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Copyright of Journal of Neotropical Mammalogy / Mastozoologia Neotropical is the property of Sociedad Argentina para el Estudio de los Mamiferos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The stance of pterosaurs on land is traditionally a controversial question. Here, we show that pterosaurs likeAnhanguera piscatorwere quadrupeds. An osteological model ofA. piscatorwas three-dimensionally built in digital space. The reconstructed muscles of its pelvic girdle were then placed on their points of origin and insertion to allow the biomechanical calculations to find the most efficient stance on land to be performed. The hindlimb readjustment (i.e. the repositioning of the hindlimb according to the achieved results) led to a pelvic counterclockwise displacement at 10°, which means that the ilium previously placed at 0° regarding an axis parallel to the ground was moved (and so the whole pelvis) 10° up from the preacetabular process. This new position preventsA. piscatorfrom having a fully upright stance. A 10° displacement of the pelvic girdle would compel the forelimbs to be highly sprawled. Therefore, this study affordsA. piscatorhaving a quadrupedal gait and demonstrates that a bipedal stance is not viable once the lever arm values decrease abruptly both for extensor and flexor muscles during the femoral extension. This is the first time this approach is used to shed light on this question. [ABSTRACT FROM PUBLISHER]