Río Colorado Subgroup
Geologic subgroup in Argentina
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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]
Allen Formation
| Río Colorado Subgroup | |
|---|---|
| Stratigraphic range: Santonian-Early Campanian ~ | |
| 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 |
| Approximate paleocoordinates | 40.8°S 53.0°W |
| Region | Neuquén & Río Negro Provinces |
| Country | Argentina |
| Extent | Neuquén Basin |
  Río Colorado Subgroup (Argentina) | |
Fossil content
Ornithischians
| Ornithischians reported from the Río Colorado Subgroup | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Province | Stratigraphic position | Material | Notes | Images |
|
G. cincosaltensis[3] |
Anacleto Formation |
"Skull and postcranial skeleton, postcranial elements, juvenile to subadult."[4] |
 | |||
Sauropods
Titanosaur eggs are known from Neuquén Province.[5]
| Sauropods reported from the Río Colorado Subgroup | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Province | Stratigraphic position | Material | Notes | Images |
|
A. wichmannianus[3] |
Anacleto Formation |
   | ||||
|
B.reigi[3] |
Allen Formation | |||||
|
L. scutatus[6] |
||||||
|
M. patagonicus[5] |
Bajo de la Carpa Formation |
Possible synonym of Neuquensaurus | ||||
|
N. australis[7] |
Anacleto Formation | |||||
|
"T." robustus[3] |
Anacleto Formation | |||||
|
T. nanus[7] |
Bajo de la Carpa Formation | |||||
Theropods
| Theropods reported from the Río Colorado Subgroup | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Province | Stratigraphic position | Material | Notes | Images |
|
A. comahuaensis[3] |
Anacleto Formation |
"Partial skull."[8] |
     | |||
|
A. calvoi[5] |
Bajo de la Carpa Formation |
"Partial postcranial skeleton."[9] |
||||
|
A. garridoi[5] |
Anacleto Formation |
"Nearly complete skeleton."[8] |
||||
|
N. volans[5] |
Bajo de la Carpa Formation |
"Partial skeleton."[10] |
||||
|
P. deferrariisi[5] |
Bajo de la Carpa Formation |
"Many skeletons."[11] |
||||
|
V. unicus[5] |
Bajo de la Carpa Formation |
"Partial hind limb."[8] |
||||