Prochilodus lineatus (Valenciennes)

Scharcansky, Alexandre & Lucena, Carlos Alberto S., 2008, Phylogenetic assessment of ultrastructural and histological characters of teeth in the Anostomoidea, Hemiodontidae and Parodontidae (Teleostei: Ostariophysi: Characiformes), Zootaxa 1948 (1), pp. 36-56 : 42

Prochilodus lineatus (Valenciennes) ( Figs. 8 and 9 )

No bone tissue was identified close to the rows of functional teeth. The replacement teeth are arranged away from the functional row and comprise groups somewhat organized. Each set is enclosed by connective and adipose tissues. The posterior teeth show an earlier development stage when compared to more anterior teeth, and are aligned differently with respect to the functional teeth. Therefore, they show a pre-eruptive rotation. Histologically, the replacement teeth in their final stage show a pattern similar to the functional teeth from the exterior inwards: a narrow enamel layer (light area of tooth, see Figure 9C ), demineralized due to the histological preparation process, is surrounded by elongated ameloblasts. Next is the dentin layer. It was not possible to detect the odontoblasts in the sections analyzed. Starting from the enamel layer we see conspicuous periodontal ligaments already fully developed. Finally, the dental papilla (mesenchymal cells) forms an elongated or elliptical area.

The functional teeth are connected along the dentin layer to connective tissue by small periodontal ligaments. The dentin layer is evenly narrow all around the teeth. The dental pulp is restricted to the region before the horizontal line that goes through the lip-tooth connection, and bordered in the back by a thick layer of connective tissue.

Figures

FIGURE 8. Prochilodus lineatus (Valenciennes, 1836) MCP 14385, 174.89 mm SL - A: Premaxilla and teeth, left side, frontal view. B: Left premaxilla teeth, frontal view, apical region detail. C: Left premaxilla teeth, frontal view, median region. D: Left premaxilla teeth, teeth-premaxilla bone contact, frontal view. E: Premaxilla tooth, left side, SEM image showing the crystal apatite arrangement, labiolingual direction.

FIGURE 9. Prochilodus lineatus (Valenciennes, 1836) MCP 14385, 174.89 mm SL A. Dentary, cross section (10x). B and C: Replacement teeth, 10x and 40x respectively. D: Functional teeth embedded in epithelial tissue (20x). E. Dentary, cross section, showing the pre-eruptive rotations of germs of replacement teeth; arrow points the apical region of the replacement teeth. DE=dentary; DF=functional teeth; DN=dentin; DS=replacement teeth; ES=enamel; LP=periodontal ligament; PA=dental papilla; PO=pulp; TC=connective tissue; TE=epithelial tissue.