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The Rayoso Formation is a geological formation in the Neuquén Province of Argentina whose strata date back to the Aptian stage of the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.[1]

Rayoso Formation
Stratigraphic range: Aptian
TypeGeological formation
Unit ofHuitrín-Rayoso Group
Sub-unitsPichi Neuquén Member
UnderliesLohan Cura & Carrín Cura Formations
OverliesLa Amarga & Huitrín Formations
Thicknessup to 604 m (1,982 ft)
Coordinates38°24′S 69°54′W / 38.4°S 69.9°W / -38.4; -69.9Coordinates: 38°24′S 69°54′W / 38.4°S 69.9°W / -38.4; -69.9
Approximate paleocoordinates40°06′S 37°30′W / 40.1°S 37.5°W / -40.1; -37.5
RegionNeuquén Province
Country Argentina
ExtentNeuquén Basin
Rayoso Formation is located in Argentina
Rayoso Formation
Rayoso Formation (Argentina)


The formation has a maximum thickness of 604 metres (1,982 ft) and has one member, the Pichi Neuquén Member. The unit comprises sandstones deposited in a lacustrine environment.[2]

Fossil contentEdit

Indeterminate ceratosaurian remains located in Neuquén Province, Argentina.[1]

Dinosaurs of the Rayoso Formation
Genus Species Presence Notes Images
Lavocatisaurus L. agrioensis Neuquén Province Specimens representing several individuals at one site, including two juveniles and an adult


See alsoEdit


  1. ^ a b Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 570-71. ISBN 0-520-24209-2.
  2. ^ 3 km south of Agrio del Medio at

Further readingEdit

  • J. F. Bonaparte. 1996. Cretaceous tetrapods of Argentina. Münchner Geowissenschaften Abhandlungen 30:73-130
  • L. Salgado, J. I. Canudo, A. C. Garrido and J. L. Carballido. 2012. Evidence of gregariousness in rebbachisaurids (Dinosauria, Sauropoda, Diplodocoidea) from the Early Cretaceous of Neuquén (Rayoso Formation), Patagonia, Argentina. Journal of Vertebrate Paleontology 32(3):603-613