Brontosaurus
"Brontosaurus" was a large, long-necked quadrupedal animal with a long, whip-like tail, and forelimbs that were slightly shorter than its hindlimbs. The largest species, "B. excelsus", weighed up to and measured up to long from head to tail. For comparison, the current largest land animal, the average male African bush elephant is 3.20 m (10.5 ft) tall at the shoulder and has a body mass of 6,000 kg (13,228 lb) or 6.6 short tons.
Maraapunisaurus
In 1994, using the related "Diplodocus" as a reference, Gregory S. Paul estimated a femur length of for "A. fragillimus". The 2006 re-evaluation of "A. fragillimus" by Carpenter also used "Diplodocus" as a scale guide, finding a femur height of . Carpenter went on to estimate the complete size of "M. fragillimus", though he cautioned that relative proportions in diplodocids could vary from species to species. Assuming the same proportions as the well-known "Diplodocus", Carpenter presented an estimated total length of , which he noted fell within the range presented by Paul in 1994 (). Carpenter pointed out that even the lowest length estimates for "A. fragillimus" were higher than those for other giant sauropods, such as the diplodocid "Supersaurus" (), the brachiosaurid "Sauroposeidon" (), and the titanosaur "Argentinosaurus" (). Carpenter presented more speculative, specific proportions for "M. fragillimus" (again, based on a scaled-up "Diplodocus"), including a neck length of , a body length of , and a tail length of . He estimated the total forelimb height at and hind limb height at , and the overall height (at the highest point on the back) at . By comparison, the blue whale reaches in length.