# Candeleros Formation

The Candeleros Formation is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup. Formerly that subgroup was treated as a formation, and the Candeleros Formation was known as the Candeleros Member.

## Description

The type locality of the Candeleros Formation is Candeleros Hill in Neuquén Province, after which the formation was named by Wichmann in 1929. This formation unconformably overlies the Lohan Cura Formation, and it is fused with the Huincul Formation, also a unit of the Neuquén Group. The sediments of the latter are of lighter greenish and yellow colors and the fused boundary between the Candeleros and Huincul formations is easily recognizable.
The Candeleros Formation is almost 300 metres (980 ft) thick in some sections. Overall, the formation represents a part of the ancient Kokorkom desert with braided river system, made up mostly of sandstones and conglomerates. There are also isolated sections that represent eolian (wind-blown) deposition, as well as siltstones deposited under swamp conditions. Paleosols (soil deposits) are common in some sections as well.

## Fossil content

The Candeleros Formation has a very diverse fossil fauna, including fish, frogs, mammals, rhynchocephalians, snakes, turtles, notosuchians, pterosaurs, and abundant dinosaurs including rebbachisaurid and titanosaurian sauropods and diverse theropods, and the enigmatic armored Jakapil.
Ichnofossils found in the formation include those assigned to Sousaichnum monettae, Limayichnus major, Bressaniichnus patagonicus, Deferraiichnum mapuchense, and Picunichnus benedettoi.
| 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. |

### Fish

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Ceratodus | C. argentinus | | Upper | | A lungfish | |

### Amphibians

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Avitabatrachus | A. uliana | El Gigante | Lower | Fragmentary skull and postcranial skeleton | A pipimorph frog | |

### Dinosaurs
#### Ornithischians

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Bonaparteichnium | B. tali | | | Footprints | Iguanodont ichnofossils | |
| Jakapil | J. kaniukura | Cerro Policía | Upper | A partial skeleton including several osteoderms and a complete lower jaw | Possibly a basal thyreophoran | |

#### Saurischians
##### Sauropods

| Taxa | Species | Locality | Member | Material | Notes |
| Andesaurus | A. delgadoi | | Lower | A partial skeleton | A basal titanosaur |
| Campananeyen | C. fragilissimus | Barda Atravesada de Las Campanas | Lower | A fragmentary skeleton | A rebbachisaurid |
| Limaysaurus | L. tessonei | | Upper | | A rebbachisaurid |
| Nopcsaspondylus | N. alarconensis | | | | A rebbachisaurid |
| Rayososaurus | R. agrioensis | Agrio del Medio | Upper | A left scapula, an almost complete right scapular blade, and the distal three-quarters of a left femur. | A rebbachisaurid |
| Titanosauria | Indeterminate | | Upper | | A giant titanosaur, probably exceeding Patagotitan in size |

##### Theropods

| Taxa | Species | Locality | Member | Material | Notes |
| Abelichnus | A. astigerrae | | | A footprint | |
| Alnashetri | A. cerropoliciensis | La Buitrera | Upper | A fragmentary skeleton including leg and foot bones | An alvarezsauroid |
| Bicentenaria | B. argentina | Ezequiel Ramos Mexia Reservoir | Upper | Much of a skeleton | A coelurosaur |
| Buitreraptor | B. gonzalezorum | La Buitrera | Upper | Several partial skeletons | A dromaeosaurid |
| Ekrixinatosaurus | E. novasi | Bajo del Añelo | Upper | A partial skeleton | An abelisaurid |
| Giganotosaurus | G. carolinii | Los Candeleros and Villa El Chocón | Upper/Lower | A partial skull and a disarticulated postcranial skeleton | A carcharodontosaurid |

### Pterosaurs

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Azhdarchidae | Indeterminate | Ezequiel Ramos Mexía Reservoir | Upper | A partial cervical vertebra | An azhdarchid | |

### Other reptiles

| Taxa | Species | Locality | Member | Material | Notes |
| Araripesuchus | A. buitreraensis | La Buitrera, Cerro Policía and El Pueblito. | Upper | Multiple skull specimens. | A small notosuchian crocodyliform |
| Araripesuchus | A manzanensis | | Upper | A partial skull and lower jaw | A small notosuchian crocodyliform |
| Araripesuchus | A. patagonicus | El Chocón. | Lower | An anterior half of the skull with an articulated mandible, lacking the most anterior portion of the rostrum and also preserves part of the postcranium | A small notosuchian crocodyliform |
| Najash | N. rionegrina | | Upper | | A basal snake |
| Priosphenodon | P. avelasi | | Upper | | An eilenodontine rhynchocephalian |
| Tika | T. giacchinoi | | Upper | | A sphenodontine rhynchocephalian |

### Mammals

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Cronopio | C. dentiacutus | La Buitrera | Upper | Skull bones and teeth | A small meridiolestidan mammal | |

### Turtles

| Taxa | Species | Locality | Member | Material | Notes | Images |
| Prochelidella | P. buitreraensis | | Upper | | A small chelid turtle | |
| Elkanemys | E. pritchardi | | Upper | | A bothremydid turtle | |