Palawan Hornbill, adult male
<bdi><a href="https://en.wikipedia.org/wiki/en:John_Gerrard_Keulemans" class="extiw" title="w:en:John Gerrard Keulemans"><span title="Dutch bird artist (1842-1912)">John Gerrard Keulemans</span></a>
</bdi>
1885
<i>Proceedings of the Zoological Society of London</i> (<a rel="nofollow" class="external text" href="https://archive.org/details/proceedingsofgen85zool">vol. 1885</a>, <a rel="nofollow" class="external text" href="https://archive.org/stream/proceedingsofgen85zool#page/n528/mode/1up">plate XXVI</a>)