Monster of Aramberri

The "Monster of Aramberri" is the informal name given to UANL-FCT-R2, a giant fossil specimen of a Pliosaur from the La Caja Formation in Aramberri, Nuevo León, Mexico by a student of the Facultad de Ciencias de la Tierra of the Universidad Autónoma de Nuevo León while conducting geological mapping in 1985.^[1] Its alleged (but never confirmed) referral to the genus Liopleurodon served as part of the basis for the inaccurate, gigantic specimen of Liopleurodon depicted in the BBC documentary miniseries Walking With Dinosaurs.^[2]

The remains were originally estimated as pertaining to an individual of approximately 15 m (49 ft) in length and 50 t in body mass^[3] that was furthermore proposed to be as a juvenile ^[4], all of which have been questioned by more recent works ^[5]), claims of the specimen being 18 m (59 ft) long were created by media.^[6] The Monster of Aramberri was initially incorrectly referred to as Liopleurodon ferox ^[7], but, as of 2024, no generic assignment has formally published. French and German paleontologists classified it as a giant pliosaur, which lived around 140 million years ago in shallow waters of the area, in what is now Aramberri, Mexico.^[1]

The Monster of Aramberri remains possibly one of the largest pliosaurs known, and possibly the largest,^[6] even though recent size estimates that compare the cervical vertebrae of the Aramberri pliosaur with those of Kronosaurus (possibly a close relative^[8]) yield smaller estimates, with a mean length estimate of 11.7 metres (38 ft) and a mean body mass approaching 15 metric tons (17 short tons).^[5] In 2021, Spindler and Mattes proposed an even smaller length estimate of 10–11 metres (33–36 ft).^[9]

The director of excavation was José Guadalupe López-Oliva from the Facultad de Ciencias de la Tierra de la UANL. Other specialists involved were Wolfgang Stinnesbeck from the Faculty of Geosciences of Karlsruhe Institute of Technology, and Eberhard Frey and Marie-Céline Buchy of the State Museum of Natural History Karlsruhe, Germany.^[10]

In 2001, the site was evaluated and dispersed remains were recovered. The stratum which contains pliosaur remains was identified. In 2002, a specific excavation began, supported by local people, to cleanse the sediment which contains bone remains of different sizes. Some remains were sent to the Museum of Natural History of Karlsruhe.^{[citation needed]}

On January 3, 2003, remains of the Monster of Aramberri arrived in Karlsruhe, boxed in 14 huge containers^{[citation needed]}. The Museum of Natural History of the city of Karlsruhe was the place assigned for its reconstruction. The bones would be prepared by the specialists of the Museum in order to copy them. Copies would stay at the Museum, while originals would return to Mexico.^{[citation needed]}

As the Museum of Natural History of Karlsruhe could not accept any more remains because it was at its maximum capacity, new remains were sent to the Museo del Desierto in Saltillo, Coahuila, also in Mexico, where they specialise in marine reptiles, Dra. Marie Buchy, is still studying them. Nowadays, part of the fossil is on display at Museo de Historia Mexicana, in a temporary exposition called "Fósiles Marinos de Nuevo Léon, antes mar, ahora montañas".^[11]

In November 2012, after 27 years from its discovery spent on expositions and research, the "Monster of Aramberri" remains were transferred to Facultad de Ciencias de la Tierra from UANL located at Linares, Nuevo León, México.^[12]