C4-P-07Analysis of fine three-dimensional structure of pharyngeal teeth of saury (Cololabis saira: ‘SAMMA’), flying fish (Cypselurus pinnatibarbatus japonicus: ‘TOBIUO'), medaka (Oryzias latipes), zebrafish (Danio rerio), and other teleost species by X-ray micro-computed tomography

Abstract

Many teleosts not only have teeth on the jaws but also in the pharynx called ‘pharyngeal teeth’. We studied the detailed structure of the pharyngeal teeth in several teleost species by mCT at SPring-8 (BL20B2/20XU/47XU; 2014A1475/B1541/B1568/B1377; 0.2∼6.5μm resolution). Saury and flying fish were found to possess a large number of pharyngeal teeth with a similar arrangement as medaka. However, while the morphology of the individual tooth is uniform in medaka, the ones in saury and flying fish are highly diverged from cone, spindle, 3-5 lobate leaf to mushroom-shape, dependent on the places and species. As the first step to understand the developmental mechanism to create such divergence, we analyzed the internal structure of each tooth of saury, medaka and zebrafish, revealing numerous fine ducts inside of dentin extending toward enamel, whose pattern may be correlated with the difference in the tooth shape. Supported by the grant for special educational research in Univ. of Hyogo.