El Gallo Formation

El Gallo Formation
Stratigraphic range:
Santonian–Maastrichtian
Afloramiento de la formación El Gallo
TypeGeological formation
Sub-unitsEl Disecado Member
Thicknessup to ca. 1,150 m (3,770 ft) (El Disecado Member)
Lithology
PrimaryMudstone, sandstone
OtherSiltstone
Location
Coordinates30°06′N 115°48′W / 30.1°N 115.8°W / 30.1; -115.8
Approximate paleocoordinates35°30′N 85°48′W / 35.5°N 85.8°W / 35.5; -85.8
RegionBaja California
CountryMexico
El Gallo Formation is located in Mexico
El Gallo Formation
El Gallo Formation (Mexico)
Paleogeography of the Campanian, showcasing what North America was like during the time range the formation spans

The El Gallo Formation is a geological formation in Mexico whose strata date back to the Late Cretaceous, from the Santonian to the Maastrichtian. Dinosaur remains are among the fossils that have been recovered from the formation.

Vertebrate paleofauna

Crurotarsans

Crurotarsans of the El Gallo Formation
GenusSpeciesLocationMemberAbundanceNotesImages
Brachychampsa
Leidyosuchus

Dinosaurs

Indeterminate theropod, coelurosaur, dromaeosaurid, tyrannosaurid, hadrosaurid, and ankylosaurid remains are known from the formation. Dinosaur eggs are known from the formation. Alexornis antecedens actually comes from the La Bocana Roja Formation. An indeterminate hadrosaurine is known from the formation. Potential Hypacrosaurus remains have been unearthed here.

Dinosaurs of the El Gallo Formation
GenusSpeciesLocationMemberAbundanceNotesImages
cf. Chirostenotes C. sp.
Gryposaurus Indeterminate
Lambeosaurus L. laticaudus
Magnapaulia M. laticaudus El Rosario site El Disecado A partial skeleton A large lambeosaur
Saurornitholestinae Indeterminate
cf. Troodon T. formosus
Tyrannosauridae Indeterminate Possibly represents a new taxon.
Maniraptora Maniraptora indet.
Troodontidae Troodontidae indet.
Dromaeosauridae Dromaeosauridae indet.
Theropoda Theropoda indet.

Lepidosaurs

The diversity of lepidosaurs in El Gallo formation is scarce. However, the Polyglyphanodontian Dicothon bajaensis is by far the lizard with an important fossil record for this formation .

Lepidosaurs of the El Gallo Formation
GenusSpeciesLocationMemberAbundanceNotesImages
Dicothodon bajaensis
Paraglyphanodon Indeterminate Probably a juvenile Polyglyphanodon.

Mammals

Mammals of the El Gallo Formation
GenusSpeciesLocationStratigraphic positionAbundanceNotesImages
Cimolodon C. desosai
Mesodma M. formosa
Pediomys Indeterminate
Stygimys Indeterminate

Amphibians

An indeterminate albanerpetontid is known from the formation.

See also

References

  1. ↑ Kane, I. A.; Hodgson, D. M.; Hubbard, S. M.; McArthur, A. D.; Poyatos-Moré, M.; Soutter, E. L.; Flint, S. S.; Matthews, W. (2022). "Deep-water Tectono-Stratigraphy at a Plate Boundary Constrained by Large N-Detrital Zircon and Micropaleontological Approaches: Peninsular Ranges Forearc, Baja California, Mexico". The Sedimentary Record. 20 (1). doi:10.2110/001c.37652. S2CID 59406495.
  2. ↑ "El Gallo Formation." Weishampel et al., 2004, pp.587-588
  3. ↑ "Appendix: Summary of the Mesozoic Reptilian Fossils of California," in Hilton (2003) p. 277
  4. 1 2 3 4 5 Ramírez-Velasco, A. A.; Hernández-Rivera, R. (2015). "Diversity of late cretaceous dinosaurs from Mexico" (PDF). Boletín Geológico y Minero. 126 (1): 63–108. Archived from the original (PDF) on 2022-02-25. Retrieved 2020-10-02.
  5. 1 2 3 4 "El Gallo Formation, Baja California Del Norte, Mexico," in Sullivan and Lucas (2006). Page 16.
  6. 1 2 Cabrera Hernandez, Jonathan S.; Hernandez Rivera, René; Montellano, Marisol (2018). "FOSSIL EGGSHELLS AND TWO PERINATAL DINOSAURS FROM THE EL GALLO FORMATION (LATE CRETACEOUS), EL ROSARIO, BAJA CALIFORNIA, MEXICO". Journal of Vertebrate Paleontology, Program and Abstracts. 38. Archived from the original on 2018-10-22. Retrieved 2020-10-14.
  7. ↑ Morris, William J. (1967). "Baja California: Late Cretaceous Dinosaurs". Science. 155 (3769): 1539–1541. ISSN 0036-8075.
  8. ↑ Morris, William J. (1973). "A Review of Pacific Coast Hadrosaurs". Journal of Paleontology. 47 (3): 551–561. ISSN 0022-3360.
  9. 1 2 "Appendix: Summary of the Mesozoic Reptilian Fossils of California," in Hilton (2003) p. 260
  10. 1 2 "4.5 Estado de Baja California Norte, Mexico; 1. El Gallo Formation," in Weishampel, et al. (2004). Pages 587-588.
  11. 1 2 3 4 García-Gil, Vanessa Alexandra; Torices, Angélica; López-Miguel, Mirella; Montellano-Ballesteros, Marisol (2026). "Isolated teeth of small theropods from the El Gallo Formation, Baja California, Mexico". Cretaceous Research. 181 106292. doi:10.1016/j.cretres.2025.106292.
  12. ↑ México, Dirección General de Repositorios Universitarios, Universidad Nacional Autónoma de. "Repositorio Institucional de la Universidad Nacional Autónoma de México". repositorio.unam.mx (in Mexican Spanish). Retrieved 2026-04-01.{{cite web}}: CS1 maint: multiple names: authors list (link)
  13. ↑ Chavarría-Arellano, María Luisa; Simões, Tiago R.; Montellano-Ballesteros, Marisol (2018). "New data on the Late Cretaceous lizard Dicothodon bajaensis (Squamata, Borioteiioidea) from Baja California, Mexico reveals an unusual tooth replacement pattern in squamates". Anais da Academia Brasileira de Ciências. 90: 2781–2795. doi:10.1590/0001-3765201820170563. ISSN 0001-3765.
  14. 1 2 3 4 Listed as "cf. Paraglyphanodon" in "El Gallo Formation, Baja California Del Norte, Mexico," in Sullivan and Lucas (2006). Page 16.
  15. ↑ Wilson Mantilla, G. P.; Newbins, I. R.; Fastovsky, D. E.; Zhang, Y.; Montellano-Ballesteros, M.; García Alcántara, D.; Chen, M. (2026). "Cranial and postcranial remains of a new species of Cimolodon (Mammalia, Multituberculata, Cimolodontidae) from the Upper Cretaceous (Campanian) El Gallo Formation of Baja California, México". Journal of Vertebrate Paleontology e2641109. doi:10.1080/02724634.2026.2641109.
  16. 1 2 Listed as "Mesodma cf. M. formosa" in "El Gallo Formation, Baja California Del Norte, Mexico," in Sullivan and Lucas (2006). Page 16.
  17. ↑ Romo de Vivar Martínez, Paulo R.; Montellano Ballesteros, Marisol; García Alcántara, Dalia; Romo de Vivar Martínez, Paulo R.; Montellano Ballesteros, Marisol; García Alcántara, Dalia (December 2016). "Primer registro de la Familia Albanerpetontidae (Lissamphibia) en la formación El Gallo (Campaniano, Cretácico Superior), Baja California, México". Boletín de la Sociedad Geológica Mexicana (in Spanish). 68 (3): 571–580. doi:10.18268/BSGM2016v68n3a11. ISSN 1405-3322.

Bibliography

Further reading