of locomotion. Thrusting with only the hind limbs, as in swimming frogs, was also considered an inefficient form of locomotion for a large animal such as Tanystropheus, although a later study found support for this hypothesis. Renesto (2005) argued that the neck of Tanystropheus was lighter than previously suggested, and that the entire front half of the body was more lightly-built than the rear half, which would have possessed a large amount of muscle mass. In addition to strengthening the hind limbs, the large hip and tail muscles would have shifted the animal's center of mass rearwards, stabilizing the animal as it maneuvered its elongated neck. Weak development of cervical spines suggest that epaxial musculature was underdeveloped in Tanystropheus, and that intrinsic back muscles (e.g., m. longus cervicis) were the driving force behind neck movement. The horizontal overlap between zygapophyses would have limited lateral movement of the neck, while cervical ribs would have formed a brace along the underside of the neck. The long cervical ribs may have played a similar role to ossified tendons of many large dinosaurs, transmitting the forces from the weight of head and neck down to the pectoral girdle, as well as providing passive support by limiting dorsoventral flexion. In 2015, paleoartist Mark Witton estimated that the neck made up only 20% of the entire animal's mass due to its light and hollow vertebrae. By comparison, in pterosaurs of the family Azhdarchidae, which were clearly large terrestrial predators, the neck and head made up almost 50% of their mass. Tanystropheus was also poorly equipped for aquatic life, with the only adaptation being a lengthened fifth toe, which suggests that it visited the water some of the time, though was not wholly dependent on it. Witton proposed that Tanystropheus would have hunted prey from the seashore, akin to a heron. A later estimate argued that the neck comprised about 30 to 43% of the body mass. Terrestrial or semi-terrestrial habits are supported by taphonomic evidence, which indicates that the preservation of Tanystropheus specimens is more similar to the terrestrial Macrocnemus than the aquatic Serpianosaurus where all three co-occur. Renesto and Franco Saller's 2018 follow-up to Renesto (2005) offered more information on the reconstructed musculature of Tanystropheus. This study determined that the first few tail vertebrae of Tanystropheus would have housed powerful tendons and ligaments that would have made the body more stiff, keeping the belly off