Yecua Formation

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Yecua Formation
Stratigraphic range: Late Langhian-Early Messinian
(Colloncuran-Huayquerian)
~14–7  Ma
Underlies Tariquia Formation
Overlies Petaca Formation
Thickness~50–300 m (160–980 ft)
Lithology
Primary Mudstone, Sandstone [1]
Other Gypsum
Location
Region Chaco Basin
Country Bolivia

The Yecua Formation is a geological Formation in what is now Bolivia. Studies suggest that the Yecua Formation preserves a coastal setting with humid to semiarid floodplains, shorelines and tidal as well as shallow marine environments including marshes, streams, lakes and brackish bodies of water. There may have been a connection to the Amazon Basin or the Paranaense Sea. [2]

Contents

Bivalves

NameSpeciesMemberMaterialNotes
Tellina [1] T. sp
cf. Cyrena [1] cf. C. sp
cf. Astarte [1] cf. A. sp
cf. Lucina [1] cf. L. sp
Senis [1] S. cf. elongatus
cf. Corbula or Cymbophora sp. [1] cf. C. sp
cf. Nucula [1] cf. N. sp

Gastropods

NameSpeciesMemberMaterialNotes
cf. Gyrodes or Natica sp. [1]
cf. Turritella [1] cf. T. sp

Crustaceans

NameSpeciesMemberMaterialNotes
Bythocypris [1] B. sp
Cyprideis [1] C. sp
cf. Balanus [1] cf. B. sp
indetermined crabs [1]

Vertebrates

NameSpeciesMemberMaterialNotesImage
cf. Theosodon [1] cf. T. spdistal limb bonea litoptern
Theosodon NT.jpg
Rodentia indet. [1] tooth
Mourasuchus [3] M. sp.skull fragments, partial vertebrae & ribs
Pleurodira [3] shell elements
Humboldtichthys [4] Humboldtichthys kirschbaumiincompletely preserved anterior portion of the body and posterior heada Glass Knifefish
Siluriformes indet. [1] possibly Ariidae
Characiformes or Clupeiformes [1] a scale

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Marshall, L.G.; Sempere, T.; Gayet, M. (1993). "The Petaca (Late Oligocene - Middle Miocene) and Yecua (Late Miocene) Formations of the Subandean-Chaco Basin, Bolivia, and their Tectonic Significance". Travaux et Documents des Laboratoires de Géologie de Lyon. 125: 291–301.
  2. ↑ Hulka, C.; Gräfe, K.U.; Sames, B.; Uba, C.E.; Heubeck, C. (2006). "Depositional setting of the Middle to Late Miocene Yecua Formation of the Chaco Foreland Basin, southern Bolivia". Journal of South American Earth Sciences. 21 (1–2): 135–150. Bibcode:2006JSAES..21..135H. doi:10.1016/j.jsames.2005.08.003.
  3. 1 2 Tineo, D.E.; Bona, P.; Pérez, L.M.; Vergani, G.D.; González, G.; Poiré, D.G.; Gasparini, Z.; Legarreta, P. (2015). "Palaeoenvironmental implications of the giant crocodylian Mourasuchus (Alligatoridae, Caimaninae) in the Yecua Formation (late Miocene) of Bolivia". Alcheringa . 39 (2): 1–12. Bibcode:2015Alch...39..224T. doi:10.1080/03115518.2015.967162. hdl: 11336/33274 . S2CID   129930697.
  4. ↑ Albert, J.S.; Fink, W.L. (2010). "Phylogenetic relationships of fossil neotropical electric fishes (Osteichthyes: Gymnotiformes) from the upper Miocene of Bolivia". Journal of Vertebrate Paleontology. 27 (1): 17–25. doi:10.1671/0272-4634(2007)27[17:PROFNE]2.0.CO;2. S2CID   35007130.
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