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.[1]

Candeleros Formation
Stratigraphic range: early Cenomanian
~99–97 Ma
Candeleros Formation near Cerro El Vagon, Neuquen, Argentina
TypeGeological formation
Unit ofNeuquén Group
 Río Limay Subgroup
UnderliesHuincul Formation
OverliesLohan Cura Formation
Thickness300 m (980 ft)
Lithology
PrimaryEolian sandstone
OtherConglomerate, siltstone, paleosol
Location
Coordinates39°24′S 69°12′W / 39.4°S 69.2°W / -39.4; -69.2
Approximate paleocoordinates46°30′S 45°30′W / 46.5°S 45.5°W / -46.5; -45.5
RegionMendoza, Neuquén & Río Negro Provinces
CountryArgentina
ExtentNeuquén Basin
Type section
Named forCandeleros Hill
Named byWichmann
Year defined1929
Candeleros Formation is located in Argentina
Candeleros Formation
Candeleros Formation (Argentina)

Description

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The type locality of the Candeleros Formation is Candeleros Hill in Neuquén Province, after which the formation was named by Wichmann in 1929.[2] 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.[3]

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.[1][3]

Fossil content

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Life restoration of dinosaurs in Candeleros Formation

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.[4]

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

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

Amphibians

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Taxa Species Locality Member Material Notes Images
Avitabatrachus[5] A. uliana El Gigante Lower Fragmentary skull and postcranial skeleton A pipimorph frog

Dinosaurs

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Ornithischians

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Taxa Species Locality Member Material Notes Images
Bonaparteichnium[6] B. tali Footprints Iguanodont ichnofossils
Jakapil[7] J. kaniukura Cerro Policía Upper A partial skeleton including several osteoderms and a complete lower jaw Possibly a basal thyreophoran[8]  

Saurischians

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Sauropods
Taxa Species Locality Member Material Notes Images
Andesaurus A. delgadoi Lower A partial skeleton A basal titanosaur
 
Campananeyen[9] 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; possibly Argentinosaurus
Theropods
Taxa Species Locality Member Material Notes Images
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

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Taxa Species Locality Member Material Notes Images
Azhdarchidae[10] Indeterminate Ezequiel Ramos Mexía Reservoir Upper A partial cervical vertebra An azhdarchid

Other reptiles

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Taxa Species Locality Member Material Notes Images
Araripesuchus A. buitreraensis La Buitrera, Cerro Policía and El Pueblito. Upper Multiple skull specimens. A small notosuchian crocodyliform  
A manzanensis Upper A partial skull and lower jaw
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
Najash N. rionegrina Upper A basal snake  
Priosphenodon P. avelasi Upper An eilenodontine rhynchocephalian
 
Tika T. giacchinoi Upper A sphenodontine rhynchocephalian

Mammals

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

Turtles

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Taxa Species Locality Member Material Notes Images
Prochelidella[11] P. buitreraensis Upper A small chelid turtle
Elkanemys[12] E. pritchardi Upper A bothremydid turtle

See also

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References

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  1. ^ a b Sánchez et al., 2006
  2. ^ Wichmann, 1929
  3. ^ a b Leanza et al., 2004
  4. ^ Leonardi, 1994, p. 79
  5. ^ Baez, Ana & Trueb, Linda & Calvo, Jorge. (2000). The earliest known pipoid frog from South America: A new genus from the Middle Cretaceous of Argentina. Journal of Vertebrate Paleontology. 20. 490-500. 10.1671/0272-4634(2000)020%5B0490:TEKPFF%5D2.0.CO;2.
  6. ^ Calvo, Jorge O. (1991). "Huellas de dinosaurios en la Formación Río Limay (Albiano-Cenomaniano?), Picún Leufú, Provincia del Neuquén, República Argentina (Ornithischia-Saurischia: Sauropoda-Theropoda)". Ameghiniana. 28 (3): 241–258.
  7. ^ Riguetti FJ, Apesteguía S, Pereda-Suberbiola X (2022). "A new Cretaceous thyreophoran from Patagonia supports a South American lineage of armoured dinosaurs". Scientific Reports. 12 (1): Article number 11621. Bibcode:2022NatSR..1211621R. doi:10.1038/s41598-022-15535-6. PMC 9372066. PMID 35953515.
  8. ^ Raven, T. J.; Barrett, P. M.; Joyce, C. B.; Maidment, S. C. R. (2023). "The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora)" (PDF). Journal of Systematic Palaeontology. 21 (1). 2205433. Bibcode:2023JSPal..2105433R. doi:10.1080/14772019.2023.2205433.
  9. ^ Lerzo, Lucas N.; Fernández-Baldor, Fidel Torcida; Canale, Juan I.; Whitlock, John A.; Otero, Alejandro; Gallina, Pablo A. (2024-08-13). "They all floated in the Cretaceous: new rebbachisaurid (Sauropoda, Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina". Historical Biology: 1–14. doi:10.1080/08912963.2024.2383708. ISSN 0891-2963.
  10. ^ Agnolin, Federico; Rozadilla, Sebastián; Juárez-Valieri, Rubén; Meso, Jorge (2023-10-25). "Oldest azhdarchid (Pterosauria) record from South America". Revista del Museo Argentino de Ciencias Naturales. Nueva serie (in Spanish). 25 (2): 309–314. ISSN 1853-0400.
  11. ^ Maniel, Ignacio J.; de la Fuente, Marcelo S.; Apesteguía, Sebastián; Pérez Mayoral, Joaquin; Sanchez, Maria L.; Veiga, Gonzalo D.; Smales, Ian (2020-02-24). "Cranial and postcranial remains of a new species of Prochelidella (Testudines: Pleurodira: Chelidae) from 'La Buitrera' (Cenomanian of Patagonia, Argentina), with comments on the monophyly of this extinct chelid genus from southern Gondwana". Journal of Systematic Palaeontology. 18 (12): 1033–1055. Bibcode:2020JSPal..18.1033M. doi:10.1080/14772019.2020.1721579. S2CID 214500365. Retrieved 2020-07-11.
  12. ^ Maniel, I.J.; de la Fuente, M. S.; Zhuo, J.I. (2021). "The first Cearachelyini (Pelomedusoides, Bothremydidae) turtle from the Upper Cretaceous of Patagonia, and an overview of the occurrence and diversity of Pelomedusoides in Patagonia". Cretaceous Research. 125: Article 104869. Bibcode:2021CrRes.12504869M. doi:10.1016/j.cretres.2021.104869.

Bibliography

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