Comparison of the tibiotarsi of hesperornithiforms in cranial view (left-to-right: <i>Fumicollis hoffmani</i> UNSM 20030; <i>Parahesperornis alexi</i> KUVP 2287; <i>Hesperornis regalis</i> YPM 1200; <i>Baptornis advenus</i> AMNH 5101).

1, arrow indicates the medial expansion of the distal end, seen to the greatest degree in F. hoffmani and P. alexi. 2, arrows indicate the discrepancy in distal extent of the medial and lateral condyles in F. hoffmani and B. advenus. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: es, extensor sulcus; lc, lateral condyle; mc, medial condyle; t, tubercle retinaculi m. fibularis.