Bifid neck feather of Spilopelia chinensis
Charles Otis Whitman (December 14, 1842 – December 6, 1910) - delineator given as Hayashi (dates unknown)
1919
<a rel="nofollow" class="external text" href="https://archive.org/stream/posthumousworks01whituoft#page/n132/mode/1up">Orthogenetic evolution in pigeons</a>