Dinosaur size
[2] Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100–1,000 kg (220–2,200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the range of 10–100 kg (22–220 lb).
[4] This contrasts sharply with the size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb).
Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better-known species is an inexact art (though governed by some established allometric trends), and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork, and never perfect.
Analysis of the illustrations included in the original report suggested that M. fragillimus may have been the largest land animal of all time, possibly weighing 100–150 t (110–170 short tons) and measuring between 40–60 m (130–200 ft) long.
The study, however, also reclassified the species and correspondingly gave a much lower length estimate of 30.3 metres (99 ft) and a mass of 78.5 t (86.5 short tons).
[11] This in itself would later be disputed as being too small for an animal of such size, with some believing it to be even larger at around 35–40 metres (115–131 ft) and weighing around 80–120 t (88–132 short tons).
[12] Another large but even more controversial sauropod is Bruhathkayosaurus, which had a calculated weight ranging between 126–220 t (139–243 short tons) and a length of 44.1 m (145 ft)[13][14][15] Although the existence of this sauropod had long been dismissed as a potential fake or a misidentification of a petrified tree trunk, recent photographic evidence emerged, confirming its existence.
According to Gregory S. Paul, 'super-sauropods' or 'land-whales' such as Maraapunisaurus, Bruhathkayosaurus and the "Broome Titanosaur footprints," as he calls them, should not be surprising as sauropods were more heat tolerant and grew rapidly, which allowed them to reach truly titanic sizes that rivaled the largest whales in mass despite the prevalence of air sacs.
[17] Other potential factors for such extreme sauropod sizes include increasing bone robustness and load-distributing cartilaginous features to better redistribute and support such massive weights.
For much of the dinosaur era, the smallest sauropods were larger than almost anything else in their habitat, and the largest were an order of magnitude more massive than anything else known to have walked the Earth since.
One of the longest complete dinosaurs is the 27-metre-long (89 ft) Diplodocus, which was discovered in Wyoming in the United States and displayed in Pittsburgh's Carnegie Natural History Museum in 1907.
[29] The titanosaur, named Patagotitan mayorum, was estimated to have been around 40 m (130 ft) long weighing around 77 t (85 short tons), larger than any other previously found sauropod.
[38] The smallest dinosaur known from adult specimens which is definitely not an avialan is Parvicursor remotus, at 162 grams (5.7 oz) and measuring 39 centimetres (15 in) long.
