Lopez de Bertodano Formation

Lopez de Bertodano Formation Stratigraphic range: Maastrichtian 70 to 66 Ma
Type	Geological formation
Unit of	Marambio Group
Overlies	Snow Hill Island Formation
Lithology
Primary	siltstone, mudstone
Other	concretion, sandstone
Location
Region	James Ross Island group, Antarctica

The Lopez de Bertodano Formation is a geological formation in the James Ross archipelago of the Antarctic Peninsula. The strata date to the end of the Late Cretaceous (upper-lower Maastrichtian stage^[1]), about 70-66 million years ago. Dinosaur remains are among the fossils that have been recovered from the formation^[2] and include at least two and probably as much as six lineages of indisputably modern birds: one related to waterfowl, a primitive shorebird or related form, 1-2 species of possible loons, a large and possibly flightless bird belonging to a lineage extinct today as well as a partial skull that might belong to either of the smaller species or represent yet another one.

Dinosaurs of the Lopez de Bertodano Formation
Genus	Species	Unit	Material	Notes	Images
Polarornis[2]	P. gregorii[2]	Lower Sandwich Bluff Member	Partial skull and skeleton, holotype	A loon?
	P.? sp.	Lower Sandwich Bluff Member	Partial skeleton including wing and hindlimbs	Possibly a more primitive form with strong flight ability and lighter bones
Vegavis	V. iaai[3]	Lower Sandwich Bluff Member	Partial skeleton, holotype	An anseriform
Undescribed Cariamae[4]	Unnamed species	Cape Lamb Member	Isolated femur	Close relative of cariamids and phorusrhacids
Undescribed charadriiform[5]	Unnamed species	Cape Lamb Member	Partial skeleton
Unidentified Neornithes[6]	Unnamed species		Partial skull	Relationships undetermined, cranium some 5–6 cm long.
Morrosaurus[7]	M. antarcticus[7]
Undescribed hadrosaurid[1]	Unnamed species		Isolated tooth[1]
Undescribed non-avian theropod[1]	Unnamed species		Fragments[1]

See also

• List of dinosaur-bearing rock formations

References

1. Olivero, E.B., Ponce, J.J., Marsicano, C.A. and Martinioni, D.R. (2007). "Depositional settings of the basal Lopez de Bertodano Formation, Maastrichtian, Antarctica." Revista de la Asociación Geológica Argentina, 62(4): 521-529.
2. Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Antarctica)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. p. 606. ISBN 0-520-24209-2.
3. Clarke, J.A., Tambussi, C.P., Noriega, J.I., Erickson, G.M. and Ketcham, R.A. (2005). "Definitive fossil evidence for the extant avian radiation in the Cretaceous." Nature, 433: 305-308. DOI:10.1038/nature03150 PDF fulltext Supporting information
4. Case, J., Reguero, M., Martin, J. and Cordes-Person, A. (2006). "A cursorial bird from the Maastrictian of Antarctica." Journal of Vertebrate Paleontology, 26(3): 48A.
5. Cordes, (2002). "A new charadriiform avian specimen from the Early Maastrichtian of Cape Lamb, Vega Island, Antarctic Peninsula". Journal of Vertebrate Paleontology, 22(3): 46A.
6. NUEVOS RESTOS DE DINOSAURIA DEL CRETÁCICO DE LAS ISLAS JAMES ROSS Y MARAMBIO, PENÍNSULA ANTÁRTICA
7. Sebastián Rozadilla, Federico L. Agnolin, Fernando E. Novas, Alexis M. Aranciaga Rolando, Matías J. Motta, Juan M. Lirio and Marcelo P. Isasi (2016). "A new ornithopod (Dinosauria, Ornithischia) from the Upper Cretaceous of Antarctica and its palaeobiogeographical implications". Cretaceous Research. in press. doi:10.1016/j.cretres.2015.09.009.