Monster of Aramberri
During the early 2000s, a new excavation campaign unearthed several additional fossils of the animal, in which some of them were subsequently 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.
Based on various comparisons and descriptions, the "Monster of Aramberri" is most likely a representative of the Thalassophonea, a derived clade of pliosaurids characterized by a short neck and a large, elongated skull.
The gastralia (abdominal ribs) of the Aramberri pliosaur possess traits that could be diagnostic for a distinct pliosaurid lineage that may soon be described.
In the trunk, the Aramberri pliosaur preserves fossils of what appears to be an ichthyosaur, suggesting that this was its last prey consumed before its death.
The La Caja Formation, where the "Monster of Aramberri" was discovered, contains abundant marine fossils from a shallow environment dating from the Kimmeridgian stage of the Late Jurassic.
[4][5][6] The inaccessibility of the place and the fossils collected at the time weighing around 200 kg (440 lb) in total, prevented researchers from moving it immediately.
The following year, the discovered material was finally moved over 1.24 miles (2.00 km) via fairly complex technical processes before reaching a road facilitating transport.
[4] Subsequently, the two large concretions were sent to the Faculty of Earth Sciences of the Autonomous University of Nuevo León, where the fossils concerned are all cataloged under the specimen number UANL-FCT-R2.
Despite the fact that the specimen was discovered in marine sediments, Hähnel identified it as a carnivorous dinosaur with a length ranging between 10 and 15 m (33 and 49 ft).
[4] In 2001, paleontologists announced via a publication that they had re-identified the specimen as actually coming from an imposing marine reptile of the family Pliosauridae on the basis of its vertebral morphology, while also pointing out that the fossils should be described in more detail later.
[5][6] From 2001 to 2007, new expeditions carried out in the type locality by Mexican, French and German paleontologists helped by residents of the city, made it possible to exhume the caudal part of the specimen, and two thirds of the skeleton.
[3][15] In 2003, in order to help paleontologists, the newly elected mayor of Nuevo León sended a helicopter to transport a fossil block weighing a total of 450 kg (990 lb).
[9][16][10][17] In a news article published in November 2012, paleontologist Javier Aguilar Pérez expressed that the specimen should receive a skeletal mount formed from the fossils once their preparations are completed.
[21][22] The "Monster of Aramberri", as its nickname suggests, is also one of the largest pliosaurs identified to date, but its size estimates have declined considerably over years.
[9][10] In 2008, Adam S. Smith and Gareth J. Dyke, citing the source of Buchy and colleagues (2003), give a maximum length of 17 m (56 ft).
[24] In his thesis published a year later, in 2009, Australian paleontologist Colin McHenry criticizes this interpretation, which he finds very exaggerated.
[26] The "Monster of Aramberri" was initially described as a large dinosaur by Hähnel (1988) without more precise classifications, its carnivorous nature suggesting a probable theropod.
In 2009, based on its vertebral morphology, McHenry did not consider the Aramberri specimen to be close to Kronosaurus, casting doubt on the classification later proposed by Frey and Stinnesbeck.
[5] However, Buchy questioned this interpretation in 2007, citing that very few pliosaur fossils have been found with neural arches fused to the vertebrae, and that these were most likely juvenile traits carried over into adulthood.
Conversely, the jugal would have been perforated by a tooth which would have reached two-thirds of that which had touched the pterygoid, but which would have probably been fatal because there are no signs of healing.
The animal that would have injured or even killed the Aramberri pliosaur would probably have been larger, but the authors did not give estimates of its size in order to avoid speculations.
[2][9][13][17] At the trunk level, the Aramberri specimen shows what appear to be poorly preserved bones with etching traces from a possible ichthyosaur.
[26] The La Caja Formation, where the "Monster of Aramberri" was discovered, would have been a calm marine environment of shallow depth estimated between 150 and 300 m (490 and 980 ft), although the proximity of an island is attested by plant deposits probably torn away during rare storms.
[5] The presence of this imposing pliosaurid in this region is an argument in favor of the existence of a connection between the northern Tethyan domain where most of the fossils were found, and the epicontinental seas which covered South America at that time.
