FIG. 7. — Machaeracanthus goujeti n in Machaeracanthus goujeti n. sp. (Acanthodii) from the Lower Devonian of Spain and northwest France, with special reference to spine histology

FIG. 7. — Machaeracanthus goujeti n. sp.; Lower Devonian, Iberian Chain. Transverse section of middle part of spine MPZ 2010/958, juvenile: A, general view of upper longitudinal ridge, wing and pulp cavity; B, C, details of the hard tissues in the wing close to the central axis, showing lamellar dentine with growth increment and trabecular dentine with denteons; D, detail of centripetally growing trabecular dentine around the pulp cavity. Thin section observed in transmitted ordinary light. Abbreviations: see Material and methods Scale bars: A, 0.5 mm; B, D, 0.1 mm; C, 50 μm.