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Fig. 11 | Zoological Letters

Fig. 11

From: Growth and mineralogy in dental plates of the holocephalan Harriotta raleighana (Chondrichthyes): novel dentine and conserved patterning combine to create a unique chondrichthyan dentition

Fig. 11

Harriotta raleighana (Rhinochimeridae; Holocephali; Chondrichthyes). Comparison of same partially mineralized ovoids, in μCT and optical microscopy, upper caudal dental plate. A BSE from field in C, photomicrograph in incident reflected light of the ovoids (ov) and tritor (tr) at oral surface, the same partially mineralized ovoid (*) is presented in four different modes of visualization (a, c–e), field in Fig. 8a. b BSE, aboral to A, ovoids (ov) lacking mineralization and dentine tubules, tritor with differential mineralization of hypermineralized dentine more orally, but less mineralization aborally. d, e photomicrographs in polarized light, E with gypsum plate added, ovoids at angle of 45° to polarisers, shows strong birefringence of trabecular dentine (td) (NE blue, NW yellow in quadrants between polarizer and analyzer); note in D most mineralized ovoids and tritor are weakly birefringent, but as linear birefringence at right angles to each other and with very faint blue and yellow (gypsum plate inserted at 45° to P and A data not shown), whereas ovoid with * is not birefringent, indicating a major change in form of mineralization. f Nomarsky optics, ovoid with an opaque area (black) similar to *, within the sclerotic dentine (sod, close to worn surface at far right) that is at the same mineral phase as ovoids marked by *, but tubules (tu) are visualized in the mineralized part by this method. Scale bar A, B, C, =100 μm; D, E, F = 50 μm

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