El Gallo Formation

The El Gallo Formation is a geological formation in Mexico whose strata date back to the Late Cretaceous, from the Santonian to the Maastrichtian.^[1] Dinosaur remains are among the fossils that have been recovered from the formation.^[2]

El Gallo Formation
Stratigraphic range: Santonian–Maastrichtian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	El Disecado Member
Thickness	up to ca. 1,150 m (3,770 ft) (El Disecado Member)
Lithology
Primary	Mudstone, sandstone
Other	Siltstone
Location
Coordinates	30.1°N 115.8°W / 30.1; -115.8
Approximate paleocoordinates	35.5°N 85.8°W / 35.5; -85.8
Region	Baja California
Country	Mexico
El Gallo Formation (Mexico)

Paleogeography of the Campanian, showcasing what North America was like during the time range the formation spans

Vertebrate paleofauna

Crurotarsans

Crurotarsans of the El Gallo Formation
Genus	Species	Location	Member	Abundance	Notes	Images
Brachychampsa	[3]
Leidyosuchus

Dinosaurs

Indeterminate theropod, coelurosaur, dromaeosaurid, tyrannosaurid, hadrosaurid, and ankylosaurid remains are known from the formation.^[4] Dinosaur eggs are known from the formation.^[5] Alexornis antecedens actually comes from the La Bocana Roja Formation. An indeterminate hadrosaurine is known from the formation.^[6] Potential Hypacrosaurus remains have been unearthed here.^[7][8]

Dinosaurs of the El Gallo Formation
Genus	Species	Location	Member	Abundance	Notes	Images
cf. Chirostenotes[4]	C. sp.
Gryposaurus[6]	Indeterminate
Lambeosaurus[9]	L. laticaudus[9]
Magnapaulia	M. laticaudus
Saurornitholestinae[4]	Indeterminate
cf. Troodon[10]	T. formosus[10]
Tyrannosauridae[4]	Indeterminate				Possibly represents a new taxon.[4]

Lepidosaurs

Lepidosaurs of the El Gallo Formation
Genus	Species	Location	Member	Abundance	Notes	Images
Paraglyphanodon[11]	Indeterminate[11]				Probably a juvenile Polyglyphanodon.[5]
Polyglyphanodon[5]	P. bajaensis[5]

Mammals

Mammals of the El Gallo Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes	Images
Mesodma[12]	M. formosa[12]
Pediomys[5]	Indeterminate[5]
Stygimys[11]	Indeterminate[11]

Amphibians

An indeterminate albanerpetontid is known from the formation.^[13]

See also

• List of dinosaur-bearing rock formations
• List of fossiliferous stratigraphic units in Mexico