Intense drilling in the Carboniferous brachiopod Cardiarina cordata Cooper, 1956 |
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Authors: | ALAN P HOFFMEISTER MICHA KOWALEWSKI RICHARD K BAMBACH TOMASZ K BAUMILLER |
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Institution: | Department of Geological Sciences Indiana University 1001 E. Tenth Street Bloomington IN 47405 USA, A. P. Hoffmeister [];Department of Geological Sciences Virginia Polytechnic Institute and State University Blacksburg VA 24061 USA;Botanical Museum Harvard University 26 Oxford Street Cambridge MA 02138 USA;Museum of Paleontology University of Michigan Ann Arbor MI 48109 USA |
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Abstract: | The brachiopod Cardiarina cordata, collected from a Late Pennsylvanian (Virgilian) limestone unit in Grapevine Canyon (Sacramento Mts., New Mexico), reveals frequent drillings: 32.7% (n = 400) of these small, invariably articulated specimens (<2 mm size) display small (<0.2 mm), round often beveled holes that are typically single and penetrate one valve of an articulated shell. The observed drilling frequency is comparable with frequencies observed in the Late Mesozoic and Cenozoic. The drilling organism displayed high valve and site selectivity, although the exact nature of the biotic interaction recorded by drill holes (parasitism vs. predation) cannot be established. In addition, prey/host size may have been an important factor in the selection of prey/host taxa by the predator/parasite. These results suggest that drilling interactions occasionally occurred at high (Cenozoic-like) frequencies in the Paleozoic. However, such anomalously high frequencies may have been restricted to small prey/host with small drill holes. Small drillings in C. cordata, and other Paleozoic brachiopods, may record a different guild of predators/parasites than the larger, but less common, drill holes previously documented for Paleozoic brachiopods, echinoderms, and mollusks. |
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Keywords: | Brachiopod Carboniferous Drilling Parasitism Predation |
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