Monster of Aramberri

The "Monster of Aramberri" is an informal name given to a fossil skeleton of a very large pliosaur since numbered as UANL-FCT-R2, of which the first remains were discovered in 1985 near the town of Aramberri, Mexico. In scientific literature, some authors also refer to it as the Aramberri pliosaur or the Aramberri specimen. Initially interpreted as a dinosaur in 1988, it was formally reidentified as a marine reptile of the family Pliosauridae in a short 2001 publication. Initially, only two concretions containing the animal's fossils were discovered, with one of the two—containing the fossils of a rostrum and teeth—later noted as lost in the first in-depth study conducted on the specimen in 2003. During the 2000s, a new excavation campaign unearthed several additional fossils of the animal. Subsequently, most of these fossils were sent to Karlsruhe State Museum of Natural History, Germany, to be prepared, before returning them in 2012 to the Autonomous University of Nuevo León, where they are mainly stored. Another significant portion of the fossils are currently stored in the Desert Museum of Saltillo.

The "Monster of Aramberri" is one of the largest pliosaurs ever discovered, but estimates of its size have dropped considerably over the years. Initial estimates set a length of around 15 m (49 ft) based on the assumption that it represents a juvenile, with maximum proposed length estimates up to 18 m (59 ft). Its informal attribution to Liopleurodon by the BBC was linked with the massively over-sized, 25 m (82 ft) long depiction of this genus in the BBC documentary series Walking with Dinosaurs, though the specimen itself wasn't part of the inspiration behind the series' portrayal.