Records of the Western Australian Museum 17: 331-341 (1995). Acanthodian dental elements from the Trundle beds (Lower Devonian) of New South Wales CJ. Burrow Department of Zoology, University of Queensland, Queensland 4072 Abstract Acanthodian dental elements from the Trundle beds (Lochkovian- Pragian) of central New South Wales include dentigerous jaw bone fragments, tooth whorls, single teeth, and dentition cones sensu Valiukeviaus. Among acanthodians, only members of the Order Ischnacanthida possess an equivalent range of dental elements. Comparisons suggest that most of the Trundle beds elements belong to an ischnacanthid taxon with close affinity to Poracanthodes. Some other elements, distinctive tooth whorls including a type not previously described, possibly belong to a species with dentition that matches no known c1imatiid or ischnacanthid. INTRODUCTION The Class Acanthodii, as defined by recent workers (e.g., Denison 1979; Long 1986), has two orders which possessed teeth - the Climatiida and the Ischnacanthida. Amongst the climatiids, only fish of the family Climatiidae had teeth, comprising rows of tooth whorls. The Ischnacanthida are distinguished from other acanthodians by possessing dentigerous jaw bones, or gnathals, on both upper and lower jaws. Acanthodian dental elements, including dentigerous jaw bone fragments, tooth whorls, isolated single teeth and dentition cones (sensu Valiukevicius 1992) occur in shallow water, marine limestones from the upper Lochkovian/lower Pragian Trundle beds (informal geological name; Pickett 1992; Pickett and McClatchie 1991) of central New South Wales (Figure 1). Isolated scales of at least four acanthodian species (Burrow in press) have been reported from these same beds. This material comprises rare scales of the climatiid Nostolepis striata and Machaeracanthus sp. (Acanthodii incertae sedis), and abundant scales of a new species (Burrow in press) and "Nostolepis" guangxiensis Wang, both of which might be ischnacanthids. Few systematic descriptions of Australian Early Oevonian acanthodian microremains have been published; Gross (1971a) described a small collection of acanthodian scales from Wilson's Cliffs, Western Australia, but the paucity and poor preservation of the material precluded classifying the scales. Long (1986) described small ischnacanthid gnathal bones of two types from the Emsian Spirifer yassensis and Cavan Bluff Limestones, Murrimbidgee Group, near Taemas, New South Wales, and from the uppermost Emsian Rocky Camp member, Murrindal Limestone, Buchan Group of Victoria. He assigned the bones to two separate genera, Taemasacanthus and Rockycampacanthus (Figure 2A-C) respectively. Turner (e.g., 1991) has recorded many occurrences of acanthodian scales, and has also reported occurrences of dental elements (e.g., Turner 1991, plate 2, fig. 0). Worldwide, a number of ischnacanthid taxa have been described based on isolated dentigerous jaw bones; only a small number (Ischnacanthus gracilis, Uraniacanthus spinosus and Poracanthodes menneri) are based on descriptions of articulated fish. Assigning the gnathal bones to the upper or lower jaw is often not possible, as only rarely is the posterior end preserved with the dentigerous area. Moreover, in the taxa based on articulated specimens, the upper and lower dentigerous zones are identical. The present paper describes the acanthodian dental elements found in the Trundle beds samples, including two previously undescribed elements a denticulated plate plus toothwhorl, and the posterior end of a probable upper jaw gnathal. An attempt is made to elucidate the dental patterns of the acanthodian fish from which the elements derive, and the affinities of these taxa are discussed. MATERIAL The specimens described in this study are from limestone samples collected and treated with acetic acid by Or John Pickett (Geological Survey of New South Wales), and subsequently picked for microvertebrates by Or Susan Turner (Queensland Museum) and the author. The samples are from