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A lithornithid (Aves: Palaeognathae) from the Paleocene (Tiffanian) of southern California

The proximal end of a bird humerus recovered from the Paleocene Goler Formation of southern California is the oldest Cenozoic record of this clade from the west coast of North America. The fossil is characterized by a relatively large, dorsally-positioned head of the humerus and a subcircular opening to the pneumotricipital fossa, consistent with the Lithornithidae among known North American Paleocene birds, and is similar in size to Lithornis celetius. This specimen from the Tiffanian NALMA extends the known geographic range of lithornithids outside of the Rocky Mountains region in the United States. The inferred coastal depositional environment of the Goler Formation is consistent with a broad ecological niche of lithornithids. The age and geographic distribution of lithornithids in North America and Europe suggests these birds dispersed from North America to Europe in the Paleocene or by the early Eocene. During the Paleogene the intercontinental dispersal of lithornithids likely occurred alongside other known bird and mammalian movements that were facilitated by climatic and sea level changes.

Paleogene chelonians from Maryland and Virginia

Fossil remains of 22 kinds of Paleogene turtles have been recovered in Maryland and Virginia from the early Paleocene Brightseat Formation (four taxa), late Paleocene Aquia Formation (nine taxa), early Eocene Nanjemoy Formation (five taxa), middle Eocene Piney Point Formation (one taxon), and mid-Oligocene Old Church Formation (three taxa). Twelve taxa are clearly marine forms, of which ten are pancheloniids (Ashleychelys palmeri, Carolinochelys wilsoni, Catapleura coatesi, Catapleura sp., Euclastes roundsi, E. wielandi, ?Lophochelys sp., Procolpochelys charlestonensis, Puppigerus camperi, and Tasbacka ruhoffi), and two are dermochelyids (Eosphargis insularis and cf. Eosphargis gigas). Eight taxa represent fluvial or terrestrial forms (Adocus sp., Judithemys kranzi n. sp., Planetochelys savoiei, cf. “Trionyx” halophilus, “Trionyx” pennatus, “Kinosternoid B,” Bothremydinae gen. et sp. indet., and Bothremydidae gen. et sp. indet.), and two taxa (Aspideretoides virginianus and Allaeochelys sp.) are trionychian turtles that probably frequented estuarine and nearshore marine environments. In Maryland and Virginia, turtle diversity superficially appears to decline throughout the Paleogene, but this probably is due to an upward bias in the local stratigraphic column toward more open marine environments that have preserved very few remains of riverine or terrestrial turtles.