Fig. 16

Harriotta raleighana (Rhinochimeridae; Holocephali; Chondrichthyes). Juvenile and adult dental plates, μCT-scans density-rendered to expose rods, ovoid and tritors. a, b juvenile upper and lower dental plates, with rods (rod), ovoids (ov) and developing tritor (tri). d, e dental plates density-rendered showing (D), elongate hypermineralized dentine rods more rostral labially in the upper dental plate, with a row of ovoids and rods parasymphyseally and two series of ovoids among the series of rods; in the more caudal plate, ovoids and a developing tritor are present. c, f lower jaw from younger individual, indicated by less well-developed tritor and longer rods rostrally. g–l adult upper dental plates. h density-render showing ovoids dominant in rostral plate, ovoids and tritor in more caudal plate. i virtual section through rostral dental plate, showing elongate spaces developing within the trabecular dentine (td). j–l density-rendered rostral plate in j oral, k symphysial, l symphysial (rotated) view. Small white arrows indicate rods of dentine developing caudally. l Most caudal rod appears paired, possibly due to failure of spaces in trabecular dentine to form properly. Asterisk (A–C, G) indicates jaw furrow in which dental plate develops. Scale bar C = 0 .5cm, G, I = 1 cm, J–L = 0.25 cm