Letrero Formation

Letrero Formation
Stratigraphic range: Late Miocene
(Mayoan-Montehermosan)
~11.6–5.3 Ma
TypeGeological formation
Lithology
PrimarySiltstone
OtherSandstone
Location
Coordinates3°18′S 79°06′W / 3.3°S 79.1°W / -3.3; -79.1
Approximate paleocoordinates3°42′S 77°24′W / 3.7°S 77.4°W / -3.7; -77.4
RegionAzuay Province
CountryEcuador
ExtentSierra Region
Letrero Formation is located in Ecuador
Letrero Formation
Letrero Formation (Ecuador)

The Letrero Formation is a Late Miocene (Mayoan to Montehermosan in the SALMA classification) geologic formation in south-central Ecuador. The formation comprises lacustrine sediments with strong fluvial clastic input and contains siltstones and fine-grained sandstones.

Fossil content

Mammals

Mammals of the Letrero Formation
GenusSpeciesLocationMaterialNotesImages
Litopterna Indeterminate RHM Locality 4 A litoptern.
Caviomorpha Indeterminate A caviomorph rodent.
Nabondasypus Nabondasypus maddeni Nabón basin Several osteoderms. An armadillo.
Anadasypus A. aequatorianus RHM Locality 4 A member of cingulata.
Toxodontia Indeterminate A toxodont.

See also

References

  1. 1 2 3 4 RHM Locality 4 at Fossilworks.org
  2. ↑ Barasoain, D.; Zurita, A. E.; Carrión, J. L.; Ñauñay Michilena, D. A.; Luna, C. A.; Miño-Boilini, A. R. (2026). "New endemic Dasypodidae (Xenarthra, Cingulata) from the Late Miocene of Ecuador and the importance of the tropics in the cladogenesis of armadillos". Journal of Systematic Palaeontology. 24 2648714. doi:10.1080/14772019.2026.2648714.
  3. ↑ Carlini et al., 2014

Bibliography