Fig. 8

Harriotta raleighana (Rhinochimeridae; Holocephali; Chondrichthyes). Discontinuity in tritor of caudal part, upper plate reflected and transmitted light with BSE. a, b, optical micrographs, c–f, BSE of polished section as scanning electron micrographs. A incident reflected light (× 6.5), labial ovoids alongside lingual tritor with distinct disjunct region below the functional tritoral region (white arrows), including fields shown in B and Fig. 11c. b tissue details shown with transmitted light, masses of tubules (asterisk) and dense light-obstructive areas, below line indicating disjunct region (black arrows). c below disjunct line (white arrows) very low mineralization, separated from the high mineral density above. This line does not cross into outer dentine (od) at lingual surface. d, e disjunct line (white arrows) with tubule masses below, high mineral density above, higher magnifications of fields (D, F) shown in E. d tubules (tu) below the disjunction, and fewer above in the high mineral density region. e pre-mineralized ovoid spaces (ov) adjacent to mineralized tritor (tri) with dentine lining vascular tubes (vt). f chaotic tubules, multiple sizes, with vesicles and saccules (compare with Fig. 9). Scale bars A = 0 .5mm; B, C, E, F = 100um; D = 30 μm