Largest extinct animals

The largest extinct animals known to date are listed here. They are arranged by their taxonomy (classification). The list only deals with individual animals; size of colonies (such as coral reefs) is not dealt with here.
Vertebrates.
Fish.
The largest bony fish of all time was "Leedsichthys problematicus" from the Middle Jurassic, at around long. Earlier claims have been scaled down.
The extinct megatoothed shark, "C. megalodon" is by far the biggest and most powerful shark that ever lived. This giant shark reached a length of more than . Recent higher estimates place the largest individuals of Megalodon at 20.3 meters (66 ft), making it the largest fish of all time.
Reptiles.
Turtles.
The largest fossil turtle seems to be the freshwater turtle "Stupendemys", with an estimated total carapace length of more than 11 feet (3.3 metres). A close contender is "Archelon ischyros", a sea turtle, which reached a length of 16 feet (4.8 m) across the flippers and a weight of over 4,850 lb (2,200 kg). For comparison, the largest living turtle is the Leatherback Sea Turtle at a maximum 2000 lbs (900 kg).
Archosaurs.
While often suggested to be the largest crocodilian, "Sarcosuchus imperator" has been recently cut down to 4 tonnes in weight and 9 meters in length. "Deinosuchus", estimated at around , is a strong contender for the title.
Pterosaurs.
The largest pterosaur was "Quetzalcoatlus northropi", at 127 kg (280 lbs) and with a wingspan of 11 m (36 ft). Another close contender is "Hatzegopteryx", also with a wingspan of 11 m (this estimate is based on a skull 3 m long (10 ft).
Dinosaurs.
Titanosaurs hold the world record for the size of a land animal. A recent discovery in the Argentine found "Dreadnoughtus", an estimated length of 26 metres (85 feet) and weight of 59,291 kg (65.4 short tons). Its bones showed it was a sub-adult.
A notably large titanosaurid is "Argentinosaurus", which is known from partially preserved remains. This sauropod has been estimated as long and 73–99 metric tons in weight. The lack of skeletal material makes these estimates uncertain.
The very largest ornithopods, like "Shantungosaurus" were as heavy as medium-sized sauropods at up to 23 metric tons "Lambeosaurus laticaudus" appears to be close contender at around in length.
The largest known theropod is "Spinosaurus aegyptiacus", estimated at in length and around 7–9 metric tons in weight. "Spinosaurus aegyptiacus" is also recognized as the largest terrestrial predator yet known.
A close contender in size is a giant theropod from South America, "Giganotosaurus carolinii", whose holotype specimen is estimated at in length, and another specimen is estimated at in length. A study however presents "Carcharodontosaurus" as a close contender in size to "Spinosaurus aegyptiacus". Some other notable giant theropods (e.g. "Tyrannosaurus rex", "Acrocanthosaurus", and "") may also have rivaled these giant theropods in size. Another very large theropod was "Deinocheirus", being tall at hips,
and weighing up to 16,000 pounds. The largest dromaeosaurid is "Utahraptor". In addition to being the largest known dromaeosaurid, it was also the largest known deinonychosaur and the largest known paravian.
The largest thyreophoran was "Ankylosaurus" at in length and 6.5 tons in weight. "Stegosaurus" was also 9 meters (30 ft) long but around 5 tons in weight.
The largest ceratopsian known is probably the newly discovered "Eotriceratops" with a skull alone being in length. Maximum size of this ceratopsian is suggested to be around in length and 13 tonnes in weight.
Ichthyosaurs.
The largest ichthyosaur was "Shonisaurus sikanniensis" at ~21 metres (70 ft) in length. This would make it the largest extinct marine animal.
Plesiosaurs.
The largest plesiosaur was "Mauisaurus haasti", growing to about 20 metres (66 ft) in length. Next behind was "Elasmosaurus" at 14 metres (46 ft) long.
There is much controversy here. Fossil remains of a pliosaur nicknamed "Predator X" were excavated from Norway in 2008. It was about in length and 41 metric tons in weight. However, in 2002, a team of paleontologists in Mexico discovered the remains of a pliosaur "Monster of Aramberri", which is also estimated at in length. However, this specimen is thought to be a juvenile, with evidence that it had been attacked by an even larger pliosaur. Some media claimed that "Monster of Aramberri" was a "Liopleurodon" this is unconfirmed.
Squamata.
The largest known prehistoric snake is "Titanoboa", estimated at in length and 1135 kg–1819 kg in weight. Another large fossil snake is ', estimated at around in length. Both these snakes lived in tropical rain forests. In third place is an aquatic snake, ', which may have been around in length.
Giant mosasaurs are the largest animals in the Squamata. The largest known mosasaur is likely "Mosasaurus hoffmanni", estimated at least in length. A close contender in size is "Hainosaurus bernardi", estimated at in length. Another giant mosasaur is "Tylosaurus", estimated at in length.
Birds.
The largest birds of all time might have been the elephant birds of Madagascar. Of almost the same size was the Australian "Dromornis stirtoni". Both were about 3 m tall (10 ft). The elephant birds were up to 400 kg and "Dromornis" was up to 500 kg in weight. The tallest bird ever was the Giant Moa ("Dinornis maximus") at 12 ft tall.
The largest flight-capable bird was "Argentavis magnificens" which had a wingspan of 7 m (~23 ft), and a body weight of 110 kg (244 lb), or "Pelagornis sandersi" with a wingspan of 6.4 to 7.4 metres.
Mammals.
Whales.
"Basilosaurus" was once recognized as one of the largest known extinct cetaceans at in length.
The largest fossil toothed whale was the Miocene whale "Livyatan melvillei" which was estimated to be in length. One notable feature of "L. melvillei" was its teeth which were 36 cm long and is unmatched by any other animal, extinct or alive.
However, the largest fossil whales were baleen whales (plankton feeders) from the Pliocene and Pleistocene Epochs. A notable example is the bones of a Pliocene age baleen whale, assigned the questionable name "Balaenoptera sibbaldina", which likely rivaled the modern blue whale in size.
Land mammals.
The largest perissodactyl, and land mammal, of all time was "Palaeoloxodon namadicus". It stood 5.5 m (18 ft) tall at the shoulder, with a total height of 8 m (27 ft). It was 12 m (40 ft) long and may have weighed 20 tonnes (22 tons), though mass estimates vary. Some prehistoric horned rhinos also grew to large sizes. The giant woolly rhino "Elasmotherium" reached 20 ft long and 6.6 ft high.
Invertebrates.
Myriapoda.
Millipedes (Diplopoda).
The largest by far was the giant "Arthropleura". Measuring 2.5 metres (8.2 ft) and 45 centimetres (18 in) wide, it was the largest terrestrial arthropod of all time.