Lower Permian (Artinskian) chondrichthyan tooth remains (Petalodontidae) from Dovje (Karavanke Mts., NW Slovenia)

Abstract

Fossil remains of chondrichthyan tooth bases (roots) were found in Lower Permian beds exposed along the forest road between Dovje and Plavški Rovt. These layers are part of the clastic development of the Trogkofel Group beds. They are composed of an alternation of dark to light-grey shales, siltstone, and sandstone with rare beds of the conglomerate. Within the clastic succession, layers or lenses of dark-grey to black limestones (biosparitic, biomicritic and oolitic) and limestone breccias occur. The limestone consists remains of algae, fusulinids, brachiopods, and mostly crinoids (Palermocrinus and Entrochus). Detail study has shown that two remains of tooth bases belong to the genus Petalodus, one of them to the species Petalodus ohioensis. The bases are tongue-shaped and come to a rounded point in the distal (base end) edge. On the surface of the base, the typical oval-shaped foramina are visible. In addition, the osteodentine is visible on the cross-section of one specimen. Teeth of Petalodus are often the most common chondrichthyan fossil vertebrate remains reported from the Carboniferous and Permian rocks of the USA, Europe, and Russia. In Slovenia, Petalodus ohioensis has been recorded only from Upper Carboniferous beds. The new record of Lower Permian remains contributes to the knowledge of this cosmopolitan but still common genus of Late Paleozoic chondrichthyans.