Largest prehistoric animals


The largest prehistoric organisms include both vertebrate and invertebrate species. Many of them are described below, along with their typical range of size. Many species mentioned might not actually be the largest representative of their clade due to the incompleteness of the fossil record and many of the sizes given are merely estimates since no complete specimen have been found. Their body mass, especially, is mostly conjecture because soft tissue was rarely fossilized. Generally the size of extinct species was subject to energetic and biomechanical constraints.

Vertebrates

Mammals (Mammalia)

Monotremes (Monotremata)

The largest cingulate known is Doedicurus, at long and reaching a mass of approximately Glyptodon easily topped and.

Hedgehogs, gymnures, shrews, and moles (Erinaceomorpha and Soricomorpha)

The largest-known animal of the Erinaceomorpha and Soricomorpha groups was Deinogalerix, measuring up to in total length, with a skull up to long.

Rabbits, hares, and pikas (Lagomorpha)

The largest-known prehistoric lagomorph is Minorcan giant lagomorph at.
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Cimolestids (Cimolesta)

The largest-known cimolestid is Coryphodon, high at the shoulder and long.

Anteaters and sloths (Pilosa)

'' skeleton

Elephants, mammoths, and mastodons (Proboscidea)

Some of the largest-known astrapotherians weighed about, including the genus Granastrapotherium and some species of Parastrapotherium. The skeleton remains suggests that the species Hilarcotherium miyou was even larger, with a weight of.

Arsinoitheres (Arsinoitheriidae)

The largest-known arsinoithere was Arsinoitherium. When alive, it would have been tall at the shoulders, and long.

Condylarths (Condylarthra)

The largest-known condylarth is Phenacodus. It was long and weighted up to.

Dinoceratans (Dinocerata)

The largest-known dinoceratan was Uintatherium. It was about the size of a rhinoceros. Despite its large size, it had a brain only about as large as an orange.

Desmostylians (Desmostylia)

The largest-known desmostylian was a species comparable in size to the Steller's Sea Cow.

Litopterns (Litopterna)

The largest-known litoptern was Macrauchenia, which had three hoofs per foot. It was a relatively large animal, with a body length of around.

Notoungulates (Notoungulata)

The largest notoungulate known of complete remains is Toxodon. It was about in body length, and about high at the shoulder and resembled a heavy rhinoceros. Although is not complete, the preserved fossils suggests that Mixotoxodon were the most massive member of the group, with a weight about.

Oxyaenids (Oxyaenidae)

The largest-known oxyaenid was Sarkastodon weighing in at.

Hyaenodontids (Hyaenodontidae)

The largest hyaenodontid was Simbakubwa at 1,500 kg.

Mesonychids (Mesonychia)

The largest mesonychid was Mongolonyx robustus. This predator would have been tall at the shoulders and long.

Non-mammal synapsids (Synapsida)

Pelycosaurs

The herbivorous Cotylorhynchus hancocki was the largest of the pelycosaurs and the largest amniote to have lived at the time, with an estimated length and weight of at least and. The biggest carnivorous pelycosaur was Dimetrodon angelensis, which could reach and. The largest members of the genus Dimetrodon was also the world's first fully terrestrial apex predators.

Therapsids

The plant-eating dicynodont Lisowicia bojani is the largest-known of all non-mammal synapsids, at and. Among the largest carnivorous synapsids was the therapsid Anteosaurus, which was long, and weighed.

Reptiles (Reptilia)

Crocodiles and relatives (Crocodylomorpha)

Plesiosauroids (Plesiosauroidea)
The longest known plesiosauroid was Styxosaurus at long. Other elasmosaurs, such as Albertonectes and Thalassomedon, rivaled the aforementioned Styxosaurus in size.
Pliosauroids (Pliosauroidea)
There is much controversy over the largest-known of the Pliosauroidea. Fossil remains of a pliosaur nicknamed as "Predator X" have been discovered and excavated from Norway in 2008. This pliosaur has been estimated at in length and in weight. However, in 2002, a team of paleontologists in Mexico discovered the remains of a pliosaur nicknamed as "Monster of Aramberri", which is also estimated at in length. This species is, however, claimed to be a juvenile and has been attacked by a larger pliosaur. Some media sources claimed that Monster of Aramberri was a Liopleurodon but its species is unconfirmed thus far.
Another very large pliosaur was Pliosaurus macromerus, known from a single incomplete mandible. It may have reached, assuming the skull was about 17% of the total body length.

Ichthyosaurs (Ichthyosauria)

The largest-known ichthyosaur was Shastasaurus sikanniensis at in length. In April 2018, paleontologists announced the discovery of a previously unknown ichthyosaur that may have reached lengths of 26 m making it one of the largest animals known, rivaling some blue whales in size. Another, larger ichthyosaur was found in 1850 in Aust, Gloucestershire, being noted in the same paper. Its remains seemed to surpass the measurements of the lilstock monster, but the researchers commented that the remains were too fragmentary for a size estimate to be made..

Turtles and tortoises (Testudines)

The heavy built Moradisaurus grandis, with a length of, is the largest known captorhinid.

Pareiasaurs (Pareiasauridae)

The largest-known pareiasaur is Scutosaurus, up to in length, with bony armor, and a number of spikes decorating its skull.

Phytosaurs (Phytosauria)

Some of the largest-known phytosaurs include Redondasaurus with a length of 6.4 meters and Smilosuchus with a size of 6.8 meters.

Pterosaurs (Pterosauria)

Sauropods (Sauropoda)

Many large sauropods are still unnamed and may rival the current record holders.
The largest-known thyreophoran was Ankylosaurus at in length and in weight. Stegosaurus was also long but around tonnes in weight.

Ceratopsians (Ceratopsia)

The largest ceratopsian known is Triceratops horridus, along with the closely related Eotriceratops xerinsularis both with estimated lengths of. Ojoceratops and several other ceratopsians rival them in size.

Ornithopods (Ornithopoda)

The very largest-known ornithopods, like Shantungosaurus were as heavy as medium-sized sauropods at up to, and in length.

Birds (Aves)

The largest-known 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 tall. The elephant birds were up to and Dromornis stirtoni was up to in weight. The tallest bird ever was the giant moa at tall.
The largest-known flight-capable bird was Argentavis magnificens with a wingspan of, and a body weight of.

Waterfowl (Anseriformes)

The largest-known waterfowl of all time belonged to the Dromornithidae.

Storks and allies (Ciconiiformes)

The largest-known of Ciconiiformes was Leptoptilos robustus, standing tall and weighing an estimated.

Hesperornithines (Hesperornithes)

The largest-known of the hesperornithines was Canadaga arctica at long.

Gastornid (Gastornithiformes)

Individuals of Gastornis averaged in height, with large individuals up to tall.

Teratorns (Teratornithidae)

The largest-known teratorn and the largest flying bird ever was Argentavis. The immense bird had a wingspan estimated up to and a weight up to. It was as high as an adult human when standing.

Phorusrhacids (Phorusrhacidae)

The largest-known-ever gruiform and largest phorusrhacid or "terror bird" was Brontornis, which was about tall at the shoulder, could raise its head above the ground and could have weighed as much as. The immense phorusrhacid Kelenken stood tall with a skull long, had the largest head of any known bird. The largest North American phorusrhacid is Titanis, which is about tall, as tall as a forest elephant.

Accipitriforms (Accipitriformes)

The largest-known bird of prey ever was the enormous Haast's eagle, with a wingspan of, relatively short for their size. Total length was probably up to in female and they weighed about. The largest extinct Titanohierax was a giant hawk about 8 kilograms that lived in the Antilles, where it was among the top predators.
, the largest bird of prey, attacking moa

Gamebirds (Galliformes)

The largest-known of the Galliformes was a giant flightless Sylviornis, a bird long and weighing up to about.

Songbirds (Passeriformes)

The largest-known songbird is the extinct giant grosbeak at long.

Cormorants and allies (Pelecaniformes)

The largest-known cormorant was the spectacled cormorant of the North Pacific, which became extinct around 1850, was larger still, averaging around and.

Bony-toothed birds (Odontopterygiformes)

The largest-known of the Odontopterygiformes—a group which has been variously allied with Procellariiformes, Pelecaniformes and Anseriformes—and the largest flying birds of all time other than Argentavis were the huge Pelagornis, Cyphornis, Dasornis, Gigantornis and Osteodontornis. They had a wingspan of and stood about tall. Exact size estimates and judging which one was largest are not yet possible for these birds, as their bones were extremely thin-walled, light and fragile, and thus most are only known from very incomplete remains.

Woodpeckers and allies (Piciformes)

The largest-known woodpecker is the possibly extinct imperial woodpecker with a total length of about. The largest woodpecker confirmed to be extant is the great slaty woodpecker.

Parrots (Psittaciformes)

The largest-known parrot is the extinct heracles inexpectatus about 1 meter long.

Penguins (Sphenisciformes)

The largest-known penguin of all time was Anthropornis nordenskjoeldi of New Zealand and Antarctica. It stood in height and was in weight. Similar in size were the New Zealand giant penguin with a height of and weighing possibly around and over, and Icadyptes salasi at tall.

Owls (Strigiformes)

The largest-known owl of all time was the Cuban Ornimegalonyx at tall probably exceeding.

Amphibians (Amphibia)

The largest-known amphibian of all time was the long temnospondyli Prionosuchus.
Another huge temnospondyli was Koolasuchus at long, but only high.

Frogs (Anura)

The largest-known frog ever was an as yet unnamed species that was about.

Diadectomorpha

The largest-known diacectid, Diadectes, was a heavily built animal, long, with thick vertebrae and ribs.

Anthracosauria

The largest-known anthracosaur was Anthracosaurus, a predator. It could reach up to in length. Eogyrinus commonly reached ; however, it was more lightly built.

Temnospondyli

The largest-known temnospondyl amphibian is Prionosuchus, which grew to lengths of.

Lobe-finned fish (Sarcopterygii)

The largest-known lobe-finned fish was the long Rhizodus.

Ray-finned fish (Actinopterygii)

The largest-known ray-finned fish and largest bony fish of all time was the pachycormid, Leedsichthys problematicus, at around long. Claims of larger individuals persist.

Ichthyodectiformes (Ichthyodectiformes)

The largest-known of ichthyodectiform fish was Xiphactinus, which measured long.

Cartilaginous fish (Chondrichthyes)

Mackerel sharks (Lamniformes)

An extinct megatoothed shark, C. megalodon is by far the biggest mackerel shark and largest shark known. This giant shark reached a total length of more than. C. megalodon may have approached a maximum of in total length and in mass.

Symmoriid (Symmoriida)

The largest-known symmoriid was Stethacanthus at long.

Eugenedont (Eugeneodontida)

The largest-known eugenedont is an as-yet unnamed species of Helicoprion discovered in Idaho. The specimens suggest an animal that possibly exceeded in length.
Another fairly large eugenedont is Parahelicoprion. The specimens suggest an animal that grew to the same size, but was much more slender and overall less heavy.

Hybodontiform (Hybodontiformes)

The largest-known hydontiformid is Ptychodus, which was about long.

Placoderms (Placodermi)

The largest-known placoderm was the long Dunkleosteus. It is estimated to have weighed around. Its relative, Titanichthys, may have rivaled it in size.

Arthropods ([Arthropoda])

[Dinocaridida]

Radiodont ([Radiodonta])

The largest-known is Aegirocassis at least long.

[Chelicerata]

Eurypterids ([Eurypterida])

The largest-known in this group was Jaekelopterus rhenaniae at in length. A close contender was Pterygotus at in length.

Arachnids ([Arachnida])

There are two contenders for largest-known ever arachnid: Pulmonoscorpius kirktonensis and Brontoscorpio anglicus. Pulmonoscorpius was Brontoscorpio was. The biggest difference is that Brontoscorpio was aquatic, and Pulmonoscorpius was terrestrial. Brontoscorpio is not to be confused with various Eurypterids: it was a true scorpion with a venomous stinger.

[Myriapoda]

The largest-known myriapod by far was the giant Arthropleura. Measuring and wide, it was the largest-known terrestrial arthropod of all time. Like its modern-day relatives, Arthropleura would have likely sprayed hydrogen cyanide at potential predators, although its sheer size and tough exoskeleton protected it from attack.

Trilobitomorpha

Trilobites ([Trilobita])

Some of these extinct marine arthropods exceeded in length. A nearly complete specimen of Isotelus rex from Manitoba attained a length over, and an Ogyginus forteyi from Portugal was almost as long. Fragments of trilobites suggest even larger record sizes. An isolated pygidium of Hungioides bohemicus implies that the full animal was long.

Insects ([Insecta])

Sawflies, wasps, bees, ants and allies ([Hymenoptera])

The largest-known of this group was the giant ant Titanomyrma giganteum at, with queens growing to. It had a wingspan of.

Protodonata

The largest-known in this group was probably Meganeura with a wingspan of. Another enormous and possibly larger species was Meganeuropsis permiana.

Siphonaptera

The largest-known in this group was probably Saurophthirus, growing to in length. It possibly sucked the blood of pterosaurs.

Palaeodictyoptera

The largest-known insect of this order was Mazothairos, with a wingspan of up to.

Molluscs ([Mollusca])

Gastropods ([Gastropoda])

Snails and slugs ([Gastropoda])

The largest-known of this group were in the genus Campanile, with the extinct Campanile giganteum having shell lengths up to.

Bivalves ([Bivalvia])

Bivalves ([Bivalvia])

The largest-known bivalve ever was Platyceramus platinus, a giant that usually had an axial length of, but some individuals could reach an axial length of up to.

Cephalopods ([Cephalopoda])

Ammonites ([Ammonoidea])

The largest-known ammonite was Parapuzosia seppenradensis. A partial fossil specimen found in Germany had a shell diameter of, but the living chamber was incomplete, so the estimated shell diameter was probably about when it was alive.

Belemnites ([Belemnoidea])

The largest-known belemnite was Megateuthis gigantea with a guard of in length and an estimated total length long.

Nautiloids ([Nautiloidea])

The longest- and largest-known of this group was Cameroceras with a shell length of.

Neocoleoidea

Both Tusoteuthis and Yezoteuthis are estimated to be similar in size to the modern-day giant squid.