Publication Date: 2013.
Author affiliation: Ibiricu, Lucio M. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Nacional Patagonico; Argentina
Author affiliation: Martinez, Ruben D. Universidad Nacional de la Patagonia "san Juan Bosco"; Argentina
Author affiliation: Casal, Gabriel A. Universidad Nacional de la Patagonia "san Juan Bosco"; Argentina
Author affiliation: Cerda, Ignacio A. Universidad Nacional de Rio Negro. Sede Alto Valle; Argentina
Author affiliation: Cerda, Ignacio A. Instituto de Investigaciones En Paleobiologia y Geologia; Argentina
Background:Central Patagonia, Argentina, preserves an abundant and rich fossil record. Among vertebrate fossils from theUpper Cretaceous Bajo Barreal Formation of Patagonia, five individuals of the small, non-avian theropod dinosaurAniksosaurus darwiniwere recovered. Group behavior is an important aspect of dinosaur paleoecology, but it is not well-documented and is poorly understood among non-avian Theropoda.Methods/Principal Findings:The taphonomic association of individuals from the Bajo Barreal Formation and aspects oftheir bone histology suggest gregarious behavior forAniksosaurus, during at least a portion of the life history of this species.Histology indicates that the specimens were juvenile to sub-adult individuals. In addition, morphological differencesbetween individuals, particularly proportions of the appendicular bones, are probably related to body-size dimorphismrather than ontogenetic stage.Conclusions/Significance:Gregarious behaviour may have conferred a selective advantage onAniksosaurusindividuals,contributing to their successful exploitation of the Cretaceous paleoenvironment preserved in the Bajo Barreal Formation.The monospecific assemblage ofAniksosaurusspecimens constitutes only the second body fossil association of small,coelurosaurian theropods in South America and adds valuable information about the paleoecologies of non-avian theropoddinosaurs, particularly in the early Late Cretaceous of Patagonia.
Repository: RID-UNRN (UNRN). Universidad Nacional de Río Negro