derived from the Greek αμπελος, "the vine" and the Latinised Greek saurus, "reptile". Therefore, Ampelosaurus means "vineyard lizard" after the Blanquette de Limoux vineyard. The vineyard is located on the south side of the region Ampelosaurus was found in. The specific name is based on the Latin atax, the "Aude river". The first remains were found in a bonebed discovered in 1989, which produced numerous ribs and vertebrae from the back and tail, as well as many limb bones, but no skull material aside from one tooth. Four osteoderms of different sizes and shapes were also recovered from this bonebed. This material comes from several different individuals. Since 1989, more material has been uncovered in the same region of France, including a relatively complete skeleton with some elements of the skull and lower jaw. Later, in 2001, the Campagne-sur-Aude site was explored again, this time by Gerard Chauvet, Jean-Luc Le Douarec, Colette Rives and Yvonne Vidoux. After 13 years of searching, they had uncovered a mostly complete skeleton that contained much more material, including bones unknown from the holotype. The material all went to the Musee des Dinosaures, and together took about 10 years to assemble. The A. sp. was discovered in 2007. It was found in the course of the construction of a high-speed rail track connecting Madrid with Valencia, in a fossil site that many animals were found in, in the Villalba de la Sierra Formation. The site was at a locality named “Lo Hueco,” near the village of Fuentes, Castile-La Mancha, Spain. Over the course of several months, a large-scale emergency excavation by over 60 paleontologists and 100 manual workers allowed thousands of specimens of plants, invertebrates, and vertebrates of late Campanian-early Maastrichtian age to be saved, including A. sp. Ampelosaurus sp. A fossil braincase from Lo Hueco was tentatively assigned to an unnamed species of Ampelosaurus, A. sp., in a 2013 article in the journal PLoS ONE. The braincase was found to share many features with A. atacis, such as a back of the skull that is flat. The braincase, MCCM-HUE-8741, is small in size overall, with a front-to-back length of , and the maximum width of the left half being . Parts of the bottom half of the braincase are missing. Even though section are missing, the specimen does not appear to have been deformed much, as the left and right halves are not very