FIG. 16. — Acritolepis urvantsevi n. gen., n in Devonian acanthodians from Severnaya Zemlya Archipelago (Russia)

FIG. 16. — Acritolepis urvantsevi n. gen., n. sp., histology of scales, all scales from the holotype (LIG 35-A-382), Pod"emnaya River, outcrop 67, bed 12, Severnaya Zemlya Formation; A, vertical longitudinal section through the tessera-scale with multiangular base, thin section 3351; B, vertical longitudinal section through the elongated trunk scale, thin section 3348; C, vertical transverse section through the central part of normal trunk scale, thin section 3347; D, magnified area of the primordial growth lamella of the same scale; E, vertical transverse section through the anterior part of tessera-like scale with quadrangular base, thin section 3349; F, vertical longitudinal section through the normal trunk scale, thin section 3350. Abbreviations: avc, ascending vascular canal; cbo, cellular bone; dt, dentine tubule; gl, growth lamella; oc, osteocyte cavity; rvc, radial vascular canal; smd, simple mesodentine; stg, Stranggewebe (oriented mesodentine). Scale bars: 0.1 mm.