Chota Formation

Chota Formation
Stratigraphic range: Early Campanian-Late Eocene ~83–35 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Esperanza Mb. Rentema Mb. Fundo El Triunfo Mb.
Underlies	Cajaruro Formation
Overlies	Celendín Formation
Thickness	320 m (1,050 ft)
Lithology
Primary	Shale, sandstone
Other	Gypsum
Location
Coordinates	5°41′41″S 78°30′41″W / 5.69472°S 78.51139°W / -5.69472; -78.51139
Approximate paleocoordinates	7°30′S 60°36′W / 7.5°S 60.6°W / -7.5; -60.6
Region	Cajamarca
Country	Peru
Extent	Bagua Basin
Type section
Named for	Chota
Named by	Broggi
Location	Esperanza, Cajamarca
Year defined	1942
Chota Formation (Peru)

The Chota Formation is an Early Campanian to Late Eocene geologic formation of the Cajamarca and western Amazonas Region in northern Peru. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus ("Baguasaurus").^[1] The formation was formerly named Bagua Formation.^[2]

Fossil content

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

Dinosaurs

Sauropods

Sauropods of the Chota Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Lithostrotia indet.	Indeterminate	Cajamarca	Campanian to Maastrichtian		A Lithostrotian titanosaur; informally known as "Baguasaurus".

Crocodylomorphs

Crocodylomorph of the Chota Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Crocodylomorpha indet.[3]	Indeterminate	Cajamarca	Campanian to Maastrichtian	Teeth	Possibly a Notosuchia; previously known as Spinosauridae.[4]

Fish

Fishes of the Chota Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Pucabatis	P. hoffstetteri	Cajamarca	Maastrichtian		A rhombodontid rajiform

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with indeterminate dinosaur fossils

References

1. Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
2. Chacaltana et al., 2014
3. Barker, Chris T.; Naish, D.; Gostling, Neil J. (2025). "Insufficient Evidence for Spinosaurid Survival into the Latest Cretaceous: A Comment on Olmedo-Romaña et al. (2025)". Ameghiniana. doi:10.5710/AMGH.10.12.2025.3673.
4. Olmedo-Romaña, G. J.; Wilson Mantilla, J. A.; Tejada, J. V.; Antoine, P. O.; Burga-Castillo, M. A.; Aliaga-Castillo, A. V.; Varas-Malca, R.; Benites-Palomino, A.; Salas-Gismondi, R. (2025). "Theropod and sauropod dinosaurs from the Campanian-Maastrichtian Bagua Basin of Perú, including the first possible report of Spinosauridae in western South America". Ameghiniana. 62 (4): 259–287. doi:10.5710/AMGH.13.02.2025.3627.

Bibliography

• Chacaltana, César; Benites Cañote, Alexandra Lucytania; Valdivia, Waldir; Chumpitaz, Marco (2014), La formación Chota en la Cuenca Bagua: Evaluación e implicancias del criterio de clasificación litoestratigráfico, Congreso Peruano de Geología, pp. 1–4, retrieved 2017-06-05
• Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), The Dinosauria, 2nd edition, Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2, retrieved 2019-02-21

Further reading

• Aliaga Chávez, Manuel Jesús, Estudio geológico (PDF), UNMSM, pp. 1–22, retrieved 2017-06-05
• Cruzado Vásquez, Gilberto (2009), Estudio de geología (PDF), Gobierno regional de Cajamarca, pp. 1–90, retrieved 2017-06-05
• T. Mourier, P. Bengtson, M. Bonhomme, E. Buge, H. Cappetta, J.-Y. Crochet, M. Feist, K. F. Hirsch, E. Jaillard, G. Laubacher, J. P. Lefranc, M. Moullade, C. Noblet, D. Pons, J. Rey, B. Sigé, Y. Tambareau and P. Taquet. 1988. The Upper Cretaceous–Lower Tertiary marine to continental transition in the Bagua Basin, northern Peru: paleontology, biostratigraphy, radiometry, correlations. Newsletters on Stratigraphy 19(3):143-177