Alamosaurus
Alamosaurus (; meaning "Ojo Alamo lizard") is a genus of titanosaurian sauropod dinosaurs, containing a single known species, Alamosaurus sanjuanensis, from the late Cretaceous Period of what is now southern North America. Isolated vertebrae and limb bones indicate that it reached sizes comparable to "Argentinosaurus" and "Puertasaurus", which would make it the largest dinosaur known from North America. Its fossils have been recovered from a variety of rock formations spanning the Maastrichtian age of the late Cretaceous period. Specimens of a juvenile "Alamosaurus sanjuanensis" have been recovered from only a few meters below the Cretaceous-Paleogene boundary in Texas, making it among the last surviving non-avian dinosaur species.
Puertasaurus
Due to a lack of better material, the size of "Puertasaurus" is difficult to estimate. Novas estimated the new species was approximately long and weighing between . This would place it as one of the largest dinosaurs, only rivaled in size by its relative "Argentinosaurus", which has been estimated at up to in length and in mass. The discovery of the more complete "Futalognkosaurus" revealed these previous estimates were likely too high. In 2012, Thomas Holtz estimated "Puertasaurus" to have been potentially long. In 2013, the entire neck was estimated to have been approximately long by Mike Taylor and Matt Wedel. Later the same year, Scott Hartman made a reconstruction that suggests a total length of , slightly shorter than other estimates. In 2016, Gregory S. Paul estimated a length of and a weight of at least . In 2017, paleontologist José Carballido and his colleagues estimated its mass at roughly , which was lighter than "Patagotitan", a more complete giant sauropod.