121, P.O. Box 37012, Washington, DC, 20013, USA
2 - State University of New York at Binghamton, Department of Biological Sciences, Vestal Parkway East, P.O. Box 6000, Binghamton, NY, 13902, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 3:15 PM