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View - Kowalewski, M. - Virginia Tech

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BRETT AND WALKER—PREDATION IN PALEOZOIC MARINE ENVIRONMENTSFIGURE 6—Middle Paleozoic predatory fishes. 1—Rhenanid, ray-like placoderm Gemuendina, EarlyDevonian. 2—Ptyctodont placoderm Ctenurella, Devonian. 3—Upper and lower dentition of holocephalanDeltoptychius, showing hypermineralized tritor grinding gnathal plate. 4—Holocephalan Helodus,Pennsylvanian. 5—Stethacanthus; note toothed brush structure, Mississippian. 6—Eugeneodontiformeshark Sarcoprion; tooth whorl in lower jaw opposes pavement in rostrum, Pennsylvanian. 7—Hybodus,hybodont shark. 1, from Moy Thomas and Miles, 1971; 2, 3, from Stensiö, 1969; 4, from Patterson, 1965;5, 6, from Moy-Thomas and Miles, 1971; 7, from Zangerl, 1981.hard-shelled prey. These reef-dwelling fishes showmany similarities to specialized reefal teleost fishesof the Cenozoic (Moy-Thomas and Miles, 1971;Benton, 1997).There is limited information concerning thecoprolites or gut contents of the shark group.However, the few trace fossils available reveal thatbenthic organisms formed a food source for someof these predatory sharks. For example, coprolitesand gut contents of Carboniferous-Permianholocephalans, sharks, and other fish containfragmented brachiopods and crinoid ossicles(Zangerl and Richardson, 1963; Malzahn, 1968;Moy-Thomas and Miles, 1971).103

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