FIG. 32. — Watsonacanthus costatus n in Devonian acanthodians from Severnaya Zemlya Archipelago (Russia)

FIG. 32. — Watsonacanthus costatus n. sp., scale histology, Pioneer Island, sample P-10-1, Lower Devonian, Member 8; A-C, vertical longitudinal sections of scales, anterior to left, thin sections 3289 (A, scale like figured on Fig. 23K), 3302 (B, scale with shorter ridges) and 3303 (C, scale like figured on Fig. 23H); D, vertical transverse section through the central part of scale like figured on Fig. 23K. Abbreviations: avc, ascending vascular canal; cbo, cellular bone; dt, dentine tubule; gl, growth lamella; oc, osteocyte cavity; rvc, radial vascular canal; smd, simple mesodentine. Scale bar: 0.1 mm.