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.
Argentinosaurus
Not much of "Argentinosaurus" has been recovered. The holotype (specimen number, PVPH-1) included only a series of vertebrae (six from the back, five partial vertebrae from the hip region), ribs of the right side of the hip region, a part of a rib from the flank, and the right fibula (lower leg bone). One of these vertebrae was 1.59 meters tall, and the fibula was about 1.55 meters (61 inches). In addition to these bones, an incomplete femur (upper leg bone, specimen number MLP-DP 46-VIII-21-3) is assigned to "Argentinosaurus"; this incomplete femur shaft has a minimum circumference of about 1.18 meters. The completed femur is estimated at around 2.5m long. By comparison, there are complete femurs preserved in other giant titanosaurs; "Antarctosaurus giganteus" which measures 2.35m, and "Patagotitan mayorum" which measures 2.38m.