Fil: Lecuona, Agustina. Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología. Río Negro, ArgentinaFil: Lecuona, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Buenos Aires, Argentina.Most fossil vertebrates are known by their hard-tissues,but inferring their soft-tissues is important to elaborate a bigger picture ofthem. Muscular reconstructions in fossil vertebrates are mostly focused on mammalsand dinosaurs, whereas two such studies were recently performed within the crocodilian-lineageof archosaurs, in the pseudosuchians Poposaurusand Prestosuchus. The most accuratemethodology for soft-tissue reconstruction is the EPB, combining phylogeny,osteological correlates, and living relatives comparison. The pelvis andhindlimb musculature of the exquisitely preserved pseudosuchian Batrachotomus is presented here. Most muscleswere inferred with low speculation; in more than one third of the attachments,the inferences were the least speculatives (e.g.,origin of Mm. ambiens and gastrocnemius); other muscles present morespeculation because the avian homologue is quite different, but theirreconstruction is based on similarities with crocodilians (e.g., Mm. pubo-ischio-tibialiset fibulares). The lower leg and foot soft-tissues inferences are very speculative, includingsome muscles unable to reconstruct (e.g.,digit flexors and extensors) due to the scarce information and the broaddifferences with birds. Differences in some muscles like iliotibiales and iliofemoralisorigins and puboischiofemoralis internus1attachments were noted with Poposaurus,but shearing the same condition with Prestosuchus.Similarities between Batrachotomusand Prestosuchus are expected bytheir close phylogenetic affinity and also probably by their quadrupedallocomotion and associated paleobiological traits, contrasting with the biped poposauroidPoposaurus. This muscularreconstruction will allows us to face other studies (e.g. morphofunctional) relevant to understand Batrachotomus paleobiology, and eventually study the evolutionarypatterns of the stance and gait within Pseudosuchia.