Crivadiatherium iliescui, Radulesco & Sudre, 1985

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 : 621

CRIVADIATHERIUM ILIESCUI

In a vertical section of a molar fragment, the enamel is around 1400-µm thick. The Schmelzmuster is twolayered with radial enamel in the outer zone underlain progressively by modified radial enamel in the inner first-third ( Fig. 6E ). In modified radial enamel ( Pfretzschner, 1994), the IPM forms vertical large sheets between radial rows of prisms; the prisms are lanceolate in outline and the crystallites of the IPM are directed perpendicular to the long axis of the prisms. On a horizontal section of the same specimen, the diameter of the prisms is around 5–10 µm in the outer zone; their cross sections are typically rounded and the amount of IPM is important around prisms.

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.