FIG. 10. — Acritolepis ushakovi n. gen., n in Devonian acanthodians from Severnaya Zemlya Archipelago (Russia)

FIG. 10. — Acritolepis ushakovi n. gen., n. sp., scale histology, from paratype LIG 35-A-404, Spokojnaya River, outcrop 41, bed 12, Severnaya Zemlya Formation; A, vertical longitudinal section through the asymmetrical trunk scale (see Fig. 5K), thin section 3359; B, vertical transverse section through the central part of small elongated tail scale (see Fig. 5J), thin section 3363; C, D, vertical longitudinal sections through the central part of trunk (C, thin section 3355) and tail scale (D, thin section 3358); E, vertical transverse section through the head scale (see Fig. 5H), thin section 3360; F, vertical longitudinal section through the less ornamented (with two short ridgelets) trunk scale, thin section 3357. Abbreviations: cbo, cellular bone; cvc, circular vascular canal; dd, durodentine; gl, growth lamella; lsh, longitudinal Sharpey's fibres; md, mesodentine; oc, osteocyte cavity; sqsh, transverse Sharpey's fibers; stg, Stranggewebe (oriented mesodentine). Scale bar: 0.1 mm.