Constraining Quadrupedal Launch: Range of Motion in Coloborhynchus robustus B Griffin¹, E Martin-Silverstone¹, O Demuth¹, C Palmer¹, E J Rayfield^{1 1} University of Bristol ben.dinosaur@gmail.com Pterosaurs reached sizes significantly larger than any modern flyer and as a result there is uncertainty whether the largest pterosaurs were capable of flight. The quadrupedal launch hypothesis proposes that pterosaurs circumvented the size restriction seen in modern flyers by using their fore- and hindlimbs to generate sufficient thrust to propel the body into the air during take-off. Here we investigate the ability of the mid-sized ornithocheirid Coloborhynchus robustus to assume the poses required to utilise the quadrupedal launch hypothesis. We applied range of motion (ROM) mapping methodology to the pelvic and pectoral girdles to identify unviable poses at varying levels of appendicular cartilage based on an extant phylogenetic bracket model. The ROM of each girdle were further constrained by utilising the novel Triangulated Minimum Stretch (TMS) methodology, identifying the connective tissue constrained ROM. We found that the pelvic girdle could assume the required poses for quadrupedal launch, requiring offset from appendicular cartilage equivalent to an ostrich, while the pectoral girdle requires appendicular cartilage equivalent to modern alligators. The connective tissue ROM for the pelvic girdle found that the poses required for quadrupedal launch could be reached with low levels of ligamentous stretch. The pectoral girdle investigation revealed the poses required for quadrupedal launch could be reached with muscular stretch values equivalent to modern birds. Our study indicates that Coloborhynchus robustus would be capable of assuming the poses required to launch utilising the quadrupedal launch hypothesis.