sauropods. Although Diplodocoidea and basal Macronaria also show an increase in bone growth and a decrease in growth rate around the presumed onset of sexual maturity, it is much more gradual than Ampelosaurus. The process of growing, which in other sauropods started around sexual maturity, was clearly delayed in Ampelosaurus. The period of growth after sexual maturity seems to be shortened in Ampelosaurus and is dominated by slow bone building instead of fast growth. Growth marks are generally rare in sauropods or appearing only late in ontogeny, if at all. The lack of growth marks is suggestive of fast and continuous growth in sauropods, which supports the hypothesis that they achieved large body size through because of fast growth. Ampelosaurus does not show growth marks on any bone sample. This is unusual to be found with the apparently reduced growth rate and high level of bone growth seen in it, as those features are often associated with the occurrence of growth marks. Histology EFS, a system found on the surface of bones, is thought to show a growth plateau which indicates that maximum body size and skeletal maturity is reached in an individual. Ampelosaurus has not been known to have EFS, found on most non-titanosaurian sauropods. Magyarosaurus, a closely related titanosaur, Lirainosaurus, a titanosaur related to saltasaurids, Alamosaurus, a saltasaurid, and Phuwiangosaurus, a very basal titanosaur, were also found to have lacked EFS. However, the basal macronarian Europasaurus has been shown to have had EFS, so it was likely just titanosaurians that did not have them. The outer edge of the bones, were EFS would have been found, was well-preserved, and still lacked any fossilized proof of them being present for Ampelosaurus. However, in the PLoS ONE study that found the lack of EFS, the larger specimens were not tested, so Ampelosaurus might have had EFS. This is characteristic of titanosaurs, as diplodocoids and basal macronarians seem to have EFS. A majority of all Ampelosaurus specimens have been found with secondary osteons placed densely in the inner regions of bones, and lightly in outer regions. The osteon orientation found in Ampelosaurus of osteons not only facing across the bone is not typical of Neosauropoda. Also, there is no medullary cavity in any bones of Ampelosaurus. Ampelosaurus seems to have had many ontogenetic stages in its life based on its bone histology. Paleoecology Ampelosaurus atacis is known from a specimen from