 It is likely that this undescribed leg bone belonged to the same individual animal as the neural spine, but it was never collected or described.In 2018, "A. fragillimus" was given its own genus, "Maraapunisaurus", and reclassified as a primitive rebbachisaurid.In 2010, an article was made available, but not formally published, by Henry Galiano and Raimund Albersdorfer in which they referred to the new species "A. brontodiplodocus" to "Amphicoelias", based on several complete specimens found in the Dana Quarry of Big Horn Basin, Wyoming and held in a private collection.