Los Alamitos Formation

The Los Alamitos Formation is a geological formation of the North Patagonian Massif in Rio Negro Province, northwestern Patagonia, Argentina, whose strata date back to the Late Cretaceous (Late Campanian to Maastrichtian). Dinosaur remains are among the fossils that have been recovered from the formation.[1]

Los Alamitos Formation Stratigraphic range: Late Campanian-Maastrichtian ~85–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Coli Toro Member
Lithology
Primary	Siltstone
Other	Sandstone
Location
Coordinates	42.1°S 66.3°W
Approximate paleocoordinates	45.0°S 52.3°W
Region	Río Negro Province
Country	Argentina
Extent	North Patagonian Massif
Los Alamitos Formation (Argentina)

Fossil content

Paleogeography of the Late Cretaceous with Los Alamitos Formation indicated

Dinosaurs

Non-avian dinosaurs reported from Los Alamitos Formation
Genus	Species	Material	Notes	Images
Aeolosaurus	A. rionegrinus
Secernosaurus (="Kritosaurus" australis)	S. koerneri	"Partial skulls with associated postcrania, approximately [five] individuals."	[2][3]
Indeterminate theropod

Birds

Birds reported from the Los Alamitos Formation
Genus	Species	Material	Notes	Images
Alamitornis	A. minutus
cf. Hesperornithes
Indeterminate Ornithurine
Indeterminate Avian

Mammaliaforms

Mammaliaforms reported from the Los Alamitos Formation
Genus	Species	Material	Notes	Images
Alamitherium	A. bishopi		[4]
Austrotriconodon	A. sepulvedai A. mckennai
Leonardus	L. cuspidatus
Bondesius	B. ferox
Brandonia	B. intermedia
Casamiquelia	C. rionegrina
Ferugliotherium	F. windhauseni
Gondwanatherium	G. patagonicum
Groebertherium	G. novasi
Mesungulatum	M. houssayi		[5]
Paraungulatum	P. rectangularis
Reigitherium	R. bunodontum		[6]
Rougiertherium	R. tricuspes

See also

• List of dinosaur-bearing rock formations

References

1. Weishampel et al., 2004, "Dinosaur distribution (Late Cretaceous, South America).", pp.600-604
2. Prieto–Marquez, Alberto; Salinas, Guillermo C. (2010). "A re–evaluation of Secernosaurus koerneri and Kritosaurus australis (Dinosauria, Hadrosauridae) from the Late Cretaceous of Argentina". Journal of Vertebrate Paleontology. 30 (3): 813–837. doi:10.1080/02724631003763508.
3. "Table 20.1," in Weishampel, et al.
4. Bonaparte, 1999
5. Bonaparte & Soria, 1985
6. Bonaparte, 1990

Bibliography

• Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2