Numidotherium savagei, Court, 1995

Tabuce, Rodolphe, Delmer, Cyrille & Gheerbrant, Emmanuel, 2007, Evolution of the tooth enamel microstructure in the earliest proboscideans (Mammalia), Zoological Journal of the Linnean Society 149 (4), pp. 611-628 : 616

NUMIDOTHERIUM SAVAGEI

In a vertical section of a m3 tooth, the enamel thickness is around 2400 µm. The Schmelzmuster is threelayered. The outermost zone consists of radial enamel, but a thin zone of prismless enamel can also occur. In the middle zone, which reaches almost 30% of the enamel thickness, the enamel type is formed by HSB. In the inner zone, 3-D enamel represents about 45% of the entire enamel thickness ( Fig. 6B ). The transition between the three enamel types (3-D enamel, HSB, and radial enamel) is gradual. At the prism level, the keyhole pattern, without any trace of IPM, is observed in 3-D enamel; rounded prisms characterized radial enamel; and in HSB, the prisms cross sections ranged from rounded to open. The diameter of the prisms is around 5 µm.

Figures

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.