Río Colorado Subgroup

Not to be confused with Colorado Formation.

The Río Colorado Subgroup, formerly named as Río Colorado Formation, is a Late Cretaceous (Santonian to Early Campanian) geologic subgroup of the Neuquén Basin in northern Patagonia, Argentina. It belongs to the Neuquén Group and contains the Anacleto and Bajo de la Carpa Formations. The subgroup overlies the Río Neuquén Subgroup and is overlain by the Allen Formation of the Malargüe Group, separated by an unconformity dated to 79 Ma.^[1] Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.^[2]

Río Colorado Subgroup
Stratigraphic range: Santonian-Early Campanian ~86–79 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Subgroup
Unit of	Neuquén Group
Sub-units	Anacleto & Bajo de la Carpa Formations
Underlies	Malargüe Group  Allen Formation
Overlies	Río Neuquén Subgroup  Plottier Formation
Thickness	Up to 240 m (790 ft)
Lithology
Primary	Mudstone, sandstone
Other	Siltstone, limestone
Location
Coordinates	37.9°S 68.5°W / -37.9; -68.5
Approximate paleocoordinates	40.8°S 53.0°W / -40.8; -53.0
Region	Neuquén & Río Negro Provinces
Country	Argentina
Extent	Neuquén Basin
Río Colorado Subgroup (Argentina)

Fossil content

See also: Anacleto Formation § Fossil content, and Bajo de la Carpa Formation § Fossil content

Ornithischians

Ornithischians reported from the Río Colorado Subgroup
Genus	Species	Province	Stratigraphic position	Material	Notes	Images
Gasparinisaura[3]	G. cincosaltensis[3]	Río Negro Province[3]	Anacleto Formation	"Skull and postcranial skeleton, postcranial elements, juvenile to subadult."[4]		Gasparinisaura

Sauropods

Titanosaur eggs are known from Neuquén Province.^[5]

Sauropods reported from the Río Colorado Subgroup
Genus	Species	Province	Stratigraphic position	Material	Notes	Images
Antarctosaurus[3]	A. wichmannianus[3]	Río Negro Province[3]	Anacleto Formation			Antarctosaurus
Bonatitan[3]	B.reigi[3]	Río Negro Province[3]	Allen Formation
Loricosaurus[6]	L. scutatus[6]	Neuquén Province[5] Río Negro Province[3]
Microcoelus[5]	M. patagonicus[5]	Neuquén Province[5]	Bajo de la Carpa Formation		Possible synonym of Neuquensaurus
Neuquensaurus[7]	N. australis[7]	Neuquén Province[5] Río Negro Province[3]	Anacleto Formation
"Titanosaurus"[3]	"T." robustus[3]	Río Negro Province[3]	Anacleto Formation
Titanosaurus[7]	T. nanus[7]	Neuquén Province[5]	Bajo de la Carpa Formation

Theropods

Theropods reported from the Río Colorado Subgroup
Genus	Species	Province	Stratigraphic position	Material	Notes	Images
Abelisaurus[3]	A. comahuaensis[3]	Río Negro Province[3]	Anacleto Formation	"Partial skull."[8]		Abelisaurus Alvarezsaurus Aucasaurus Patagopteryx Velocisaurus
Alvarezsaurus[5]	A. calvoi[5]	Neuquén Province[5]	Bajo de la Carpa Formation	"Partial postcranial skeleton."[9]
Aucasaurus[5]	A. garridoi[5]	Neuquén Province[5]	Anacleto Formation	"Nearly complete skeleton."[8]
Neuquenornis[5]	N. volans[5]	Neuquén Province[5]	Bajo de la Carpa Formation	"Partial skeleton."[10]
Patagopteryx[5]	P. deferrariisi[5]	Neuquén Province[5]	Bajo de la Carpa Formation	"Many skeletons."[11]
Velocisaurus[5]	V. unicus[5]	Neuquén Province[5]	Bajo de la Carpa Formation	"Partial hind limb."[8]

See also

• List of stratigraphic units with dinosaur body fossils
• List of stratigraphic units with dinosaur trace fossils