WThe Angostura Formation is a Late Miocene geologic formation of the Borbón Basin in northwestern Ecuador.
WThe Biblián Formation is an Early Miocene geologic formation of the Cuenca Basin in Ecuador. Fossils of Xenastrapotherium aequatorialis have been found in the formation.
WThe Canoa Formation is a Piacenzian to Calabrian geologic formation in Ecuador. The sandstones were deposited in a coastal environment. The formation is correlated to the Charco Azul Formation of western Panama and southeastern Costa Rica.
WThe Esmeraldas Formation is an Early Pliocene geologic formation of the Borbón Basin in northwestern Ecuador.
WThe Jama Formation is a Pliocene to Early Pleistocene geologic formation in Ecuador. The claystones and sandstones were deposited in an coastal environment. The age of the Jama Formation is constrained by 40Ar/39Ar dating of tephra beds. The formation is correlated to the Charco Azul Formation of western Panama and southeastern Costa Rica.
WThe Letrero Formation is a Late Miocene geologic formation in south-central Ecuador. The formation comprises lacustrine sediments with strong fluvial clastic input and contains siltstones and fine-grained sandstones.
WThe Onzole Formation is an Early Pliocene geologic formation in the Borbón Basin of northwestern Ecuador. The formation consists of a shallow marine sandstone member containing many fish fossils, among which megalodon, and a deep water member comprising tuffaceous shales and mudstones containing gastropods, bivalves and scaphopods.
WThe Viche Formation is a Langhian geologic formation of the Borbón Basin in northwestern Ecuador. The formation underlies the Angostura Formation. Fossils of Ziphiidae indet. have been found in the formation.
WXenastrapotherium is an extinct genus of astrapothere, a type of hoofed herbivorous mammal, native to South America, which lived in the Middle to Late Miocene period, typically during the Laventan stage. It is a member of the family Astrapotheriidae in the subfamily Uruguaytheriinae, large astrapotheres, equipped with a trunk-like nose and protruding teeth, similar to the elephants, but their tusks were the canine teeth, not the incisors. Xenastrapotherium was a genus widely distributed in northern South America, in contrast to other species of astrapotheres which lived in the area of the Southern Cone of the continent. It differed from other astrapotheres by having two lower incisors on each side of the jaw and the tusks have a pronounced longitudinal curvature, although their general shape and size are probably very similar to Astrapotherium, whose weight would be 900 to 1,500 kilograms, comparable to the current black rhino.