Phylogenetic assessment of ultrastructural and histological characters of teeth in the Anostomoidea, Hemiodontidae and Parodontidae (Teleostei: Ostariophysi: Characiformes) Author Scharcansky, Alexandre Animal Science and Veterinary Laboratory. Hebrew University of Jerusalém. Faculty of Agricultural, food and Environmental Quality Sciences. Rehovot 76100, Israel. E-mail: ytzhak. scharcansky @ mail. huji. ac. il Setor de Peixes. Museu de Ciências e Tecnologia da Pontifícia Universidade do Rio Grande do Sul. Av. Ipiranga 6681. 90619 - 900. Porto Alegre, Brazil. RS. E-mail: lucena @ pucrs. br Author Lucena, Carlos Alberto S. text Zootaxa 2008 2008-12-03 1948 1 36 56 https://biotaxa.org/Zootaxa/article/view/zootaxa.1948.1.2 journal article 10.11646/zootaxa.1948.1.2 1175­5334 5231341 Hemiodus ternetzi (Myers) ( Figs. 10 and 11 ) Members of this family lack dentary teeth; consequently, the information below refers to premaxillary teeth. FIGURE 5 . Leporinus reinhardti (Lütken, 1875) . MCP 17146, 82.72 mm SL – A: Dentary, cross section (10x). B: Arrows point to the apical region of replacement teeth. C: Replacement tooth (40x). D: Attachment region of functional teeth (20x). E: Dentary, cross section, detail of the tissue supporting the functional teeth. AM=ameloblasts; DE=dentary; DF=functional teeth; DN=dentin; DS=replacement teeth; ES=enamel; OD=odontoblasts; PA= dental papilla; PO=pulp; TC=connective tissue; TE=epithelial tissue; TO=bone tissue. There is no bone tissue surrounding the base of the teeth. However, we can see a compact bone formation in the posterior region of the premaxilla. The replacement teeth are arranged in six to eight sets (considering both premaxillaries), each corresponding to a functional tooth. Each set is surrounded by adipose and connective tissues. More posterior teeth show an earlier development stage when compared to more anterior teeth, and are aligned in a manner different from that of the functional teeth. Therefore, they show a pre-eruptive rotation. Histologically, the replacement teeth in their final stage show a pattern similar to that of the functional teeth from the exterior inwards: a narrow enamel layer (light tooth area, see Figure 11C ), demineralized due to the histological preparation process, is surrounded by elongated ameloblasts. Next are the dentin layer and the set of odontoblasts, comparatively narrower than the ameloblasts. Starting from the enamel layer we see conspicuous periodontal ligaments already fully developed. Finally, the dental papilla (mesenchymal cells) forms a narrow area. The functional teeth are connected along the dentin layer to the premaxilla by small periodontal ligaments. The dentin layer is equally narrow all around the teeth. The dental pulp, located after the horizontal line that goes through the bone-tooth connection, is wide and much larger than the tooth base, being bordered in the back by the column of replacement teeth.