Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds
Fig 24
Comparison of the tarsometatarsi of hesperornithiforms (left-to-right: Fumicollis hoffmani UNSM 20030; Parahesperornis alexi KUVP 2287; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101; Brodavis varneri SDSM 68430).
A, dorsal view, relative widths (arrows, 1) and distal extents (2) of metatarsals III and IV. B, distal view, arrangement of the metatarsal trochleae, with arrow (3) indicating spacing between the trochleae of metatarsals III and IV. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: II–IV, trochlea of metatarsals II–IV.