Cerro Barcino Formation

Cerro Barcino Formation Stratigraphic range: Hauterivian–Campanian
Type	Geological formation
Unit of	Chubut Group
Sub-units	Puesto Manuel Arce Bayo Overo Las Plumas Cerro Castaño La Paloma
Underlies	La Colonia Formation, Paso de Sapo Formation, Lefipan Formation
Overlies	Los Adobes Formation
Location
Region	Chubut Province
Country	Argentina

The Cerro Barcino Formation (also known as the Gorro Frigio Formation) is a geological formation in South America whose strata span the mid-late Cretaceous period. Dinosaur remains are among the fossils that have been recovered from the formation.^[1]

The Cerro Barcino Formation is the upper unit of the Chubut Group, which also includes the older Los Adobes Formation. Both formations cover a vast area in Chubut Province, Argentina. The two formations are distinguished by geological features suggesting a distinct change in climate, from a wetter, flood plain environment in the Los Adobes to a much more arid, desert-like environment in the Cerro Barcino.^[2]

The Cerro Barcino Formation is subdivided into several subunits ("members").^[2] From oldest to youngest:

• La Paloma
  • Characterized by arid plains interspersed with sand dunes
• Cerro Castaño
  • A return to more humid, flood-plain conditions
• Las Plumas
• Bayo Overo
• Puesto Manuel Arce

The final three members are likely Albian to Campanian in age (112 to 83 million years ago), while the La Paloma may date to the latest Hauterivian (130ma).^[2]

Fauna

Indeterminate abelisaurid remains.^[1] Possible indeterminate carcharodontosaurid remains.^[1] Indeterminate Titanosauria remains.^[1] Also, an unnamed titanosauriform.^[1]

Crurotarsans

Color key Taxon Reclassified taxon Taxon falsely reported as present Discredited taxon Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative data are in small text; crossed out data are discredited.

Crocodylomorphs of the Adamantina Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Barcinosuchus[3]	B. gradilis	Near El Escorial village, Chubut Province.	Cerro Castaño Member.	"Skull, mandible, and postcranial remains."	A peirosaurid. The first crocodyliform from the Chubut Group.

Dinosaurs

Dinosaurs of the Cerro Barcino Formation
Genus	Species	Presence	Material	Notes	Images
Chubutisaurus	Chubutisaurus insignis	Present in the Bayo Overo Member.[citation needed]	"[Two] partial skeletons including most limb elements and caudal vertebrae."[4]	A titanosaur.[1]	Genyodectes
Genyodectes	Genyodectes serus	Present in the Cerro Castaño Member.[5]	"Premaxillae, partial dentaries."[6]	A possible ceratosaurid.
"Megalosaurus"	"Megalosaurus" inexpectatus			Indeterminate remains originally described as a species of Megalosaurus.[1]
Tyrannotitan	Tyrannotitan chubutensis	Present in the Cerro Castaño Member.		A carcharodontosaurid.[7]

See also

• List of dinosaur-bearing rock formations

References

	Earth sciences portal
	Paleontology portal
	Dinosaurs portal

1. ^ ^{a b c d e f g} 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. 563-570. ISBN 0-520-24209-2.
2. ^ ^{a b c} Rauhut, O.W.M., Cladera, G., Vickers-Rich, P. and Rich, T.H. (2003). "Dinosaur remains from the Lower Cretaceous of the Chubut Group, Argentina." Cretaceous Research, 24(5): 487-497. doi:10.1016/S0195-6671(03)00067-3
3. ^ Juan Martín Leardi and Diego Pol (2009). "The first crocodyliform from the Chubut Group (Chubut Province, Argentina) and its phylogenetic position within basal Mesoeucrocodylia". Cretaceous Research 30 (6): 1376–1386. doi:10.1016/j.cretres.2009.08.002. 
4. ^ "Table 13.1," in Weishampel, et al. (2004). Page 268.
5. ^ Rauhut, O.W.M. (2004). Provenance and anatomy of Genyodectes serus, a large-toothed ceratosaur (Dinosauria: Theropoda) from Patagonia. Journal of Vertebrate Paleontology 24(4):894-902.
6. ^ "Table 3.1," in Weishampel, et al. (2004). Page 50.
7. ^ Novas, F. E.; S. de Valais, P. Vickers-Rich, and T. Rich (2005). "A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids". Naturwissenschaften 92 (5): 226–230. doi:10.1007/s00114-005-0623-3. PMID 15834691.