Nopcsaspondylus

Nopcsaspondylus (meaning "Nopcsa's vertebra", in reference to the original describer) is a dubious genus of rebbachisaurid sauropod dinosaur from the Cenomanian-aged (Upper Cretaceous) Candeleros Formation of Neuquén, Argentina. It is based on a now-lost back vertebra described by Nopcsa in 1902 but not named at the time. The specimen had a small vertebral body and large hollows, now known to be typical of rebbachisaurids.

==History of research== thumb|left|Skeletal diagram showing the now lost vertebra The only known specimen of Nopcsaspondylus is a fossilized dorsal vertebra collected in 1889 by Slovenian researcher Hugo Zapałowicz and transferred to the geological collection of the University of Vienna. The first person known to study the specimen, Hungarian paleontologist Franz Nopcsa von Felső-Szilvás, described it in a 1902 publication and recognized it as belonging to a sauropod dinosaur, assigning it to the genus Bothriospondylus. According to Nopcsa, the label on the fossil stated that it was collected on the left bank of the Limay River in Argentina, about 80 kilometers south of the confluence of the Limay and Neuquén rivers. A year later, American paleontologist John Bell Hatcher claimed that this vertebra was indistinguishable from those of Haplocanthosaurus, a sauropod known from Colorado, and that while the Argentine vertebra does not undoubtedly represent the same genus as the Colorado material, the two are very similar in structure. The vertebra would next be studied by German paleontologist Friedrich von Huene, who wrote a monograph published in 1929 in which he reassigns the material to the species Titanosaurus australis, and the locality from which it originates is named as Alarcón for the first time.