Specimen completeness among reported hesperornithiforms.

The number of specimens preserving fewer than three elements (black) and three elements or more (red) are shown for all described hesperornithiform taxa. A schematic reconstruction of UNSM 20030 is shown with the preserved elements shaded dark gray. It should be noted that the exact rib placement is not known and was estimated for the figure. References for hesperornithiform taxa are as follows: Baptornis advenus [11, 6]; Asiahesperornis bazhanovi [25]; Brodavis [26]; Canadaga arctica [17, 27]; Enaliornis [28]; Hesperornis crassipes, H. gracilis [11]; H. bairdi, H. chowi, H. macdonaldi, H. mengeli [29]; H. regalis [11, 30–31]; H. rossicus [32]; Judinornis nogontsavensis [33]; Parahesperornis alexi [15]; Pasquiaornis spp. [34–36]; Potamornis skutchi [37].