INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
New sauropod dinosaurs from the Late Cretaceous of Mendoza Province, Neuquén Basin, Argentina
GONZÁLEZ RIGA, BERNARDO J.
Congreso; 69th Annual meeting of the Society of Vertebrate Paleontology; 2009
Society of Vertebrate Paleontology
In the last year, new sauropod species were discovered in Mendoza Province, northern Neuquén basin. In this region, the Neuquén Group and the Loncoche Formation represent two Late Cretaceous different paleoecological scenarios. In the first scenario, the Neuquén Group (Albian-early Campanian) comprises a thick fluvial, playa-lake and eolian deposits. In this facies we found two new sauropods: Mendozasaurus neguyelap and Malarguesaurus florenciae. Malarguesaurus is a robust somphospondylian titanosauriform recovered in Paso de las Bardas and has an unusual morphology: procoelous distal caudal centra associated with procoelous-opisthoplatyan proximal caudals. Mendozasaurus was discovered in Cerro Guillermo area. It is an armored lithostrotian titanosaur collected in a taphonomic mode named oberbank bone assemblage, associated to crevasse splay facies. Mendozasaurus shows a relatively short, wide and robust neck and shares cervical characters with Futalongkosaurus dukei from Neuquén Province. Moreover, articulated pes of new specimens discovered in this area, give us information about the progressive reduction of size and number of pedal phalanges, in comparison with other titanosaurs exceptionally preserved (La Invernada unnamed species, Allen Formation, Neuquén Province, and Epachthosaurus sciuttoi, Chubut Province). In the second scenario, the Loncoche Formation (late Campanian-early Masstrichtian) includes lacustrine and marine marginal facies related to a first Atlantic ingression that covered Patagonia. In a level of Agua del Choique site, 14 km west of Malargue City, we located a mega tracksite that includes more than 250 sauropod footprints and some theropod tracks. This finding is an excellent example of wide-gauge style of locomotion produced by derived titanosaurs (probably middle size saltasaurine or aeolosaurine titanosaurs). Moreover, most of trackways analyzed show the same direction, suggesting that Late Cretaceous titanosaurs from Mendoza traveled in social group.