Figure 6. A in Evolution of the tooth enamel microstructure in the earliest proboscideans (Mammalia)

Figure 6. A, Numidotherium koholense, early Eocene, El Kohol, Algeria; vertical section of a lower molar showing zones of transition between areas of decussations; the prisms exhibit a keyhole cross section and the interprismatic matrix (IPM) is very reduced. B, Numidotherium savagei, late Eocene, Dor el Talha, Libya; vertical section of a lower molar with 3-D enamel near the enamel dentine junction (EDJ). C, Anthracobune pinfoldi, either late early or early middle Eocene, Kuldana Formation, Pakistan; horizontal section of a P4 near the outer enamel surface (OES), closed circles within hexagonal structures are typical of poorly mineralized areas of the outer zone; the hexagons represent the area of one ameloblast and the central circles may represent the trace of Tomes' process. D, Seggeurius amourensis, early Eocene, El Kohol, Algeria; natural vertical section of an upper molar with a Schmelzmuster composed of radial enamel only. E, Crivadiatherium iliescui, late Eocene, Hateg Basin, Romania; vertical section of a molar showing modified radial enamel in the inner first-third of the enamel thickness; in this zone, the prisms are lanceolate in outline and the crystallites of the IPM are directed perpendicular to the prisms long axis.