What Was the Biggest Dinosaur ? | Mesozo


One of the most exciting aspects and characteristics of dinosaurs is that they had big sized bodies. This animal shows different variations in the size of their bodies, having the carnivorous and herbivorous type of dinosaurs. Dinosaurs existed during various periods up to their extinction. There is evidence of this existence since their fossils have already been discovered. Scientists, however, have no specific answer to what was the most significant or smallest dinosaur that ever existed. However, Some dinosaurs whose fossils have already been discovered can clearly show evidence of their massive bodies during their existence.

Moreover, few of these fossils of specimens are found incomplete skeleton structure, and impressions of soft tissue and skin are very rare. Some of the biggest dinosaurs that ever existed on the planet include the Titanosaurian Sauropod dinosaurs. They were the most abundant large-sized herbivores that ever existed in the southern hemisphere and across the world. The biggest dinosaurs that ever lived include;


Argentinosaurus was discovered in Argentina in 1987; this is the world's most giant dinosaur. Since the discovery of this Dinosaur, Paleontologists have argued on its weight and length. Argentinosaurus is a dinosaur of the sauropod genus, and it existed during the late Cretaceous period. Its length ranges from 30 to 40 meters and weighed about 50 to 100 tonnes. Going by these measures, Argentinosaurus is one of the biggest and most massive land animals ever known. This dinosaur among the dominant group of sauropods since it was a member of Titanosauria in the Cretaceous period.

Argentinosaurus bone was first discovered in 1987, and it was thought to be a calf bone. Argentinosaurus was also quadrupedal, had grinding teeth, and is believed to be a herbivore. Fossilized remains are evidence that it also laid thousands of eggs within a 15 km nesting site that could be used for hundreds of thousand years. Sixty-five million years ago, this type of dinosaurs became extinct after living on the planet for more than 165 million years.



Dreadnoughtus is a titanosaurian sauropod genus dinosaur that contains a single species. This dinosaur is one of the biggest of all the known terrestrial vertebrates. It possesses the mass that no land animal has ever recorded. Based on its skeleton, Dreadnoughtus had an approximate length of 26 meters and about 6 meters in height. Its tail was about 8.7 meters long, with 11.3 necks long. Kenneth Lacovara, a paleontologist from Drexel University, discovered the species and named them Dreadnoughtus, meaning fears nothing.

Its discovery enabled insight into the size and anatomy of giant titanosaurian dinosaurs, especially the shoulders, hip girdles, and limbs. Most of the Dreadnoughtus bones are highly preserved for scientific use. The location of muscle attachment features is seen. This dinosaur had a long neck such that it consisted of half the length of this animal. Its estimated weight ranged from about 22 to 38 tonnes.



Scientific study shows that Patagotitan Mayorum was the most massive dinosaur that ever lived, making T-Rex look so small compared to its size. It was as heavy as a shuttle from space since this herbivore could weigh up to 76 tons. Patagotitan Mayorum fossils were first discovered in 2012 in southern Argentina. Researchers named this dinosaur as Patagotitan Mayorum since the fossils were found in the Patagonian region and titan, meaning large. There were six fossils of Patagotitan that were studied and date back to around 100 million years ago. At the American Museum of Natural History, there is a cast of Patagotitan skeleton displayed.

According to the height of this dinosaur, carnivorous dinosaurs like the mighty Tyrannosaurus Rex looks like dwarfs around this type of dinosaur. Patagotitan was like other titanosaurs with a long neck, long tail, large body size, and also quadrupedal. Based on the research and scientific study of its fossils, Patagotitan measurements are comparable to other giant titanosaurs.

 Patagotitan biggest dinosaur


This type of a dinosaur is of genus titanosaurian sauropod dinosaur that existed in the late cretaceous period. Dr. Bernardo Javier González Riga, an Argentine paleontologist, discovered the fossils of a giant Sauropod in Mendoza province. Evidence and study show that this dinosaur was among the most extensive and heaviest titanosaurs that ever lived. Notocolossus may have weighed around 44 to 76 tonnes, and most probably, many of this species weighed 60 tonnes. Estimates from the remains of its upper bone show that Notocolossus may have been longer than other titanosaurs like Dreadnoughtus.

 Notocolossus biggest dinosaur


Alamosaurus is also from the genus of titanosaurian sauropod dinosaurs, and it has only one known species of Alamosaurus Sanjuanensis of the late cretaceous period. Its fossils have been found in places such as Coahuila (Mexico), New Mexico, and Utah. Its size is comparable to Argentinousarus from the evidence of the limb bones, and isolated vertebrae remain. It was a big herbivore and had a long neck, tail, and limbs. Moreover, this dinosaur was quadrupedal, and its estimated length was about 30 meters. Though the evidence and the remains of Alamosaurus are that of juvenile or small adults, the study of this remains shows that Alamosaurus could have grown so significant to a weight of around 73 metric tons. Thirty different specimens have been collected and found, and they show that Alamosaurus reproduced by laying eggs and lived in terrestrial habitats.
Therefore the fossils of Alamosaurus and study clearly show that it was one of the biggest dinosaurs that ever existed on the planet.

   Alamosaurus biggest dinosaur

Illustration of a herd of Alamosaurus


Giganotosaurus roamed in modern-day Argentina in the late Cretaceous period. This giant fresh eating dinosaur lived about 99.6 to 97 million years ago. It is believed to have been much bigger than the Tyrannosaurus Rex but ranked number two in terms of the most abundant carnivore dinosaur that ever lived. Giganotosaurus weighed about 14 tons and 40 to 45 feet long body. It was of theropod genus, and its holo-type specimen was first discovered in Patagonia in 1993.

This dinosaur was named Giganotosaurus, meaning giant southern lizard. The estimates of its size are done from its specimen range of 12 to 13 meters in length, 1.5 to 1.8 meters skull, and a weight of around 4.3 to 13.8 tonnes. The study and model suggest that Giganotosaurus could even reach a speed of 50 kilometers per hour. This dinosaur walked upright using its bipedal legs, which were very powerful. Its balance was brought about by the thin pointed tail and could quickly turn while running.

 Giganotosaurus biggest dinosaur


Diplodocus is the only longest dinosaur with a complete skeleton of its remains; other dinosaurs had incomplete skeletons; hence their size was based on estimates of this fragmentary remains. Diplodocus was one of the longest dinosaurs that ever walked planet earth. This was brought about by its unique body formation, which consisted of 2 rows of bones on the underside of its tail that provided excellent mobility and extra support. Because of this unusual body physical structure paleontologist, Othniel Marsh derived its name from a Greek word diplos that meant double and dokos meaning beam. This dinosaur was a herbivorous sauropod with a long neck. Diplodocus lived about 155.7 million years ago during the late Jurassic period.

Some of the length taken and studied on its fossils suggest that diplodocus was at least 6.5 meters long. Its first fossils were found in 1877 by Benjamin Mudge and Samuel Williston next to Canon City and were named by paleontologist Marsh in 1878. After that, more fossils have been discovered in Montana, Utah, Rocky Mountain region of Colorado and Wyoming.

Diplodocus biggest dinosaur

Barosaurus was a gigantic long-tailed, long-necked, and herbivorous dinosaur that had a close relationship with the Diplodocus family. Barosaurus was a long dinosaur; some of the full-grown adults could grow up to 26 meters in length. While adults could weigh 20 metric tonnes, there are indications that some could also grow up to 50 meters in length and carry a weight of 100 tonnes. This dinosaur was quadrupedal like diplodocus. Scientists are yet to find its skull. Some of its remains have been found in Utah and South Dakota. Its name "Barosaurus" means massive lizard, and it existed during the upper Jurassic period about 161 to 145 million years ago. Most of its real complete skeleton is on display in Royal Ontario Museum in Toronto, Canada. These remains of Barosaurus were found in Carnegie Quarry.

Barosaurus biggest dnosaur


Brachiosaurus was a giraffe-like a dinosaur that lived around 155.7 to 150.8 million years ago in the middle of the late Jurassic period. Its fossils and remains were found in the abundant mineral Morrison Formation of North America. Brachiosaurus was unique and did not look like other dinosaurs that roamed North America. This dinosaur had longer front legs compared to its hind legs; hence its name "arm lizard," it also had a long neck making it resemble a giraffe. Although it was unclear how large Brachiosaurus, the estimates were based on the African form fossils.

Paleontologist Taylor later did assessments using the North American Species. The paleontologist estimated the length of Brachiosaurus to be about 25 meters long though this dinosaur could be even more massive since the fossils were not fully grown yet. Moreover, according to recent studies, the dinosaur is estimated to have weighed about 56 metric tons. Brachiosaurus was said to be the giant dinosaur to ever exist at the time of its discovery, but a recent study shows Sauropods may have been more massive.

Brachiosaurus biggest dinosaur  

Paralititan is one of the biggest sauropod dinosaurs to ever exist without no doubt. However, the remains and skeleton of Paralititan are incomplete. Still, its upper bone is said to have been 169 centimeters long, which is one of the longest numerous bone ever known by man throughout dinosaur history. Kenneth Carpenter, a paleontologist in 2006, estimated Paralititan to be about 26 meters long. Paralititan was a large Sauropod dinosaur genus that lived approximately 99.6 to 93.5 million years ago in the Upper Cretaceous Bahariya Formation of Egypt. Some of the comparable dinosaurs to Paralititan in terms of physical size are sauropods like Dreadnoughtus and Argentinosaurus.

This dinosaur was quadrupedal, its fossils that were discovered in Bahariya formation consists of a partial skeleton without a skull. The specimen of v shows that despite its massive body, this dinosaur was under constant attacks by the carnivorous dinosaur that is said to be a Carcharodontosaurus dinosaur. 

Paralititan biggest dinosaur

Camarasaurus is a sauropod dinosaur that lived about 161 to 146 million years ago during the late Jurassic period. Its name, Camarasaurus, means chambered lizard, and it is believed to have lived in herds. The fossils of Camarasaurus were found in western North America. Although these dinosaurs were smaller than other sauropods like Brachiosaurus and diplodocids, it could grow up to a length of 18 meters. It had long tail and neck, large-spooned shaped teeth, and snub-nosed skulls.

Camarasaurus was a quadrupedal herbivore that was most common among the sauropod dinosaurs in North America. Its fossils dating back to the late Jurassic epoch were found in Utah and the Morrison Formation of Colorado. This sauropod dinosaur was about 7.5 to 20 meters in length according to estimates done by paleontologist and could weigh more than 20000 kilograms. 

Camarasaurus biggest dinosaur


 Sauroposeidon is of the family of sauropod dinosaurs and is known to be the tallest dinosaur among the sauropods and all dinosaurs. Sauroposeidon dinosaur lived about 125 to 100 million years ago in the Aptian-Albian. Sauroposeidon fossils were discovered in South Eastern Oklahoma with only four neck vertebrae in the early cretaceous period. It was until 1999 that their true nature and characteristics were revealed since they had been misclassified as tree trucks back in 1993. It was of the species of brachiosaurids. This dinosaur was a quadrupedal herbivorous dinosaur with front legs been longer.

According to paleontologists, Sauroposeidon resided on the shore of the Gulf of Mexico, which stretched up to Oklahoma. The estimated length of this sauropod dinosaur is up to 34 meters in length and could weight 50 to 60 tonnes. Sauroposeidon could reach a height of 18 meters with its neck extended hence ranking the tallest and heaviest dinosaur ever to exist. Although Sauroposeidon and other dinosaurs researched did not exist during the same period, they were the biggest dinosaurs to ever exist on planet earth.

Sauroposeidon biggest dinosaur

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