532 J. Paleont., 74(3), 2000, pp. 532–543 Copyright  2000, The Paleontological Society 0022-3360/00/0074-0532$03.00 DRILL HOLES IN SHELLS OF PERMIAN BENTHIC INVERTEBRATES MICHAL KOWALEWSKI, 1 MARCELLO G. SIMO ˜ ES, 2 FERNANDA F. TORELLO, 2,3 L. H. C. MELLO, 2, 3 AND RENATO P. GHILARDI 2,3 1 Department of Geological Sciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall, Blacksburg, Virginia 24061, michalk@vt.edu, 2 Instituto de Biocie ˆncias, Universidade Estadual Paulista, Campus de Botucatu, Rubia ˜o Ju ´nior, Botucatu, SP, CEP 18.618-000, 3 Instituto de Geocie ˆncias, Universidade de Sa ˜o Paulo, Sa ˜o Paulo, SP, CEP 05422-970 ABSTRACT—Newly discovered benthic fossils and specimens illustrated in the paleontological literature indicate that drilling predators (or parasites) were present in the Permian. New field data from southern Brazil document the first drill holes ever reported for Permian bivalve mollusks. In addition, a literature review revealed drill holes in shells of articulate brachiopods from Russia, Greece, and West Texas. Holes range in size from 0.1 to 5.8 mm and are typically round, cylindrical, singular penetrations perpendicular to the valve surface. Incomplete, healed, and multiple holes are absent. Drilling frequency, a proxy for predation intensity, is very low: less than 1 percent (this estimate may be seriously affected by taphonomic and monographic biases). Literature data suggest that frequency of drilled specimens varied significantly among higher brachiopod taxa. The geography and stratigraphy of drilled specimens indicate that drilling organisms were worldwide in their occurrence and continuously present in marine ecosystems throughout the Permian. This report is consistent with other recent studies indicating that although drillers were continuously present throughout the Phanerozoic, drilling intensity was lower in the Late Paleozoic and early Mesozoic. INTRODUCTION D RILL HOLES OF predatory origin are ubiquitous in the Cre- taceous and Cenozoic marine fossil record and have been studied intensely by paleontologists (e.g., Taylor, 1970; Hoffman et al., 1974; Thomas, 1976; Vermeij et al., 1980; Kitchell et al., 1981; Vermeij and Dudley, 1982; Hoffman and Martinell, 1984; Colbath, 1985; Kowalewski 1990; Allmon et al., 1990; Ander- son et al., 1991; Kelley and Hansen, 1993, 1996; Hansen and Kelley, 1995). In contrast, the pre-Cretaceous record of drilling predation has long been considered scarce, discontinuous, and questionable. Indeed, many holes reported in the earlier literature (e.g., Fenton and Fenton, 1931; Bucher, 1938) may have been nonpredatory in origin (see Carriker and Yochelson, 1968; Rich- ards and Shabica, 1969). However, numerous recent studies in- dicate that the Paleozoic-Mesozoic record of drilling predation is much more continuous and substantially richer than previous- ly thought. Although relatively scarce compared to the Ceno- zoic, borings of predatory (or parasitic) origin are present in marine fossils of the late Precambrian (Bengtson and Zhao, 1992), Cambrian (e.g., Miller and Sundberg, 1984; Conway Morris and Bengtson, 1994), Ordovician (e.g., Cameron, 1967; Rohr, 1990), and Silurian (e.g., Rohr, 1976; Liljedahl, 1985; Chatterton and Whitehead, 1987). Moreover, drilling predators apparently became relatively more common and widespread in the Devonian and Carboniferous (Brunton, 1966; Buehler, 1969; Sheehan and Lespe ´rance, 1978; Ausich and Gurrola, 1979; Smith et al., 1985; Brett and Bordeaux, 1990; Baumiller, 1990, 1993, 1996; Baumiller and Macurda, 1995; Leighton, 1998; Baumiller et al., 1999), possibly reflecting the mid-Paleozoic marine revolution (Signor and Brett, 1984; Smith et al., 1985; Kowalewski et al., 1998; Kowalewski and Bambach, 1998; Bambach, 1999). Also, in the early to mid Mesozoic, drilling predation, although scarce and only locally important, appears to have been continuously present, during both the Triassic (Newton, 1983; Fu ¨rsich and Jablonski, 1984) and the Jurassic (Harper et al., 1998; Kowalewski et al., 1998). The Permian is the only geologic period that lacks good doc- umentation. An extensive survey of the literature on drilling pre- dation turned up only three works that included information on Permian drill holes: Yakovlev (1926), Hecker (1965), and Grant (1988). Grant (1988) illustrated five drilled specimens of the brachiopod Disphenia myiodes from the Upper Permian Epis- kopi Limestone (Greece) and reported that many specimens had circular borings ranging in diameter from 0.1 to 0.3 mm. Six brachiopods with holes of possibly predatory origin were illus- trated from the Permian of Russia: five by Yakovlev (1926, tbl. IX) and one by Hecker (1965, pl. 3, fig. 1). However, the more specialized, monographic taxonomic literature has not yet been mined for illustrations of drilled specimens of Permian age. Here, we combine new data on drilled bivalves from the Up- per Permian deposits of the Parana ´ Basin (Brazil) with the data provided by Yakovlev (1926), Hecker (1965), and Grant (1988). In addition, to evaluate taxonomic monographs as a potential source of information on drill holes, we have surveyed the ex- tensive monograph on Permian brachiopods of west Texas (Coo- per and Grant, 1972, 1974, 1975a, 1975b, 1976a, 1976b, 1976c) as well as numerous monographs and papers on Permian bi- valves of Australia, New Zealand, Africa, and South America (see below for references). MATERIAL AND METHODS All drilled specimens of bivalve mollusks analyzed here were field-collected as part of a large project on the paleobiology, taphonomy, and paleoecology of bivalve-dominated assemblag- es of the Upper Permian deposits of Parana ´ Basin, Brazil (see Torello and Simo ˜es, 1994; Simo ˜es et al., 1996, 1998; Simo ˜es and Kowalewski, 1998 and references therein). The drilled spec- imens were collected from three localities of siliciclastic deposits of the Corumbataı ´ and Terezina Formations. These Late Permian formations may be either Kazanian or Tatarian in age (see Dae- mon and Quadros, 1970; Daemon, 1974; Valencio et al., 1975; Rohn, 1994; Simo ˜es and Kowalewski, 1998). The analyzed specimens all are silicified body fossils extracted from large sandstone blocks or collected directly from outcrop walls (see Simo ˜es and Fittipaldi, 1992; Simo ˜es et al., 1996; Simo ˜es and Kowalewski, 1998 and references therein for procedural details). A total of 2,810 specimens of bivalves have been collected over the last several years and all specimens with holes of possibly predatory origin were set aside during the initial screening of samples. The drilled specimens were analyzed and measured under a binocular microscope with the measurement accuracy of  0.1 mm. The specimens are housed in the Paleontological Collection of the Department of Zoology, Institute of Biosci- ences, Sao Paulo State University, Botucatu, Brazil (prefixed DZP-A1-G).