I.J. Sansom J.E. Repetski M.P. Smith 1996 <p><span>The first description of&nbsp;</span><i>Anatolepis</i><span>&nbsp;Bockelie &amp; Fortey was from early Ordovician sediments of Ny Friesland, Spitsbergen</span>^1,2<span>, but the genus is now known from many localities in North America and Greenland, ranging in age from the Late Cambrian period to the Early Ordovician</span>^3–6<span>. Although initially interpreted as an agnathan fish</span>^2,3<span>&nbsp;that predated other representatives</span>⁷<span>, this has been widely disputed because the available histological data were unconvincing</span>^6,8–10<span>&nbsp;and the scales fell outside the known morpho-logical range of other accepted early vertebrates</span>^9–11<span>. Further doubt was cast upon the vertebrate affinity of&nbsp;</span><i>Anatolepis</i><span>&nbsp;when specimens from East Greenland were interpreted as the cuticular fragments of aglaspid arthropods</span>⁶<span>, although this interpretation has also been refuted</span>¹²<span>. Here we report on the morphology and histology of large collections of&nbsp;</span><i>Anatolepis</i><span>, and demonstrate the presence of dentine, a tissue unique to vertebrates, confirming that the taxon is both a vertebrate and the oldest known fish.</span></p> application/pdf 10.1038/380702a0 en Springer Nature Histology of the first fish article