Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds
Fig 4
Photographs and interpretative drawings of presacral vertebrae 16 (A) and 17 (B) of UNSM 20030 in dorsal (1), cranial (2), lateral (3), caudal (4), and ventral (5) views.
Abbreviations: ca, caudal articular surface; cf, costal fovea; cr, cranial articular surface; lc, lateral concavity; ns, neural spine; poz, postzygapophysis; prz, prezygapophysis; tp, transverse process; vp, ventral process.