Figure 1.Roadside exposure from which specimens were collected: A, map showing the location of LaSalle County within Illinois and the location of the exposure (star); B, view of the locality; C, the exposure of the LaSalle Limestone Member, Bond Formation. All teeth were collected from the talus at the base of the exposure.Photos by RG.
The journal Kentiana has a paper about fossil shark teeth from the Bond Formation in northern Illinois. The title of the paper is "First records of the chondrichthyans Heslerodus and Ossianodus from the Upper Pennsylvanian LaSalle Limestone (Bond Formation) of northern Illinois". Kentiana is an open access journal associated with the Center for Paleontology, the Illinois Natural History and State Geological surveys, and academic departments at the University of Illinois at Urbana-Champaign.
Abstract
Heslerodus divergens and an undetermined species of the genus Ossianodus are recorded for the first time from the Upper Pennsylvanian LaSalle Limestone Member of the Bond Formation in northern Illinois. Ossianodus is a new record for the state. Four specimens of H. divergens and one of Ossianodus sp. were recovered, all partially complete teeth. Descriptive and comparative notes are provided. Future studies of the formation may yield additional specimens of other vertebrate species.
Keywords
Heslerodus, Ossianodus, Chondrichthyes, Elasmobranchii, sharks, LaSalle County
Introduction
The shark species Heslerodus divergens (Ctenacanthiformes: Heslerodidae) is known from Pennsylvanian deposits across North America and Russia, including teeth, fin spines, and skeletal elements (Ginter 2002). In July of 2020, the senior author collected two teeth at an exposure of the Upper Pennsylvanian LaSalle Limestone Member of the Bond Formation near Oglesby, LaSalle County, Illinois (Figure 1). Subsequent visits to the site yielded several more H. divergens teeth and a single tooth assigned to the genus Ossianodus (Hybodontiformes: Hybodontidae). These specimens represent the first records of these species from the highly fossiliferous LaSalle Limestone Member and, in addition to being previously unknown from the LaSalle Limestone, this is also the first record of Ossianodus from Illinois.
