FIG. 18. — Nostolepis decora n in Devonian acanthodians from Severnaya Zemlya Archipelago (Russia)

FIG. 18. — Nostolepis decora n. sp., histologic structure of trunk scales, tesserae-scales and denticled branchial? plates; A, normal trunk scale (like figured on Fig. 17G) in anise oil, crown, LIG 35-2077; B, tessera-scale (see Fig. 17H) in anise oil, crown, LIG 35-2076; C, vertical longitudinal section through the central part of scale with posteriorly pointed elongated crown (see Fig. 17C), thin section 3447; D, vertical transverse section through the anterior part of stretched scale with linked upward, notched lateral areas (see Fig. 17F), thin section 3449; E, slightly recurved denticled plate in anise oil, LIG 35-2075; F, vertical longitudinal section through the asymmetrical tessera-scale from the lateral line, thin section 3448. For locality and stratigraphic assignement see Fig. 17. Abbreviations: avc, ascending vascular canal; cbo, cellular bone; cvc, circular vascular canal; oc, osteocyte cavity; rvc, radial vascular canal; smd, simple mesodentine; stg, Stranggewebe (oriented mesodentine). Scale bars: 0.1 mm.