Amargatitanis

Amargatitanis (meaning "Amarga giant") is a genus of dicraeosaurid sauropod dinosaur (a type of large, long-necked quadrupedal herbivorous dinosaur) from the Barremian-aged (Lower Cretaceous) La Amarga Formation of Neuquén, Argentina. It is known from a single, incomplete postcranial skeleton consisting of a partial hindlimb, ischium, and two vertebrae. These remains were unearthed by Argentine paleontologist José Bonaparte in 1983 during an expedition by the Museo Argentino de Ciencias Naturales and later described as a new genus and species, Amargatitanis macni by Sebastián Apesteguía. The genus name comes from the words Amarga, where the fossils were collected, and titanis meaning "titan". Its species name is in reference to the MACN (Museo Argentino de Ciencias Naturales), where the remains are stored.

Though initially thought to be a titanosaur, recent research has found it to be a dicraeosaurid, a group of short-necked, smaller sauropods. It reached around 12 meters (39.7 feet) long and according to one estimate. Like other dicraeosaurids, it has robust limbs, a long tail, and tall . However, much of its anatomy can only be inferred due to the lack of preserved bones. It lived in a diverse ecosystem that included higher browsing titanosauriforms and smaller, lower browsing dicraeosaurids like Amargatitanis itself.