Bajo Barreal Formation

The Bajo Barreal Formation is a geological formation in the Golfo San Jorge Basin of Chubut and Santa Cruz, Argentina whose strata date back to the Middle Cenomanian to Late Turonian. The formation was first described by Teruggi & Rossetto in 1963.[1] The sandstones, claystones, mudstones, conglomerates and tuff were deposited in a fluvial environment.[2] The upper part of formation is laterally equivalent to the Yacimiento El Trébol and Meseta Espinosa Formation and the lower part to the Laguna Palacios, Cañadón Seco and Comodoro Rivadavia Formations. The Bajo Barreal Formation is a reservoir rock in the Golfo San Jorge Basin.[3]

Bajo Barreal Formation Stratigraphic range: Mid Cenomanian-Late Turonian ~97–90 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Chubut Group
Underlies	Lago Colhué Huapí Formation
Overlies	Castillo Formation
Lithology
Primary	Sandstone
Other	Claystone, mudstone, conglomerate, tuff
Location
Coordinates	45.3°S 69.6°W / -45.3; -69.6
Approximate paleocoordinates	51.6°S 46.7°W / -51.6; -46.7
Region	Chubut, Santa Cruz
Country	Argentina
Extent	Golfo San Jorge Basin
Type section
Named by	Teruggi & Rossetto
Year defined	1963
Bajo Barreal Formation (Argentina)

Vertebrate paleofauna

Dinosaurs

Dinosaur remains are among the fossils that have been recovered from the formation.[4] Dinosaur remains include the abelisaurid theropod Xenotarsosaurus bonapartei, as well as indeterminate teeth belonging to carcharodontosaurids and dromaeosaurids.[5]

Dinosaurs reported from the Bajo Barreal Formation
Genus	Species	Stratigraphic position	Material	Notes	Images
Aniksosaurus[6]	A. darwini[6]	Lower		A basal coelurosaur
Campylodoniscus[6][7]	C. ameghinoi[6]	Lower	Maxilla with seven teeth.[8]
Clasmodosaurus[8]	C. spatula[6]		Jaw with seven teeth[8]	A sauropod
Drusilasaura[9]	D. deseadensis	Upper	"four dorsal vertebrae, one sacral vertebra, six caudal vertebrae, left scapula, dorsal rib fragments, two haemapophyses and indeterminate fragments"	A titanosaur belonging to Lognkosauria
Epachthosaurus[6]	E. sciuttoi[6]	Lower	"Vertebrae [and] partial illium."[10]
Notohypsilophodon[6]	N. comodorensis[6]	Lower	"Vertebrae, partial fore- and hindlimb"[11]
Sarmientosaurus[12]	S. musacchioi	Lower	A skull	A lithostrotian titanosaur
Xenotarsosaurus[6]	X. bonapartei[6]	Lower	A vertebra and a nearly complete hind limb[13]

Other fossils

Other fossils found in the formation include:[14][15][16]

• Bonapartemys bajobarrealis
• Katepensaurus goicoecheai
• Prochelidella argentinae
• Andesaurus sp.
• Megaraptor sp.
• Abelisauridae indet.
• Anura indet.
• Carcharodontosauridae indet.
• Chelonia indet.
• Crocodylia indet.
• Dromaeosauridae indet.
• Pterosauria indet.
• Rebbachisauridae indet.

See also

• List of dinosaur-bearing rock formations
• Mata Amarilla Formation, contemporaneous formation of the Austral Basin
• Lisandro Formation, contemporaneous formation of the Neuquén Basin

References

1. Casal et al., 2016, p.55
2. Bajo Barreal Formation at Fossilworks.org
3. Sywan, 2001, p.131
4. Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 600-604. ISBN 0-520-24209-2.
5. Casal, G., Candeiro, C.R.A., Martínez, R., Ivany, E., and Ibiricu, L. (2009). "Dientes de Theropoda (Dinosauria: Saurischia) de la Formación Bajo Barreal, Cretácico Superior, Provincia del Chubut, Argentina." Geobios, doi:10.1016/j.geobios.2009.03.002.
6. "63.2 Provincia de Chubut, Argentina; 2. Bajo Barreal Formation," in Weishampel, et al. (2004). Page 602.
7. Haubold, H. & Kuhn, O., 1961, Lebensbilder und Evolution fossiler Saurier, Amphibien und Reptilien, Wittenberg : Ziemsen
8. Huene, F. von, 1929, "Los Saurisquios y Ornitisquios del Cretaceo Argentino", Anales del Museo de La Plata, 3(2): 82-83
9. César Navarrete, Gabriel Casal and Rubén Martínez (2011). "Drusilasaura deseadensis gen. et sp. nov., a new titanosaur (Dinosauria-Sauropoda), of the Bajo Barreal Formation, Upper Cretaceous of north of Santa Cruz, Argentina". Revista Brasileira de Paleontologia 14 (1): 1-14. doi:10.4072/rbp.2011.1.01.
10. "Table 13.1," in Weishampel, et al. (2004). Page 268.
11. "Table 18.1," in Weishampel, et al. (2004). Page 395.
12. Martínez et al., 2016
13. "Table 3.1," in Weishampel, et al. (2004). Page 49.
14. Casal, 2016, p.58
15. Estancia Laguna Palacios "2005 Quarry" at Fossilworks.org
16. 6 km north of Estancia "Ocho Hermanos" at Fossilworks.org

Bibliography

• Casal, Gabriel A.; Ruben D. Martínez; Marcelo Luna, and Lucio M. Ibiricu. 2016. Ordenamiento y caracterización faunística del Cretácico Superior del Grupo Chubut, Cuenca del Golfo San Jorge, Argentina. Revista Brasileira de Paleontologia 19. 53–70. Accessed 2019-02-16.
• Martínez, Rubén D.F.; Matthew C. Lamanna; Fernando E. Novas; Ryan C. Ridgely; Gabriel A. Casal; Javier E. Martínez; Javier R. Vita, and Lawrence M. Witmer. 2016. A Basal Lithostrotian Titanosaur (Dinosauria: Sauropoda) with a Complete Skull: Implications for the Evolution and Paleobiology of Titanosauria. PLoS ONE 11. e0151661. Accessed 2019-02-16.
• Sylwan, Claudio A. 2001. Geology of the Golfo San Jorge Basin, Argentina. Journal of Iberian Geology 27. 123–157. Accessed 2018-09-04.
• 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

Further reading

• G. Casal and L. Ibiricu. 2010. Materiales asignables a Epachthosaurus Powell, 1990 (Sauropoda: Titanosauria), de la Formación Bajo Barreal, Cretácico Superior, Chubut, Argentina [Materials assignable to Epachthosaurus Powell, 1990 (Sauropoda: Titanosauria), from the Bajo Barreal Formation, Upper Cretaceous, Chubut, Argentina]. Revista Brasileira de Paleontologia 13(3):247-256
• L. M. Ibiricu, G. A. Casal, R. D. Martinez, M. C. Lamanna, M. Luna and L. Salgado. 2013. Katepensaurus goicoecheai, gen. et sp. nov., a Late Cretaceous rebbachisaurid (Sauropoda, Diplodocoidea) from central Patagonia, Argentina. Journal of Vertebrate Paleontology 33(6):1351-1366
• L. M. Ibiricu, G. A. Casal, M. C. Lamanna, R. D. Martínez, J. D. Harris and K. J. Lacovara. 2012. The southernmost records of Rebbachisauridae (Sauropoda: Diplodocoidea), from early Late Cretaceous deposits in central Patagonia. Cretaceous Research 34:220-232
• R. D. Martínez, F. E. Novas, and A. Ambrosio. 2004. Abelisaurid remains (Theropoda, Ceratosauria) from southern Patagonia. Actas I del Congreso Ltinoamericano de Paleontología de Vertebrados. Ameghiniana 41(4):577-585
• R. D. Martínez and F. E. Novas. 1997. Un nuevo tetanuro (Dinosauria: Theropoda) de la Formación Bajo Barreal (Cretácico Superior), Patagonia [A new tetanuran (Dinosauria: Theropoda) from the Bajo Barreal Formation (Upper Cretaceous), Patagonia]. Ameghiniana 34(4):538
• R. D. Martínez, A. Maure, M. Oliva and M. Luna. 1993. Un maxilar de Theropoda (Abelisauria) de la Formación Bajo Barreal, Cretacico Tardio, Chubut, Argentina [A theropod (Abelisauria) maxilla from the Bajo Barreal Formation, Late Cretaceous, Chubut, Argentina]. Ameghiniana 30(1):109-110
• J. C. Sciutto and R. D. Martínez. 1994. Un nuevo yacimiento fosilífero de la Formación Bajo Barreal (Cretacico Tardio) y su fauna de saurópodos [A new fossiliferous locality in the Bajo Barreal Formation (Late Cretaceous) and its sauropod fauna]. Naturalia Patagonica, Ciencias de la Tierra 2:27-47