Sue (dinosaur)
Sue is the nickname given to FMNH PR 2081, which is the largest, most extensive and best preserved "Tyrannosaurus rex" specimen ever found, at over 90% recovered by bulk. It was discovered in August 1990, by Sue Hendrickson, an explorer and fossil collector, and was named after her. After ownership disputes were settled, the fossil was auctioned in October 1997, for US $8.3 million, the highest amount ever paid for a dinosaur fossil, and is now a permanent feature at the Field Museum of Natural History in Chicago, Illinois.
Megafauna
Since tetrapods (first reptiles, later mammals) returned to the sea in the Late Permian, they have dominated the top end of the marine body size range, due to the more efficient intake of oxygen possible using lungs. The ancestors of cetaceans are believed to have been the semiaquatic pakicetids, no larger than wolves, of about 53 million years (Ma) ago. By 40 Ma ago, cetaceans had attained a length of 20 m or more in "Basilosaurus", an elongated, serpentine whale that differed from modern whales in many respects and was not ancestral to them. Following this, the evolution of large body size in cetaceans appears to have come to a temporary halt, and then to have backtracked, although the available fossil records are limited. However, in the period from 31 Ma ago (in the Oligocene) to the present, cetaceans underwent a significantly more rapid sustained increase in body mass (a rate of increase in "body mass" of a factor of 3.2 per million years) than achieved by any group of terrestrial mammals. This trend led to the largest animal of all time, the modern blue whale. Several reasons for the more rapid evolution of large body size in cetaceans are possible. Fewer biomechanical constraints on increases in body size may be associated with suspension in water as opposed to standing against the force of gravity, and with swimming movements as opposed to terrestrial locomotion. Also, the greater heat capacity and thermal conductivity of water compared to air may increase the thermoregulatory advantage of large body size in marine endotherms, although diminishing returns apply.