FIG. 39 in Devonian acanthodians from Severnaya Zemlya Archipelago (Russia)

FIG. 39. — Poracanthodes sp. cf. P. subporosus Valiukevicius, 1998, scale and spine histology, from paratype LIG 35-A-376, Spokojnaya River, outcrop 41, bed 12, Severnaya Zemlya Formation; A, vertical longitudinal section through the central part of scale with pore canal openings on the posterior crown half, anterior to left, thin section 3465; B, vertical transverse section through the central part of scale with pore canal openings on the extreme posterior part only, thin section 3467; C, D, transverse sections through the unidentified fin spines, thin sections 3471 (C) and 3470 (D). Abbreviations: abo, acellular bone; arcpc, arcade pore canal; avc, ascending vascular canal; dd, durodentine; dt, dentine tubule; lvc, longitudinal vascular canal; oc, osteocyte cavity; os, osteon; po, pore opening; rpc, radial pore canal; smd, simple mesodentine. Scale bar: 0.1 mm.