La Colonia Formation

Coordinates: 43°00′S 67°30′W / 43.0°S 67.5°W / -43.0; -67.5
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La Colonia Formation
Stratigraphic range: Campanian-Maastrichtian
~73–66 Ma
An outcrop of the La Colonia Formation on the Somún Curá plateau that is the type locality of Chubutinectes. Photographed in 2009.
TypeGeological formation
Sub-unitsLower, Middle and Upper members
UnderliesEl Buitre & Sarmiento Formations
OverliesCerro Barcino & Paso del Sapo Formations
ThicknessUp to 210–240 m (690–790 ft)
Thinning to 17 m (56 ft) around Telsen
Lithology
PrimarySiltstone
OtherSandstone, claystone, conglomerate
Location
Coordinates43°00′S 67°30′W / 43.0°S 67.5°W / -43.0; -67.5
Approximate paleocoordinates45°42′S 53°48′W / 45.7°S 53.8°W / -45.7; -53.8
RegionChubut Province
CountryArgentina
ExtentCañadón Asfalto Basin
Type section
Named forSierra La Colonia
La Colonia Formation is located in Argentina
La Colonia Formation
La Colonia Formation (Argentina)

The La Colonia Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.[1]

Originally thought to be Campanian (c.73-72 million years ago) in age or earlier, studies of underlying formations have made a Maastrichtian (70–66 million years ago) age more likely.[2]

Description[edit]

Paleogeography of the Late Cretaceous with La Colonia Formation indicated

It is divided up into three distinct facies, the first is up to 16 metres (52 ft) thick and consists of conglomerate, the second is by far the thickest at over 100 metres (330 ft), consists of siltstone and claystone, with interbeds of claystone/shale and sandstone, the third is less than 10 metres (33 ft) thick and consists of clay, and probably represents a nearshore marine environment.[3]

The paleoflora was known for its aquatic components, Paleoazolla and Regnellidium. However, recent paleobotanical discoveries at the Cañadón del Irupé locality have revealed the presence of a more diverse range of plants associated with these water bodies, including pteridophytes, gymnosperms, and various angiosperms. Among these are fossil leaves and fruits assignable to Nelumbonaceae.[4]

Fossil content[edit]

Restoration of La Colonia Formation

Turtles[edit]

Turtles from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Chelidae gen. nov.[3] sp. nov. Norte de Cerro Bayo 2 Skull and lower jaw; postcranial remains Represents a new genus of chelid
Patagoniaemys[3] P. gasparinae
  • Buitre Chico
  • in and around Norte de Cerro Bayo 2
  • Cerro Bosta
 "skull fragments and several postcranial elements including a nearly complete vertebral column."[5] A meiolaniform
aff. Yaminuechelys[3] Y. gasparinii
  • Norte de Cerro Bayo 2
  • Cerro Bosta
 "Three specimens formed only by postcranial remains (mainly shell fragments)"

Plesiosaurs[edit]

Plesiosaurs from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Chubutinectes[6] C. carmeloi Several vertebrae, ribs, partial pectoral and pelvic girdles, arm and leg bones, and gastroliths An elasmosaurid
Elasmosauridae[3] Indeterminate
  • Norte de Cerro Bayo 1
  • Cerro Bosta
 "three postcranial specimens that preserve cervical, dorsal and caudal vertebrae, ribs and gastroliths and three vertebrae without collection number"
Kawanectes[7] K. lafquenianum "an incomplete mandible, nine cervical vertebrae, 14 dorsal vertebrae, three sacral vertebrae and five caudal vertebrae, and almost complete left fore limb, the isolated right humerus, both femora, ilia, pubes and the right ischium" An elasmosaurid
Sulcusuchus[3] S. erraini Cerro Bosta "part of skull and mandible" A polycotylid

Dinosaurs[edit]

Ornithiscians[edit]

Ornithischians from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Ankylosauria[3] Indeterminate Norte de Cerro Bayo 2 An osteoderm
Hadrosauroidea[3] Indeterminate Norte de Cerro Bayo 2 Metatarsal fragment and two vertebral fragments

Sauropods[edit]

Sauropods from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Somphospondyli[3] Indeterminate Norte de Cerro Bayo 2 "Two fragmentary caudal vertebrae"
Titanomachya[8] T. gimenezi Norte de Cerro Bayo 2 "Partial postcranial skeleton" A titanosaur sauropod

Theropods[edit]

Theropods from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Carnotaurus C. sastrei Pocho Sastre "Nearly complete skeleton and skull"[9] An abelisaurid[10][11]
Enantiornithine[12] Indeterminate A distal humerus
Koleken[3][13] K. inakayali Norte de Cerro Bayo 1 "Quite complete and partially articulated skeleton" An abelisaurid.
Theropoda[3] Indeterminate Norte de Cerro Bayo 2 "Metatarsal fragments of a single individual"

Mammals[edit]

Over 300 mammal specimens have been found in the La Colonia Formation.[14]

Mammals of the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Argentodites A. coloniensis[15] A possible gondwanatherian or multituberculate
Coloniatherium C. cilinskii[16] A meridiolestidan
Ferugliotherium F. windhauseni[15] A possible gondwanatherian or multituberculate
Reigitherium R. bunodontum[17] A meridiolestidan

Snakes[edit]

Fossils of madtsoiids, and perhaps boids, have been found in the formation.[18]

Snakes from the La Colonia Formation
Genus Species Location Stratigraphic position Material Notes Images
Alamitophis A. argentinus[18] Trunk vertebra Madtsoiidae

See also[edit]

References[edit]

  1. ^ Weishampel et al., 2004, pp.600-604
  2. ^ Rauhut, 2003
  3. ^ a b c d e f g h i j k Gasparini, Zulma; Sterli, Juliana; Parras, Ana; O'Gorman, José Patricio; Salgado, Leonardo; Varela, Julio; Pol, Diego (May 2015). "Late Cretaceous reptilian biota of the La Colonia Formation, central Patagonia, Argentina: Occurrences, preservation and paleoenvironments". Cretaceous Research. 54: 154–168. doi:10.1016/j.cretres.2014.11.010.
  4. ^ Gandolfo, Maria A.; Cuneo, Ruben N. (February 2005). "Fossil Nelumbonaceae from the La Colonia Formation (Campanian–Maastrichtian, Upper Cretaceous), Chubut, Patagonia, Argentina". Review of Palaeobotany and Palynology. 133 (3–4): 169–178. doi:10.1016/j.revpalbo.2004.09.007.
  5. ^ Sterli & De la Fuente, 2011
  6. ^ O’Gorman, José P.; Carignano, Ana Paula; Calvo-Marcilese, Lydia; Pérez Panera, Juan Pablo (2023-08-10). "A new elasmosaurid (Sauropterygia, Plesiosauria) from the upper levels of the La Colonia Formation (upper Maastrichtian), Chubut Province, Argentina". Cretaceous Research: 105674. doi:10.1016/j.cretres.2023.105674. ISSN 0195-6671.
  7. ^ O'Gorman, 2019
  8. ^ Pérez-Moreno, A.; Salgado, L.; Carballido, J. L.; Otero, A.; Pol, D. (2024). "A new titanosaur from the La Colonia Formation (Campanian-Maastrichtian), Chubut Province, Argentina". Historical Biology: An International Journal of Paleobiology. doi:10.1080/08912963.2024.2332997.
  9. ^ "Table 3.1," in Weishampel et al., 2004, p.49
  10. ^ Rauhut, 2004
  11. ^ Leanza et al., 2004, p.72
  12. ^ Lawver, Daniel R.; Debee, Aj M.; Clarke, Julia A.; Rougier, Guillermo W. (January 1, 2011). "A New Enantiornithine Bird from the Upper Cretaceous La Colonia Formation of Patagonia, Argentina". Annals of Carnegie Museum. 80 (1): 35–42. doi:10.2992/007.080.0104. S2CID 85015365.
  13. ^ Pol, Diego; Baiano, Mattia Antonio; Černý, David; Novas, Fernando; Cerda, Ignacio A. (21 May 2024). "A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria". WILEY Online Library. doi:10.1111/cla.12583. Retrieved 21 May 2024.
  14. ^ Rougier et al., 2009, p.225
  15. ^ a b Gurovich, Y.; Beck, R. (2009). "The phylogenetic affinities of the enigmatic mammalian clade Gondwanatheria". Journal of Mammalian Evolution. 16 (1): 25–49. doi:10.1007/s10914-008-9097-3. S2CID 42799370.
  16. ^ Rougier, G.W.; Forasiepi, A.M.; Hill, R.V.; Novacek, M. (2009). "New mammalian remains from the Late Cretaceous La Colonia Formation, Patagonia, Argentina". Acta Palaeontologica Polonica. 54 (2): 195–212. doi:10.4202/app.2006.0026.
  17. ^ Rougier, G. W.; Turazzinni, G. F.; Cardozo, M. S.; Harper, T.; Lires, A. I.; Canessa, L. A. (2021). "New Specimens of Reigitherium bunodontum from the Late Cretaceous La Colonia Formation, Patagonia, Argentina and Meridiolestidan Diversity in South America". Journal of Mammalian Evolution. 28 (4): 1051–1081. doi:10.1007/s10914-021-09585-2. S2CID 254704047.
  18. ^ a b Albino, Adriana M. (2000). "New record of snakes from the Cretaceous of Patagonia (Argentina)". Geodiversitas. 22 (2): 247–253.

Bibliography[edit]

Further reading[edit]

  • A. M. Albino. 2000. New record of snakes from the Cretaceous of Patagonia (Argentina). Geodiversitas 22(2):247-253
  • N. R. Cúneo, E. J. Hermsen, and M. A. Gandolfo. 2013. Regnellidium (Salviniales, Marsileaceae) macrofossils and associated spores from the Late Cretaceous of South America. PloSOne 174(3):340-349
  • J. P. O'Gorman, L. Salgado, I. A. Cerda and Z. Gasparini. 2013. First record of gastroliths associated with elasmosaur remains from La Colonia Formation (Campanian–Maastrichtian), Chubut, Patagonia Argentina, with comments on the probable depositional palaeoenvironment of the source of the gastroliths. Cretaceous Research 40:212-217
  • J. O'Gorman and Z. Gasparini. 2013. Revision of Sulcusuchus erraini (Sauropterygia, Polycotylidae) from the Upper Cretaceous of Patagonia, Argentina. Alcheringa 37(2):163-176
  • T. Harper, A. Parras, and G. W. Rougier. 2018. Reigitherium (Meridiolestida, Mesungulatoidea) an Enigmatic Late Cretaceous Mammal from Patagonia, Argentina: Morphology, Affinities, and Dental Evolution. Journal of Mammalian Evolution
  • Z. Kielan-Jaworowska, E. Ortiz-Jaureguizar, C. Vieytes, R. Pascual, and F. J. Goin. 2007. First cimolodontan multituberculate mammal from South America. Acta Palaeontologica Polonica 52(2):257-262
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