(Figure 12.5), including Presbyornis, because of the presence of a prominent crista fossa
parabasalis of the exoccipitale (character 2 of Livezey 1997) and a prominent processus
coronoideus of the mandible (character 18 of Livezey 1997) (Figure 12.5). See Dyke
(2001b) for details.
GalliformesThe landfowl of the order Galliformes form a large and cosmopolitan group of about 70
genera (Monroe and Sibley 1990) found on almost all continents across the globe. Again,
the described fossil record of these birds is extensive—putative remains of Galliformes
have been described from deposits that range in age from the latest Cretaceous to Recent
Figure 12.5 (A) Hypothesis for the phylogenetic positions of the lower Eocene taxa Presbyornis and
Anatalavis (boldface)—well-preserved fossil representatives of order Anseriformes (see text for details
and sources); (B–D) some of the preserved elements of Anatalavis oxfordi Olson (BMNH PAL 5922):
(B) skull in lateral views; (C) furcula; (D) coracoid in dorsal and medial views. Scales are 10 mm.
BASAL RADIATIONS WITHIN THE NEORNITHES 277