TY - JOUR N2 - Here we use synchrotron tomography to characterise dental vasculature in the oldest known tooth-bearing sharks, Leonodus carlsi Mader, 1986 and Celtiberina maderi Wang, 1993. Three dimensional reconstruction of the vascular system and microstructure of both taxa revealed a complex and dense network of canals, including horizontal, ascending and secondary bifurcated canals, as well as histological features consistent with an osteodont histotype. However, L. carlsi and C. maderi also exhibit significant morphological differences, showing Leonodus a typical diplodont tooth morphology with a linguo-labially elongated base, that contrast with Celtiberina’s teeth that show a single conical cusp curved lingually with a week developed flat base mesio- distally extended, perhaps reflecting distant relationship. These data are compatible with a pre-Devonian diversification of the two main tooth types traditionally recognised in Palaeozoic sharks (i.e., “cladodont” vs “diplodont”). Finally, our data demonstrate that existing dental classification schemes based on styles of vascularisation are over-simplified, especially when Palaeozoic taxa are considered. L1 - http://journals.pan.pl/Content/108915/PDF-MASTER/13_Martinez-Perez.pdf L2 - http://journals.pan.pl/Content/108915 PY - 2018 IS - No 3 EP - 457–465 KW - Leonodus KW - Celtiberina KW - Early chondrichthyans KW - Lower Devonian KW - Synchrotrontomography KW - Vascular system A1 - Martínez-Pérez, Carlos A1 - Martín-Lazaro, Alba A1 - Ferrón, Humberto G. A1 - Kirstein, Martina A1 - Donoghue, Philip C.J. A1 - Botella, Hector PB - Komitet Nauk Geologicznych PAN PB - Wydział Geologii UW VL - vol. 68 DA - 2018.10.01 T1 - Vascular structure of the earliest shark teeth SP - 457–465 UR - http://journals.pan.pl/dlibra/publication/edition/108915 T2 - Acta Geologica Polonica ER -