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Pteraspidomorphi (Ordovician). Odontode-like tubercles of various pteraspidomorphs presented as schematics (A–C) and original (D–F) sections. (A,B,D) Astraspis, (C,E,F) Eriptychius, demonstrating the various combinations of enameloid, orthodentine and acellular bone. Scale bars: D = 100 µm; E = 150 µm; F = 50 µm.
