Bajo de la Carpa Formation

Bajo de la Carpa Formation
Stratigraphic range: Mid-Late Santonian
~86–83 Ma
↓
Juan D. Porfiri excavating the holotype of Diuqin lechiguanae from the Bajo de la Carpa Formation
TypeGeological formation
Unit ofNeuquén Group
 Río Colorado Subgroup
UnderliesAnacleto Formation
OverliesRío Neuquén Subgroup
 Plottier Formation
ThicknessUp to 150 m (490 ft)
Lithology
PrimarySandstone
OtherMudstone, siltstone, paleosol
Location
Coordinates38°48′S 68°48′W / 38.8°S 68.8°W / -38.8; -68.8
Approximate paleocoordinates43°24′S 49°48′W / 43.4°S 49.8°W / -43.4; -49.8
RegionNeuquén & Río Negro Provinces
CountryArgentina
ExtentNeuquén Basin
Bajo de la Carpa Formation is located in Argentina
Bajo de la Carpa Formation
Bajo de la Carpa Formation (Argentina)

The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that crops out in northern Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the oldest of two formations belonging to the Río Colorado Subgroup within the Neuquén Group. Formerly, that subgroup was treated as a formation, and the Bajo de la Carpa Formation was known as the Bajo de la Carpa Member.[1]

At its base, this formation conformably overlies the Plottier Formation of the older Río Neuquén Subgroup, and it is in turn overlain by the Anacleto Formation, the youngest and uppermost formation of the Neuquén Group.[2][3]

The Bajo de la Carpa Formation can reach 150 metres (490 ft) in thickness in some locations, and consists mainly of sandstones of various colors, all of fluvial origin, with thin layers of mudstone and siltstone in between. Geological features such as geodes, chemical nodules, impressions of raindrops, and paleosols (fossil soils) are commonly found in this formation as well.[1][3]

Fossil content

Reptiles

Reptiles reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Lomalatachelys[4] L. neuquina A snake-necked turtle
Dinilysia D. patagonica A Snake
Paleochelco[5] P. occultato A lizard
Podocnemidoidea[6] Indeterminate.

Small nests with eggs inside, found in this formation, probably belonged to the bird Neuquenornis.[3] Fossil wasp nests have also been found in these rocks.[1][3]

Crocodylomorphs

Crocodylomorphs reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Barrosasuchus B. neuquenianus[7]
Comahuesuchus C. brachybuccalis
Cynodontosuchus C. rothi
Lomasuchus L. palpebrosus.
Gasparinisuchus[8] G. peirosauroides
Kinesuchus K. overoi[9]
Neuquensuchus N. universitas [10]
Notosuchus N. lepidus
N. terrestris
Peirosaurus P. torminni A fragmentary skull and a partial postcranial skeleton.

Fish

Fish reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Rinconodus[11] R. salvadori A ceratodontid lungfish

Dinosaurs

Ornithischians

Ornithischians reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Ankylosauria[12] Indetermidate.
Mahuidacursor[13] M. lipanglef An ornithopod.

Sauropods

Sauropods reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Bonitasaura B. salgadoi A partial sub-adult skeleton with a lower jaw, a partial vertebrae series, and limb bones. A titanosaur.
Inawentu I. oslatus Rincón de los Sauces. A partially articulated skeleton, including a nearly complete skull, Several vertebrae from the atlas to the end of the sacrum, and both ilia A titanosaur.
Overosaurus O. paradasorum Upper A fully articulated vertebral series consists of rib bones, dorsals, and ilium. A titanosaur.
Rinconsaurus R. caudamirus Rincón de los Sauces. Lower. The fossil remains included vertebrae, limb bones, scapula, hip bones (pubis, ilium, and ischium) and several ribs. A titanosaur.
Traukutitan[14] T. eocaudata Sitio Trauku. Lower A partial semi-articulated skeleton including both thigh bones and thirteen vertebrae from the anterior and middle tail. A titanosaur.

Theropods

Theropods reported from the Bajo de la Carpa Formation
Genus Species Location Stratigraphic position Material Notes Images
Achillesaurus A. manazzonei Upper A partial skeleton consists of a sacral vertebra, four tail vertebrae, part of the left thighbone, shin, and foot, and the left ilium. An alvarezsaurid.
Alvarezsaurus A. calvoi An alvarezsaurid.
Diuqin[15] D. lechiguanae "the isthmus between the southeast coast of Lago Barreales and the northwest coast of Lago Mari Menuco" A fragmentary but associated partial skeleton An unenlagiine.
Llukalkan [16] L. aliocranianus La Invernada site. A partial skull. An abelisaur.
Neuquenornis[3] N. volans Upper A skull and a partial postcranial remains. A enantiornithine bird.
Patagopteryx P. eferrariisi Upper The oldest known flightless bird.
Tratayenia[17] T. rosalesi A well-preserved partial skeleton A megaraptoran theropod.
Velocisaurus[16] V. unicus A noasaur.
Viavenator[16] V. exxoni An abelisaur.

See also

References

  1. ^ a b c Sánchez et al., 2006
  2. ^ Fossa Mancini et al., 1938
  3. ^ a b c d e Leanza et al., 2004
  4. ^ F. d.e. Lapparent de Broin and M. S. de la Fuente. 2001. Oldest world Chelidae (Chelonii, Pleurodira), from the Cretaceous of Patagonia, Argentina. C. R. Acad. Sci. Paris, Sciences de la Terre et des planètes 333:463-470.
  5. ^ Martinelli, Agustín Guillermo; Agnolin, Federico; Ezcurra, Martin (2021-07-26). "Unexpected new lizard from the Late Cretaceous of southern South America sheds light on Gondwanan squamate diversity". Revista del Museo Argentino de Ciencias Naturales. Nueva Serie. 23 (1): 57–80. doi:10.22179/revmacn.23.716. hdl:11336/167951. ISSN 1853-0400. S2CID 243557642.
  6. ^ Maniel, I. J. (2024). "Pelomedusoid turtles from the Bajo de la Carpa Formation (Santonian, Upper Cretaceous), Río Negro Province, Patagonia, Argentina". Ameghiniana. 61 (3): 138–147. doi:10.5710/AMGH.12.06.2024.3591.
  7. ^ Coria et al., 2019
  8. ^ Martinelli et al., 2012
  9. ^ Filippi et al., 2018a
  10. ^ Lio et al., 2018
  11. ^ Panzeri, K. M.; Gouiric Cavalli, S.; Cione, A. L.; Filippi, L. S. (2022). "Description of the first Cretaceous (Santonian) articulated skeletal lungfish remains from South America, Argentina". Comptes Rendus Palevol. 21 (37): 815–835. doi:10.5852/cr-palevol2022v21a37. S2CID 253034856.
  12. ^ Rozadilla, Sebastián; Agnolín, Federico; Manabe, Makoto; Tsuihiji, Takanobu; Novas, Fernando E. (September 2021). "Ornithischian remains from the Chorrillo Formation (Upper Cretaceous), southern Patagonia, Argentina, and their implications on ornithischian paleobiogeography in the Southern Hemisphere". Cretaceous Research. 125: 104881. Bibcode:2021CrRes.12504881R. doi:10.1016/j.cretres.2021.104881. ISSN 0195-6671.
  13. ^ Cruzado Caballero et al., 2019
  14. ^ Filippi, Leonardo S.; Juárez Valieri, Rubén D.; Gallina, Pablo A.; Méndez, Ariel H.; Gianechini, Federico A.; Garrido, Alberto C. (2023). "A rebbachisaurid-mimicking titanosaur and evidence of a Late Cretaceous faunal disturbance event in South-West Gondwana". Cretaceous Research. 154. doi:10.1016/j.cretres.2023.105754. ISSN 0195-6671.
  15. ^ Porfiri, Juan D.; Baiano, Mattia A.; dos Santos, Domenica D.; Gianechini, Federico A.; Pittman, Michael; Lamanna, Matthew C. (2024-06-14). "Diuqin lechiguanae gen. et sp. nov., a new unenlagiine (Theropoda: Paraves) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina". BMC Ecology and Evolution. 24 (1): 77. Bibcode:2024BMCEE..24...77P. doi:10.1186/s12862-024-02247-w. ISSN 2730-7182. PMC 11177497. PMID 38872101.
  16. ^ a b c Filippi et al., 2018b
  17. ^ Porfiri et al., 2018

Bibliography

Further reading