Fig. 5 in Diversity of tissues in acanthodians with Nostolepis-type histological structure

Fig. 5. Fifth type of Nostolepis histological structure, with cellular unipolar mesodentine in crowns and cellular bone in scale bases showing the first and second order growth lines. A. Fecundosquama basiglobosa (Valiukevičius 2004: fig. 5A, B); LIGG, thin section 3683. Thin−lamellar deep base and low crown both of superpositional growth (A1) and rounded osteocyte cells in crowns without processe connections and unipolar outwardly emanated dentinal tubules (A2). B. Tchunacanthus obruchevi (Karatajūtė−Talimaa and Smith 2003: fig. 18B); LIGG, thin section 1333. The short unipolar dentinal tubules in a scale crown with areal growth zones and a base which continued growing after crown growth stopped. Outcrop 135, Tchuna River, southern Siberia, upper Llandovery, Silurian. Scale bars 0.1 mm.