Yecua Formation
Geologic formation in Bolivia
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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]
UnderliesTariquia Formation
OverliesPetaca Formation
Thickness~50–300 m (160–980 ft)
| Yecua Formation | |
|---|---|
| Stratigraphic range: Late Langhian-Early Messinian (Colloncuran-Huayquerian) ~ | |
| 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 |
Bivalves
Gastropods
| Name | Species | Member | Material | Notes |
|---|---|---|---|---|
| cf. Gyrodes or Natica sp.[1] | ||||
| cf. Turritella[1] | cf. T. sp | |||
Crustaceans
Vertebrates
| Name | Species | Member | Material | Notes | Image |
|---|---|---|---|---|---|
| cf. Theosodon[1] | cf. T. sp | distal limb bone | a litoptern |  | |
| Rodentia indet.[1] | tooth | ||||
| Mourasuchus[3] | M. sp. | skull fragments, partial vertebrae & ribs | |||
| Pleurodira[3] | shell elements | ||||
| Humboldtichthys[4] | Humboldtichthys kirschbaumi | incompletely preserved anterior portion of the body and posterior head | a Glass Knifefish | ||
| Siluriformes indet.[1] | possibly Ariidae | ||||
| Characiformes or Clupeiformes[1] | a scale | ||||