Lopez de Bertodano Formation

From Wikipedia, the free encyclopedia
Jump to: navigation, search
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 undisputably 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.

Undescribed euornithopod[2]

Unnamed species[2]

Undescribed hadrosaurid[1]

Unnamed species

Isolated tooth[1]

Undescribed theropod[1]

Unnamed species

Fragments[1]

See also[edit]

References[edit]

  1. ^ a b c d e 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. ^ a b c d e 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