Fig. 3. Mesosaurid parareptile Stereosternum tumidum Cope, 1886 in Tooth microstructure of the Early Permian aquatic predator Stereosternum tumidum

Fig. 3. Mesosaurid parareptile Stereosternum tumidum Cope, 1886 from Passo do São Borja outcrop, Irati Formation, Lower Permian of the Paraná Basin; UFRGS-PV-0378-P. A. Close view of the tooth attachment complex (the tooth wall is at the left). An anchorage trabecula is indicated, partly composed of avascular cementum and partly of alveolar bone. It is also possible to individualize the layers of orthodentine, externalmost vasodentine and interglobular dentine (at the right). B. Schematic drawing ofA. C. Detail of an anchorage trabecula, viewed in reflected light optical microscopy. Abbreviations: ab, alveolar bone; ce, cementum; igd, interglobular dentine; od, orthodentine; tr, anchorage trabecula; vc, vascular canalicle; vd, vasodentine.