Scientific Repository

Dinos101

Explore each species discovered by paleontology: where it lived, which bones were found, and how our understanding evolved over time.

101

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Brazilian species

Filter by: 101 species

AR · 83–80 Ma

Abelisaurus comahuensis

"Abel's lizard from the Comahue region"

Abelisaurus comahuensis is the dinosaur that gave its name to the entire Abelisauridae family, one of the most successful predator groups of Gondwana. It lived during the Campanian stage of the Late Cretaceous, approximately 83 to 80 million years ago, in what is now Patagonia, Argentina. Known from a single partial skull discovered in 1983, it was a medium-sized bipedal theropod roughly 7.4 meters long and weighing about 1.5 metric tons. The skull, estimated at over 85 centimeters long, bears characteristic rough ridges and large fenestrae that reduced skull weight. Its more derived relatives, such as Carnotaurus and Majungasaurus, became far more famous, but it was Abelisaurus that opened the way for recognition of the entire lineage.

Cretáceous Carnivore 7.4m

US · 125–110 Ma

Acrocanthosaurus atokensis

"High-spined lizard from Atoka"

Acrocanthosaurus atokensis was the largest terrestrial predator of Early Cretaceous North America. Measuring around 11 to 12 meters long and weighing up to 6 metric tons, it was distinguished by tall neural spines running along its back, forming a prominent muscular ridge. Its long, narrow skull housed recurved serrated teeth, and its forelimbs, though robust, had limited range of motion. It lived approximately 113 to 110 million years ago on the coastal plains of what is now the southern and central United States, hunting large sauropods and ornithopods. Its giant trackways preserved in Texas are direct evidence of its dominant presence.

Cretáceous Carnivore 11.5m

CA · 70–68 Ma

Albertosaurus sarcophagus

"Flesh-eating lizard of Alberta"

Albertosaurus sarcophagus was a medium-sized tyrannosaurid that lived during the late Campanian, 70 to 68 million years ago, in what is now the Canadian province of Alberta. At around 8 to 9 meters long and between 1,300 and 1,700 kg, it was smaller and more agile than its later relative Tyrannosaurus rex. It is distinguished by a relatively narrower skull, proportionally longer hindlimbs, and an estimated locomotor speed of 14 to 21 km/h. The discovery of a bonebed at Dry Island containing at least 26 individuals of different ages provided the strongest evidence of gregarious behavior among tyrannosaurids.

Cretáceous Carnivore 9m

US · 155–150 Ma

Allosaurus

Allosaurus fragilis

"Fragile different lizard"

Allosaurus fragilis was the apex predator of the Morrison Formation in the Late Jurassic, 155 to 150 million years ago. Up to 10.5 meters long and weighing around 2,300 kg, it was the largest carnivore in its ecosystem. Its skull was lightweight and highly fenestrated, reducing weight without sacrificing strength. Finite element analyses revealed the skull was designed to withstand vertical and horizontal tensile forces, suggesting a hatchet-style attack with the upper jaws rather than a simple closing bite. It had three fingers on each hand with curved claws up to 25 centimeters long. The Cleveland-Lloyd Quarry 9 in Utah has yielded over 10,000 Allosaurus bones, making it the best-sampled theropod in North America. It was the primary predator of juvenile sauropods, ornithopods, and stegosaurs.

Jurassic Carnivore 10.5m

AR · 129–122 Ma

Amargasaurus cazaui

"La Amarga lizard (honoring geologist Luis Cazau)"

Amargasaurus cazaui is one of the most recognizable sauropods of the Early Cretaceous, thanks to two parallel rows of extremely elongated neural spines running along its neck and back. Discovered in 1984 in the La Amarga Formation of Neuquén, Argentina, and described in 1991 by Leonardo Salgado and José Bonaparte, it is one of the best-preserved Early Cretaceous sauropod skeletons ever found. Measuring around 9 to 10 meters in length and approximately 2.6 metric tons, it was small for a sauropod, but its cervical spines, reaching up to 60 cm in height, made it unmistakable. Recent studies suggest these spines supported a skin sail, possibly used for thermoregulation or display.

Cretáceous Herbivore 10m

CN · 160.89–160.25 Ma

Anchiornis huxleyi

"Near bird (of Huxley)"

Anchiornis huxleyi is one of the smallest and most completely known dinosaurs in science, living approximately 160 million years ago in what is now northeastern China. At just 34 cm long and weighing between 110 and 250 grams, it had four feathered wings: two on the forelimbs and two on the hindlimbs. It became the first Mesozoic dinosaur to have its complete coloration reconstructed from direct fossil evidence: a red head, black and gray body, and white wing feathers with black tips. Its phylogenetic position as a basal anchiornithid places it centrally in debates about the origin of avian flight.

Jurassic Carnivore 0.6m

🇧🇷 BR

BR · 112–108 Ma

Anhanguera blittersdorffi

"Blittersdorff's evil spirit"

Anhanguera blittersdorffi is an anhanguerid pterosaur from the Lower Cretaceous of Brazil, described by Campos and Kellner in 1985 from an extraordinarily preserved three-dimensional skull. With an estimated wingspan of 4 to 4.5 meters, it was an aerial predator specialized in fish capture, bearing characteristic premaxillary crests, curved coniform teeth, and a rosette-shaped mandible. Originating from the calcareous nodules of the Romualdo Formation, Araripe Basin, in Ceará, it is one of the most studied Brazilian pterosaurs and an emblem of the Cretaceous fauna of northeastern Brazil.

Cretáceous Piscivore 4.5m

US · 68–66 Ma

Ankylosaurus

Ankylosaurus magniventris

"Fused lizard with great belly"

Ankylosaurus magniventris was the largest known ankylosaurid, living at the end of the Cretaceous 68 to 66 million years ago in North America. At about 8 meters long and 6 metric tons, it was a quadrupedal herbivore equipped with a complete body armor: osteoderms fused to the skull, bony plates along the back and flanks, and a massive tail club capable of shattering predator bones. Its sideways-facing nostrils are unique among ankylosaurs. Despite its imposing size, it was rare in its ecosystem, likely inhabiting upland areas distant from river margins where hadrosaurs and ceratopsians lived.

Cretáceous Herbivore 8m

US · 152–151 Ma

Apatosaurus

Apatosaurus ajax

"Deceptive lizard (Ajax, hero from Greek mythology)"

Apatosaurus ajax is the type species of the genus Apatosaurus, described by Othniel Charles Marsh in 1877 from bones discovered in Morrison, Colorado. One of the largest known diplodocids, it reached 21 to 22 meters in length and 16 to 22 tonnes. Its neck was notably more robust and thicker than those of its relatives Diplodocus and Brontosaurus, with ventrolaterally displaced cervical ribs. The species stood at the center of one of paleontology's greatest taxonomic controversies: the name Brontosaurus was considered its synonym for 112 years, until Tschopp, Mateus, and Benson (2015) demonstrated that Brontosaurus constitutes a distinct and valid genus.

Jurassic Herbivore 21m

DE · 152–148 Ma

Archaeopteryx

Archaeopteryx lithographica

"Ancient wing from the lithographic stone"

Archaeopteryx lithographica is one of the most famous and important fossils in the history of science. It lived approximately 150 million years ago during the Late Jurassic, on the islands covering what is now the German state of Bavaria. About 0.5 meters long and estimated at half a kilogram, it was roughly the size of a raven. It combined features of theropod dinosaurs, including teeth, claws, and a long bony tail, with true feathers and wing asymmetry typical of modern flying birds. Thirteen specimens have been found in the Solnhofen Limestone, including the celebrated Berlin Exemplar, considered the most iconic transitional fossil between dinosaurs and birds.

Jurassic Carnivore 0.5m

AR · 97–93 Ma

Argentinosaurus

Argentinosaurus huinculensis

"Argentina lizard from Huincul"

Argentinosaurus huinculensis is arguably the largest land animal that ever lived, with length estimates between 30 and 35 meters and mass up to 80 tonnes. Discovered in 1987 in Neuquén, Argentine Patagonia, and formally described in 1993 by José Bonaparte and Rodolfo Coria, it belongs to the clade Lognkosauria, a group of giant titanosaurs exclusive to South America. Its fossil record is fragmentary: only a few dorsal vertebrae, ribs, and part of the sacrum have been found, yet they are sufficient to confirm its extraordinary size. It coexisted with the largest terrestrial predator of the Cretaceous, Giganotosaurus carolinii, in a fauna that continues to fascinate paleontologists worldwide.

Cretáceous Herbivore 33m

GB · 130–125 Ma

Baryonyx

Baryonyx walkeri

"Walker's heavy claw"

Baryonyx walkeri is one of the best-documented piscivorous dinosaurs in the history of paleontology. It lived during the Barremian of the Early Cretaceous, approximately 130 to 125 million years ago, on the fluvial floodplains of what is now Surrey, England. At roughly 9.5 meters long and an estimated 1.7 metric tons, it had a long, narrow snout similar to a gharial's, packed with finely striated conical teeth. The first-finger claw, about 31 centimeters long, gave the animal its name. The holotype NHMUK PV R9951, discovered by William Walker in 1983, was found with fish scales and juvenile iguanodontid bones in the stomach region, providing direct evidence that Baryonyx fed on both fish and terrestrial prey.

Cretáceous Piscivore 9.5m

CA · 112–110 Ma

Nodosaur

Borealopelta markmitchelli

"Northern shield of Mark Mitchell"

Borealopelta markmitchelli is considered the best-preserved dinosaur ever discovered. Found in 2011 at an oil sands mine in Alberta, Canada, the specimen retained skin, osteoderms in life position, and even stomach contents. Around 5.5 meters long and 1.3 metric tons, it was a heavily armored quadrupedal nodosaurid, with large parascapular spines and countershaded coloration suggesting intense predation pressure despite its armor. It was described by Caleb Brown and colleagues in 2017.

Cretáceous Herbivore 5.5m

US · 154.8–143.1 Ma

Brachiosaurus

Brachiosaurus altithorax

"Arm lizard with high thorax"

Brachiosaurus altithorax is one of the largest dinosaurs ever discovered in North America. It lived during the Late Jurassic, approximately 154 to 143 million years ago, on the alluvial plains of the Morrison Formation. It is distinguished by forelimbs longer than its hindlimbs, an extremely long neck, and a high thorax, which allowed it to reach vegetation more than 9 meters above the ground. Originally described by Elmer Riggs in 1903, it was for decades confused with its African relative Giraffatitan brancai, whose definitive taxonomic separation only occurred in 2009. With more than 26 distinct skeletal characteristics, it represents an exclusively North American genus.

Jurassic Herbivore 22m

CA · 78.5–77.5 Ma

Brachylophosaurus canadensis

"Short-crested lizard of Canada"

Brachylophosaurus canadensis was a medium-sized hadrosaurid that lived during the Late Cretaceous, approximately 78 to 77 million years ago, on the coastal plains that now correspond to Montana (USA) and Alberta (Canada). Its name refers to the flat paddle-shaped nasal crest, relatively short compared to other hadrosaurids with elaborate crests. It became world-famous through the specimen known as 'Leonardo', an exceptional mummy preserving skin, tendons, and even stomach contents, recognized by Guinness as the best-preserved dinosaur ever found. It possessed a sophisticated dental battery for processing tough vegetation.

Cretáceous Herbivore 9m

US · 156–146 Ma

Brontosaurus

Brontosaurus excelsus

"Noble thunder lizard"

Brontosaurus excelsus is one of the most iconic sauropods in the history of paleontology. It lived during the Late Jurassic, 156 to 146 million years ago, across the semi-arid floodplains of what is now the western United States. Up to 22 meters long and approximately 17 metric tons, it was one of the largest herbivores in its ecosystem. Its long, robust neck, far thicker than that of relatives like Diplodocus, may have served intraspecific combat roles in addition to feeding. Synonymized with Apatosaurus in 1903 by Elmer Riggs, the genus was revalidated in 2015 by Tschopp, Mateus, and Benson following the most comprehensive phylogenetic analysis ever conducted on diplodocids.

Jurassic Herbivore 22m

US · 155–145 Ma

Camarasaurus

Camarasaurus supremus

"Supreme chambered lizard"

Camarasaurus supremus is the type species and largest member of the genus Camarasaurus, the most common sauropod of the Morrison Formation. Described by Edward Drinker Cope in 1877 from material discovered in Colorado, it was one of the first large North American sauropods to be studied systematically. It is distinguished by its tall, short skull with enormous external nostrils and particularly robust spoon-shaped teeth, adapted for a diet of tough vegetation such as tree ferns and conifers. At up to 23 meters in length and over 40 tonnes, it was the largest herbivore of its ecosystem.

Jurassic Herbivore 21m

MA · 99–94 Ma

Carcharodontosaurus

Carcharodontosaurus saharicus

"Shark-toothed lizard of the Sahara"

Carcharodontosaurus saharicus was one of the largest terrestrial predators that ever lived. It inhabited northern Africa approximately 99 to 94 million years ago during the Cenomanian stage of the Cretaceous, sharing its ecosystem with Spinosaurus. Its name means 'shark-toothed lizard of the Sahara,' a reference to the sharp serrations on its teeth, which measured up to 6.5 centimeters. At roughly 12.5 meters long with a 1.6-meter skull, it rivaled T. rex in size but had different biomechanics, specializing in slicing flesh from large sauropods rather than crushing bone. The neotype skull SGM-Din 1 was discovered by Paul Sereno in 1995 in the Kem Kem Beds of Morocco.

Cretáceous Carnivore 12.5m

AR · 72–69 Ma

Carnotaurus

Carnotaurus sastrei

"Meat-eating bull of Sastre"

Carnotaurus sastrei is one of the most distinctive predators of the Late Cretaceous of Patagonian Argentina. It stands apart from all other carnivorous dinosaurs by its pair of robust bony horns above the eyes, a feature that gave it the name 'meat-eating bull'. At approximately 8 meters long and 1.5 metric tons, it had a deep, compressed skull, extremely reduced vestigial forelimbs, and long muscular hind legs adapted for speed. It is the only theropod with extensive preserved skin impressions, revealing a mosaic of ~5 mm scales with no evidence of feathers.

Cretáceous Carnivore 8m

US · 153–148 Ma

Ceratosaurus nasicornis

"Horned lizard with nasal horn"

Ceratosaurus nasicornis was one of the most distinctive predators of the Late Jurassic of North America. It lived approximately 153 to 148 million years ago in the Morrison Formation, sharing its ecosystem with Allosaurus and Torvosaurus. Its most striking feature is a prominent bony horn on the midline of the snout, along with a pair of ridges over the eyes. It was also the only theropod known to have osteoderms: small bony plates running along the dorsal midline. At roughly 6 meters long and 500 kg, it was an agile mid-sized predator, formally described by Othniel Charles Marsh in 1884.

Jurassic Carnivore 6m

CA · 76.5–75 Ma

Chasmosaurus

Chasmosaurus belli

"Bell's opening lizard"

Chasmosaurus belli is the prototype ceratopsid of the subfamily Chasmosaurinae, which bears its name. It lived in the late Campanian of the Cretaceous, approximately 76.5 to 75 million years ago, in Alberta, Canada, and is one of the first large ceratopsids described by science. Its most distinctive feature is the parieto-squamosal frill that is extraordinarily large relative to the skull, with two large oval openings (the parietal fenestrae) that substantially reduced the weight of the structure. The genus name Chasmosaurus refers precisely to these openings: 'khasma' in Greek means opening or chasm. This long frill, which could exceed 60% of the total skull length, is the morphological signature of the entire subfamily. The animal was originally described by Lawrence Lambe in 1902 based on fragmentary material from the Dinosaur Park Formation, but the species was only definitively established by Lambe in 1914. Subsequent studies by Brown and Schlaikjer (1940) and Dodson (1990, 1996) substantially refined the anatomy and systematics of the taxon. Chasmosaurus belli is distinguished from other species in the genus (such as C. russelli and C. irvinensis, now reclassified as Vagaceratops) mainly by the dimensions and proportions of the frill and by the relatively short facial horns. The nasal horn is low and laterally compressed, while the supraorbital horns range from short to moderate. In 2010, a juvenile specimen of Chasmosaurus belli was discovered by Brian Campione at Dinosaur Provincial Park and studied by Phillip Bell and colleagues. The importance of this fossil goes beyond the rarity of juveniles in ceratopsids: it preserved mummified skin impressions in different regions of the body, including large hexagonal scales on the flanks, smaller scales on the neck and face, and scales organized in a differentiated pattern around the eye. Pigmentation analyses preserved through scanning electron microscopy revealed melanosomes suggesting contrasting pigmentation, possibly with a counter-shading pattern (dark dorsum, pale ventrum), which would be the first direct evidence of coloration in a ceratopsid. Chasmosaurus belli's position as the founding taxon of Chasmosaurinae makes it fundamental for understanding the evolution of the entire subfamily. Modern phylogenetic analyses consistently position C. belli as one of the most basal chasmosaurines, from which more derived forms with even more elaborate frills radiate, including Pentaceratops, Anchiceratops, Torosaurus, and Triceratops. The fossil record of Chasmosaurus belli in the Dinosaur Park Formation is one of the richest of any ceratopsid, with dozens of specimens collected over more than a century of systematic excavations.

Cretáceous Herbivore 4.9m

US · 215–200 Ma

Coelophysis

Coelophysis bauri

"Hollow form (referring to its hollow bones)"

Coelophysis bauri is one of the oldest and best-known dinosaurs in the world. It lived in the Late Triassic, 215 to 200 million years ago, in what is now the southwestern United States. At up to 3 meters long and roughly 20 kg, it was an agile, fast predator built to chase small prey at high speed. Its hollow bones, which gave the genus its name, were an adaptation to reduce weight without sacrificing structural strength. In 1947, hundreds of skeletons were discovered at Ghost Ranch, New Mexico, forming one of the largest Triassic dinosaur deposits ever found. Coelophysis was the second dinosaur to travel to space: a skull was carried aboard the Space Shuttle Endeavour in 1998.

Triassic Carnivore 3m

DE · 150–145 Ma

Compsognathus

Compsognathus longipes

"Elegant jaw"

Compsognathus longipes was for more than a century the smallest known non-avian dinosaur, an agile and delicate theropod of the Late Jurassic (Tithonian, ~150-145 Ma) that inhabited the margins of shallow archipelagos in what is now central Europe. The holotype BSP AS I 563, preserved in the Solnhofen lithographic limestones of Bavaria, revealed an animal approximately 89 cm long with very short forelimbs, a long flexible neck, and a gracile skull with small pointed teeth. A lizard preserved inside the holotype's torso provided direct evidence of feeding behavior: Compsognathus actively hunted small prey, swallowing them whole or in large pieces. The second known specimen, MNHN CNJ 79, recovered at Canjuers in the French Provence, is substantially larger — about 1.25 m long — which generated decades of debate about whether it represented adults of C. longipes or a distinct species (Compsognathus corallestris, proposed by Bidar et al. in 1972), a question now resolved in favor of ontogenetic variation within a single species.

Jurassic Carnivore 1.2m

ES · 130–125 Ma

Concavenator corcovatus

"Hunchbacked hunter from Cuenca"

Concavenator corcovatus is a carcharodontosaurid from the Early Cretaceous of Spain, described in 2010 by Ortega, Escaso, and Sanz from a nearly complete skeleton found at the Las Hoyas site in Cuenca. Its most striking feature is a dorsal hump formed by the extreme elongation of the last two dorsal vertebrae, creating a short crest or sail above the hip region. The specimen also shows small bumps on the ulna interpreted as possible quill knob attachment points, making it the most basal non-avian theropod known with this evidence. Measuring approximately 6 meters long and weighing around 400 kg, it was the apex predator of its lacustrine ecosystem in Cretaceous Iberia.

Cretáceous Carnivore 6m

CN · 125–120 Ma

Confuciusornis

Confuciusornis sanctus

"Sacred Confucius bird"

Confuciusornis sanctus is the most abundant Mesozoic bird in the world fossil record: hundreds of specimens, many exquisitely preserved with feathers, have been extracted from the Yixian and Jiufotang formations of Liaoning, northeastern China. This unparalleled abundance made Confuciusornis the most studied extinct bird taxon in the world, capable of providing data on morphology, ontogeny, coloration, paleoecology, and social behavior simply not accessible for rarer birds. It lived during the Barremian to Aptian of the Early Cretaceous, approximately 125 to 120 million years ago, and represents one of the most important morphological innovations in bird history: it was the first toothless Mesozoic bird with a true horny beak and a fused tail bone forming a pygostyle. Confuciusornis morphology combines primitive and derived features remarkably. On one hand, the forelimbs retain three functional clawed fingers, and the skull retains some primitive skeletal features relative to modern birds. On the other, the complete absence of teeth, the horny beak, and the pygostyle are innovations we know mainly from modern birds, making Confuciusornis much more externally similar to a modern bird than Archaeopteryx or other contemporaries. The tail, short due to the pygostyle, accommodated in long-tailed forms a pair of very long, narrow ribbon-like rectrices whose function was probably social display. The presence or absence of these tail feathers in different specimens has historically been interpreted as sexual dimorphism, but recent analyses with ontogenetically comparable specimens question this simple interpretation. Confuciusornis flight is considered truly active, not just gliding: the sternum morphology, with well-developed keel for flight muscle insertion, and wing proportions suggest sustained powered flight capability. However, biomechanical analyses indicate the flight pattern would differ from modern birds: the shoulder joint, clavicle position, and relative proportions of humerus and ulna suggest an aerodynamically less efficient flight style compared to neornithean birds. Bone histology studies show Confuciusornis had slower growth rates than modern birds of comparable size, reaching skeletal maturity in one or two years, closer to reptiles than to modern birds.

Cretáceous Omnivore 0.5m

CA · 77–75 Ma

Corythosaurus casuarius

"Cassowary-helmeted lizard"

Corythosaurus casuarius was one of the most striking hadrosaurids of the Late Cretaceous, living 77 to 75 million years ago on the coastal plains of North America. Its name honors the cassowary, a modern bird with a prominent bony helmet, a direct reference to the large hollow helmet-shaped crest that dominated the top of the skull. That crest was no empty ornament: it contained S-shaped nasal passages that functioned as a resonating chamber, amplifying low-frequency vocalizations used in social communication. Measuring up to 9 meters and weighing around 3.8 metric tons, it is one of the best-documented dinosaurs from the Dinosaur Park Formation.

Cretáceous Herbivore 9m

AQ · 194–182 Ma

Elvisaurus

Cryolophosaurus ellioti

"Elliott's frozen-crested lizard"

Cryolophosaurus ellioti was the largest predator of the Early Jurassic in Antarctica and the first large-bodied theropod described from the continent. At roughly 6.5 meters long and an estimated 465 kg, it was distinguished by a unique transverse crest on the skull, formed by the lacrimal bones and oriented perpendicular to the snout axis, unlike any other known dinosaur. This feature earned it the informal nickname 'Elvisaurus.' Discovered in 1991 by paleontologist William Hammer in the Transantarctic Mountains, the holotype (FMNH PR1821) was extracted from over 2,300 kg of rock and represents a subadult. Its phylogenetic position is debated, placing it as a basal neotheropod close to Averostra.

Jurassic Carnivore 6.5m

CA · 77–74 Ma

Daspletosaurus torosus

"Frightful and muscular lizard"

Daspletosaurus torosus was one of the largest terrestrial predators of the Campanian in North America, approximately 9 meters long and weighing 2.5 metric tons. It inhabited what is now Alberta, Canada, between 77 and 74 million years ago. A member of the tribe Daspletosaurini within the family Tyrannosauridae, it was a direct ancestor in the lineage leading to Tyrannosaurus rex. It possessed the largest teeth among tyrannosaurids of its time, proportionally larger than those of T. rex itself, and was the first tyrannosaurid for which stomach contents were identified, revealing it preyed on hadrosaurs. Healed bite marks on skulls indicate intraspecific combat.

Cretáceous Carnivore 9m

MN · 72–66 Ma

Deinocheirus mirificus

"Peculiar horrible hand"

Deinocheirus mirificus was one of paleontology's greatest mysteries for nearly 50 years. Discovered in 1965 in Mongolia only through its gigantic arms — 2.4 meters with curved claws — it remained bodyless until 2014, when two nearly complete skeletons were described by Lee et al. in Nature. The result astonished: the largest known ornithomimosaur measured about 11 meters, weighed 6.4 tons, possessed a dorsal sail formed by tall neural spines, a broad hadrosaur-like bill, and an omnivorous diet including fish and aquatic plants.

Cretáceous Omnivore 11m

US · 119–108 Ma

Deinonychus

Deinonychus antirrhopus

"Terrible claw without counterpart (reference to the sickle-shaped claw on the second toe)"

Deinonychus antirrhopus was one of the most sophisticated predators of the Early Cretaceous of North America. At approximately 3.4 meters long and 85 kg, it was distinguished by an enormous sickle-shaped claw on the second toe, measuring over 12 centimeters. Described by John Ostrom in 1969, Deinonychus revolutionized paleontology by demonstrating that dinosaurs could be agile, active animals, possibly endothermic. This discovery initiated the so-called 'Dinosaur Renaissance' and directly influenced the creation of Jurassic Park. The animal was also pivotal in establishing the hypothesis that birds are descended from theropod dinosaurs.

Cretáceous Carnivore 3.4m

US · 196–183 Ma

Dilophosaurus

Dilophosaurus wetherilli

"Two-crested lizard (honoring John Wetherill)"

Dilophosaurus wetherilli was the largest land predator in North America during the Early Jurassic, reaching about 7 meters in length and 400 kg. Its most distinctive feature was a pair of parallel crests running along the top of its skull, thin and delicate structures that likely served for visual display and species recognition. It lived approximately 196 to 183 million years ago in the Kayenta Formation of present-day Arizona, USA. The comprehensive anatomical revision by Marsh and Rowe (2020) confirmed the animal had robust jaws strong enough to puncture bone, overturning the notion it was a weak predator. There was no frill and no venom: these elements are inventions of the film Jurassic Park (1993).

Jurassic Carnivore 7m

US · 154–152 Ma

Diplodocus

Diplodocus carnegii

"Carnegie's double beam"

Diplodocus carnegii is one of the largest animals ever to walk the Earth, reaching about 26 meters in length. It lived during the Late Jurassic, 154 to 152 million years ago, on the semi-arid plains of the Morrison Formation in the western United States. Its long neck and slender, whip-like tail served as counterweights. Peg-like teeth set only at the front of the jaw were specialized for raking low vegetation. The species was named in honor of industrialist Andrew Carnegie, who funded the excavation of the holotype specimen CM 84 in 1899. Plaster casts of its skeleton were distributed to museums worldwide, making Diplodocus carnegii the most-viewed dinosaur on the planet.

Jurassic Herbivore 26m

US · 66–66 Ma

Dracorex

Dracorex hogwartsia

"Dragon king of Hogwarts"

Dracorex hogwartsia is one of the dinosaurs with the most peculiar story in paleontology: it was named by children, in honor of a fictional school of witchcraft, and its status as a valid species is one of the most contentious taxonomic debates of the Late Cretaceous. Described in 2006 by Robert Bakker and collaborators based on a nearly complete skull discovered in the Hell Creek of South Dakota by a group of amateur fossil hunters, the animal presented a cranial morphology radically different from other known pachycephalosaurids: the skull was long, low, and flat, without any trace of a bony dome, but decorated with an impressive series of horns and nodules along the frontoparietal and temporal region. The visual result is, in fact, remarkably similar to medieval descriptions of dragons, which inspired the specimen's donors, children from the Children's Museum of Indianapolis, to propose the name to the paleontologist. The main scientific controversy surrounding Dracorex was raised in 2009, when Jack Horner and Mark Goodwin published a detailed histological analysis of the skull. Upon examining the microstructure of the frontoparietal bone, they found immature bone tissue (fibrolamellar, with abundant vasculature and without complete remodeling) characteristic of young individuals, not adults with completed bone growth. Horner and Goodwin's hypothesis is that Dracorex hogwartsia is not a distinct species, but rather a juvenile of Pachycephalosaurus wyomingensis: the flat skull with horns would be the initial state, and the dome would form progressively during growth, similar to the development of horns in sheep. This interpretation would also unify Stygimoloch spinifer as a teenager of Pachycephalosaurus, consolidating three names into a single taxon. The synonymy proposal, while widely accepted by many specialists, remains formally controversial. Other researchers, such as Robert Sullivan (2006) and David Evans and collaborators (2013), argue that the morphological differences between the skulls are too pronounced to be explained by ontogeny alone, and that Dracorex may represent a distinct lineage of flat-skulled pachycephalosaurids that lived in sympatry with Pachycephalosaurus. The question is complicated by the rarity of specimens: only one Dracorex skull is known with certainty, making it impossible to establish complete ontogenetic series. Regardless of taxonomic resolution, the Dracorex skull is one of the most extraordinary known among ornithischian dinosaurs. The tubercles, spines, and nodules covering the cranial surface have no parallel in any other pachycephalosaurid, and their function continues to be debated: they may have served for intraspecific recognition, surface thermoregulation, sexual display, or passive defense. The preservation of the specimen, with unusually well-conserved cranial surface details, has made Dracorex one of the most studied and artistically represented dinosaurs of the last twenty years.

Cretáceous Herbivore 2.4m

AR · 77–70 Ma

Dreadnoughtus

Dreadnoughtus schrani

"Fears nothing (honoring Adam Schran, donor who funded the excavations)"

Dreadnoughtus schrani was one of the largest land animals ever to exist. Discovered in Patagonian Argentina in 2005 by Kenneth Lacovara and formally described in 2014, this giant titanosaur lived between 77 and 70 million years ago, during the Late Cretaceous. At roughly 26 meters long and an estimated mass of 65 tonnes, it was the size of a dozen African elephants. The holotype is one of the most complete giant titanosaur skeletons ever found, with approximately 70% of the bones preserved, making it exceptional for an animal of this size. The genus name references the dreadnought battleships of the early 20th century, warships so powerful they 'feared nothing.' The species honors Adam Schran, the philanthropist who funded the field expeditions.

Cretáceous Herbivore 26m

US · 73–66 Ma

Edmontosaurus annectens

"Edmonton lizard (connected)"

Edmontosaurus annectens was one of the largest and most abundant herbivores of the late North American Cretaceous. Up to 12 meters long and around 5.6 metric tons, it roamed in herds across the floodplains of the Hell Creek Formation 73 to 66 million years ago. Its broad, flat snout, typical of hadrosaurs, housed a sophisticated dental battery of hundreds of replacement teeth adapted for grinding fibrous vegetation. It is famous for the 'mummy' AMNH 5060, a specimen with preserved skin revealing polygonal scales and soft tissue, and for evidence of predation by Tyrannosaurus rex.

Cretáceous Herbivore 12m

AR · 231–228 Ma

Eoraptor

Eoraptor lunensis

"Dawn thief (of the moon)"

Eoraptor lunensis is one of the oldest dinosaurs known to science. It lived approximately 231 million years ago during the Late Triassic (Carnian stage) in what is now San Juan Province, Argentina. At only 1.2 meters long and roughly 10 kg, it was a small, agile biped with heterodont dentition: serrated recurved teeth at the front of the jaw and leaf-shaped teeth toward the back, suggesting an omnivorous diet. Described by Sereno et al. in 1993 from a nearly complete skeleton, Eoraptor offers a unique window into dinosaur origins and the Triassic ecosystem of Gondwana.

Triassic Omnivore 1.2m

CA · 76.5–66 Ma

Euoplocephalus

Euoplocephalus tutus

"Well-armored and protected head"

Euoplocephalus tutus is the best-documented ankylosaur in the history of paleontology: more than 40 specimens have been collected since the original description in 1902, including several complete skulls, dermal armor in association, and at least one complete tail with preserved bony club. It lived in the late Campanian of the Cretaceous, approximately 76.5 to 66 million years ago, in North America, with records in Alberta (Canada) and possibly Montana (USA). It is the only ankylosaur for which sufficient material exists to characterize individual and ontogenetic morphological variation within the species with any degree of confidence. The animal had extensive dermal armor composed of osteoderms of multiple types: large flat plates on the back, cones or spines along the flanks, smaller scales filling the spaces between larger ones, and a hardened skin covering over the skull. Notably, Euoplocephalus had ossified eyelids, a unique adaptation protecting the eyes from predatory attacks. The tail terminated in a bony club (fused tail osteoderm, the 'golf club') whose size and robustness were analyzed by Arbour (2009) as sufficient to generate impact forces capable of fracturing bones of large predators like Tyrannosaurus and Gorgosaurus. In terms of systematics, the history of Euoplocephalus is complex. Many ankylosaur specimens from Alberta were originally referred to E. tutus based on the assumption that there would be only one ankylosaur species per formation. More recent research by Arbour and Currie (2013, 2015) reassessed this material and concluded that several specimens previously referred to E. tutus belong to distinct genera and species (such as Scolosaurus cutleri, Anodontosaurus lambei, and Dyoplosaurus acutosquameus). After this revision, the number of specimens truly referable to E. tutus decreased, but the taxon remains the best-characterized ankylosaur of the Campanian of North America. Arbour's (2009) biomechanical analysis of the tail club is one of the most cited results in ankylosaur paleobiology: using structural mechanics models and comparisons with modern hammers, Arbour demonstrated that the E. tutus club could generate impact forces of 2-6 kN, sufficient to fracture the ribs or tibiae of Tyrannosaurus or Gorgosaurus. Tail musculature, inferred from well-developed transverse processes, was capable of moving the club in high-speed lateral arcs. This analysis changed the scientific understanding of the tail club from a possible display ornament to an active and effective defensive weapon.

Cretáceous Herbivore 6m

AR · 90–86 Ma

Futalognkosaurus

Futalognkosaurus dukei

"Giant chief lizard (from the Mapuche language)"

Futalognkosaurus dukei is one of the most complete titanosaurs ever discovered, with approximately 70% of the skeleton preserved across three specimens. Found in 2000 on the shores of Lake Barreales in Neuquén, Argentine Patagonia, it was formally described in 2007 by Calvo, Porfiri, González-Riga, and Kellner. With length estimates ranging from 24 to 30 meters, it belonged to the clade Lognkosauria, a group of giant titanosaurs that also includes Mendozasaurus and possibly Argentinosaurus. Its cervical vertebrae with extraordinarily tall neural spines, exceeding one meter, distinguish it from other sauropods and suggest unique adaptations for neck muscle support.

Cretáceous Herbivore 26m

MN · 72–66 Ma

Gallimimus

Gallimimus bullatus

"Chicken mimic with bulla"

Gallimimus bullatus is the largest known ornithomimosaur, living approximately 70 million years ago in what is now Mongolia. At up to 6 meters long and around 440 kg, it was a swift biped capable of reaching between 42 and 56 km/h. Toothless, it had a rounded keratinous beak and long neck, adapted to an apparently herbivorous diet. Discovered during Polish-Mongolian expeditions in the 1960s, it became the most complete and well-documented ornithomimosaur of the Cretaceous, and gained worldwide fame by appearing in the herd stampede scene of the 1993 film Jurassic Park.

Cretáceous Herbivore 6m

AR · 99–95 Ma

Giganotosaurus

Giganotosaurus carolinii

"Giant southern lizard"

Giganotosaurus carolinii was one of the largest terrestrial predators ever known, with an estimated length of up to 13 meters and mass around 7 tonnes. Discovered in 1993 by Rubén Carolini in the Candeleros Formation of Neuquén, Argentina, and described by Coria and Salgado in 1995, it belongs to the family Carcharodontosauridae. Its skull measured 1.56 m, larger than that of T. rex, with serrated teeth resembling shark teeth. It lived during the Cenomanian (~99–95 Ma), sharing its ecosystem with giant titanosaurs like Andesaurus and Argentinosaurus. Isotope analysis of bones suggests an intermediate metabolism between reptiles and mammals, and computer simulations indicate a maximum running speed of approximately 14 m/s.

Cretáceous Carnivore 13m

TZ · 154–150 Ma

Giraffatitan

Giraffatitan brancai

"Giraffe titan"

Giraffatitan brancai was a giant brachiosaurid sauropod that lived during the Kimmeridgian to Tithonian of the Late Jurassic, approximately 154 to 150 million years ago, in what is now Tanzania. At 26 meters in length and estimated body mass of 35,000 to 40,000 kg, it was one of the largest land animals of its time. Giraffatitan's morphology is characterized by forelimbs significantly longer than the hindlimbs, resulting in a forward-sloping back and an extremely long and high neck that allowed the animal to reach the vegetation of tree canopies in the East African Jurassic forest. Unlike many sauropods that held the neck horizontally, Giraffatitan's skeletal proportions indicate the neck was raised at a steep angle, giving the animal a vertical silhouette reminiscent of a giraffe, hence the name. The separation of Giraffatitan from Brachiosaurus as a distinct genus was proposed by Paul (1988) and confirmed by Taylor (2009) after detailed cladistic analysis. Key anatomical differences include skull configuration, taller and with a more prominent nasofrontal crest in Giraffatitan, and cervical vertebrae proportions, more elongate and with lower robustness index in Giraffatitan than in Brachiosaurus altithorax from North America. The validity of Giraffatitan as a separate genus is currently consensus in the paleontological community, though some authors have suggested both could belong to the same genus with subgenus status. Fossil material of Giraffatitan brancai is exceptionally rich for a giant sauropod: German expeditions to Tanzania between 1909 and 1913, led by Werner Janensch, recovered remains of dozens of individuals, including materials from at least five partially articulated individuals. The composite specimen HMN SII, mounted at the Museum für Naturkunde in Berlin, is the tallest mounted dinosaur skeleton in the world, at 13.27 meters. The logistical operation of the Tendaguru expeditions was one of the largest paleontological endeavors in history: more than 250 African workers transported hundreds of tons of fossilized material over 60 kilometers from the East African coast under extremely adverse conditions.

Jurassic Herbivore 26m

CA · 77–75 Ma

Gorgosaurus libratus

"Balanced fierce lizard"

Gorgosaurus libratus was one of the apex predators of the North American Campanian, living 77 to 75 million years ago in what is now Alberta, Canada, and Montana, USA. Measuring roughly 8 to 9 meters in length and weighing approximately 2,400 kg, it was smaller than Tyrannosaurus rex but shared its bipedal stance, reduced forelimbs, and powerful jaws. It is considered the best-represented tyrannosaurid in the fossil record, with dozens of specimens spanning a full ontogenetic series from juvenile to adult. Bone histology studies have revealed detailed growth patterns, and a juvenile with preserved stomach contents demonstrated that young individuals hunted small prey while adults targeted hadrosaurs and ceratopsians.

Cretáceous Carnivore 9m

AR · 231–229 Ma

Herrerasaurus ischigualastensis

"Herrera's lizard from Ischigualasto"

Herrerasaurus ischigualastensis is one of the most primitive known dinosaurs, living approximately 231 to 229 million years ago in South America. Up to 6 meters long and around 350 kg, it was the apex predator of the Ischigualasto Formation ecosystem in Argentina. An agile biped, it had forelimbs specialized for grasping prey and a unique intramandibular joint in its lower jaw that enhanced prey capture and retention. Its phylogenetic position remains debated: classified variously as a basal theropod or as a pre-eusaurischian saurischian. The complete skull, discovered by Sereno and Novas in 1988, revolutionized understanding of the earliest dinosaurs.

Triassic Carnivore 6m

ZA · 201–196 Ma

Heterodontosaurus

Heterodontosaurus tucki

"Tuck's different-toothed lizard"

Heterodontosaurus tucki is one of the most primitive ornithischians known and certainly the most anatomically surprising of its time. It lived in the Early Jurassic, approximately 201 to 196 million years ago, on the semi-arid plains of what is now South Africa, in the Upper Elliot Formation. At only 1.2 meters in length and under 2 kg, it was an agile biped with long hind limbs and relatively robust forelimbs, likely using its hands to manipulate vegetation or small prey. Its skeleton is extraordinarily well preserved, with the skull SAM-PK-K1332 being one of the most complete among primitive Triassic-Jurassic dinosaurs. The defining feature of the genus, reflected in its name, is its radically heterogeneous dentition: unlike the vast majority of herbivorous dinosaurs, Heterodontosaurus possessed three distinct types of teeth. At the front of the upper jaw were small incisor-like teeth for cropping vegetation, followed by large canine-like tusks at the corners of the maxilla and dentary, and taller, laterally compressed cheek teeth with crushing edges for processing plant food. This combination of three distinct dental morphologies in a single animal is unique among Dinosauria and generated decades of debate about function and diet. The question of the tusks is the most controversial aspect of Heterodontosaurus biology. Crompton and Charig, when describing the species in 1962, suggested omnivorous use. Later studies, especially those of Santa Luca (1980) and Sereno (2012), raised the hypothesis of sexual dimorphism: the tusks would be exclusive to males and would function in display or intraspecific combat, analogous to modern deer and suids. Norman et al. (2011), upon reexamining the material, concluded that the canine teeth were not related to carnivory but rather to social behavior. Porro et al. (2011) performed biomechanical analysis of the jaw and confirmed that its structure was highly adapted to processing hard plant material. Heterodontosaurus is also notable for its phylogeny. For decades it was placed at the base of ornithopods, but modern analyses position it at the base of Ornithischia or as a member of a lineage sister to Genasauria. This makes it a valuable window into the early stages of ornithischian dinosaur evolution, before the great diversification that produced hadrosaurs, ceratopsians, ankylosaurs, and stegosaurs. Additionally, possible evidence of keratin on the anterior teeth suggests a partial horny beak, as in many modern birds and turtles.

Jurassic Omnivore 1.2m

GB · 130–125 Ma

Hypsilophodon

Hypsilophodon foxii

"High-ridged tooth (from the Isle of Wight)"

Hypsilophodon foxii was a small bipedal ornithopod from the Early Cretaceous of the Isle of Wight, England. Measuring about 1.8 meters in length and weighing just 20 kg, it was an agile, fast-running herbivore adapted for life on savanna-like floodplains. Described by Thomas Henry Huxley in 1869 from a skull collected by Reverend William Fox, the species endured decades of misinterpretation: early 20th-century researchers incorrectly depicted it as an arboreal climber. Peter Galton, in papers published between 1969 and 1974, definitively refuted this hypothesis, establishing Hypsilophodon as a specialized terrestrial runner with long hind legs and a stiff tail for balance.

Cretáceous Herbivore 1.8m

BE · 126–122 Ma

Iguanodon

Iguanodon bernissartensis

"Iguana tooth from Bernissart"

Iguanodon bernissartensis was one of the first dinosaurs described by science and remains one of the most studied. Initially discovered in 1822 by Gideon Mantell in England and renamed after the extraordinary discovery of 38 complete skeletons in Bernissart, Belgium, in 1878, this Early Cretaceous herbivorous ornithopod measured up to 11 meters and weighed around 4.5 tonnes. Its conical thumb spike is one of its trademarks, and modern biomechanics analyses indicate it was an obligate quadruped. It lived during the Barremian-Aptian (~126–122 Ma) in rich ecosystems of western Europe.

Cretáceous Herbivore 11m

🇧🇷 BR

BR · 115–108 Ma

Irritator

Irritator challengeri

"Challenging irritator (named after Professor Challenger)"

Irritator challengeri is a Brazilian spinosaurid discovered in the Romualdo Formation, Araripe Basin, Ceará state. Its name reflects paleontologists' frustration upon finding the original skull had been fraudulently modified by fossil traffickers before reaching scientists. About 8 meters long with an elongated snout lined with conical teeth, it was likely piscivorous, hunting giant fish in the lagoonal environments of the Early Cretaceous of Brazil. The holotype (SMNS 58022), housed in Stuttgart, Germany, is the most complete spinosaurid skull ever found, making Irritator essential for understanding the biology of the entire Spinosauridae family.

Cretáceous Piscivore 8m

TZ · 155–152 Ma

Kentrosaurus aethiopicus

"Spiky lizard of Ethiopia (Africa)"

Kentrosaurus aethiopicus was an African stegosaurid from the Late Jurassic, discovered in the Tendaguru Formation of Tanzania. At roughly 4.5 meters long and up to 1,000 kg, it was smaller than its North American relative Stegosaurus but equally impressive. Its most distinctive feature was the combination of small bony plates on the neck and anterior back with long, sharp spines on the tail and hip region — a formidable defensive arsenal. Biomechanical studies have shown its tail could sweep through a 180-degree arc fast enough to cause serious injury to predators. Originally described by Edwin Hennig in 1915, it is known from hundreds of bones collected during the German expedition to East Africa between 1909 and 1912.

Jurassic Herbivore 4.5m

US · 76.4–75.5 Ma

Kosmoceratops

Kosmoceratops richardsoni

"Richardson's ornate horned face"

Kosmoceratops richardsoni is the ceratopsian with the most elaborate cranial ornamentation ever documented in dinosaur history: a total of 15 horns and bony structures on the skull, including a large downward-curved nasal horn, two supraorbital horns above the eyes, two jugal horns, two laterally-directed epijugal horns, and ten forward-curving apical processes on the parieto-squamosal frill. No other known dinosaur or fossil vertebrate has such dense and diversified cranial ornamentation. The animal lived approximately 76 to 75.5 million years ago during the late Campanian stage of the Cretaceous, in the region corresponding to the present-day state of Utah in the United States. Kosmoceratops belonged to the fauna of the southern portion of Laramidia Island, a large continental island that existed during the Late Cretaceous when the Western Interior Seaway divided North America into two landmasses. Notably, the southern and northern portions of Laramidia were separated by a shallow internal sea and presented completely distinct dinosaur faunas: while the south (where Kosmoceratops lived) had short-frilled ceratopsians with elaborate ornamentation, the north produced forms with longer frills. This geographic faunal difference was one of the central arguments presented by Sampson et al. (2010) in the paper describing the species. The holotype and referred specimens were collected from the Kaiparowits Formation in southern Utah, one of the most productive Late Cretaceous geological units in North America. The formation dates from the late Campanian (~76.6 to 74.5 Ma) and preserves a rich subtropical ecosystem with multiple species of dinosaurs, crocodilians, turtles, lizards, mammals, and amphibians. Kosmoceratops fossils were collected by the Utah Museum of Natural History between 2004 and 2006 at sites within the Grand Staircase-Escalante National Monument. The function of the extravagant cranial ornamentation is a subject of ongoing scientific debate. Sampson et al. (2010) argue that the structures were primarily for intraspecific display and species recognition, analogous to the horns of modern antelopes and cervids. The fact that the supraorbital horns and frill processes face laterally and forward rather than forward in combat position supports the display hypothesis over the defensive one. Later biomechanical analyses by Mallon and Anderson (2013) suggest that ceratopsids used their horns in ritualized intraspecific combat, not as defense against large predators.

Cretáceous Herbivore 4.5m

US · 77–74 Ma

Maiasaura peeblesorum

"Good mother lizard of Peebles"

Maiasaura peeblesorum was a large hadrosaurid that lived during the Late Cretaceous, approximately 77 to 74 million years ago, on the coastal plains of what is now Montana, USA. Described by Jack Horner and Robert Makela in 1979, its name means 'good mother lizard', a direct reference to nesting colonies discovered at Egg Mountain, where eggs, hatchlings, and adults were found together, providing evidence of parental care. With over 200 known specimens across all age ranges, it is one of the best-documented dinosaurs. It is also notable for being the first dinosaur to travel to space.

Cretáceous Herbivore 9m

MG · 70–66 Ma

Majungasaurus

Majungasaurus crenatissimus

"Mahajanga lizard with serrated teeth"

Majungasaurus crenatissimus was the apex predator of Late Cretaceous Madagascar, living 70 to 66 million years ago. Measuring around 7 meters long and over one metric ton, it was a robust-skulled abelisaurid with a unique cranial horn on top of its snout and extremely reduced, vestigial arms. It belonged to a group of Gondwanan theropods that diversified in isolation from the rest of the world. It is notable for being the only non-avian theropod with direct evidence of cannibalism: bones of its own species bear tooth marks identical to those of its jaws.

Cretáceous Carnivore 7m

CN · 161–155 Ma

Mamenchisaurus constructus

"Horse-gate stream lizard"

Mamenchisaurus constructus is the dinosaur that holds, proportionally, the longest neck of any known animal. Discovered in 1952 during highway construction in Sichuan Province, China, and described in 1954 by paleontologist C. C. Young, this Late Jurassic giant belonged to Mamenchisauridae, an exclusively Asian family of extraordinarily long-necked sauropods. With a total estimated length of 21 to 26 meters and a weight of up to 15 tonnes, it lived in humid subtropical forests bathed by rivers and shallow lakes. Its neck, which could reach more than 9 meters in length, was supported by highly pneumatized cervical vertebrae with a honeycomb-like internal structure that reduced weight without compromising strength.

Jurassic Herbivore 22m

AR · 97–93 Ma

Mapusaurus roseae

"Earth lizard (of the rose-colored rocks)"

Mapusaurus roseae was one of the largest terrestrial predators of the Late Cretaceous, inhabiting what is now Argentine Patagonia approximately 97 to 93 million years ago. A member of Carcharodontosauridae, this giant theropod reached 10 to 13 meters in length and weighed between 3 and 6 tonnes. Its skull was deeper and narrower than that of its close relative Giganotosaurus, with characteristic rugose nasals. The discovery of a bonebed containing at least seven to nine individuals of varying ages in the Huincul Formation led researchers to suggest Mapusaurus may have lived and hunted in groups, possibly cooperating to bring down giant prey such as Argentinosaurus.

Cretáceous Carnivore 11m

🇧🇷 BR

BR · 85–80 Ma

Maxakalisaurus

Maxakalisaurus topai

"Maxakali people's lizard, of Topá"

Maxakalisaurus topai is a Brazilian titanosaur discovered in the Adamantina Formation, in the Triângulo Mineiro region of Minas Gerais. Described by Kellner et al. in 2006, it is one of the best-documented sauropods from Brazil. About 13 meters long and estimated to weigh 5 tonnes, it had a long neck and tail, ridged teeth (unusual among sauropods), and osteoderms, bony dermal plates. Its name honors the Maxakali indigenous people from the region, and the deity Topá of the Maxakali pantheon. The holotype (MN 5013-V) was on display at the National Museum of Rio de Janeiro until the 2018 fire, which destroyed part of the material. A reconstruction campaign was subsequently launched to restore the skeleton.

Cretáceous Herbivore 13m

AR · 93–88 Ma

Megaraptor

Megaraptor namunhuaiquii

"Giant thief of Namunhuaiqui"

Megaraptor namunhuaiquii was a large-bodied theropod of the mid-to-late Cretaceous (Turonian-Coniacian, ~93-88 Ma) found in the Portezuelo Formation of Neuquén, Argentina. Estimated at ~8 meters long and about 1000 kg, Megaraptor was one of the largest predators of its time in South America. The most notable feature — and the one that generated decades of taxonomic debate — is its manual claw: an extraordinarily developed sickle-shaped claw on the first finger of the hand, over 30 cm long, which initially led researchers to interpret the animal as a giant dromaeosaurid (with the claw on the foot), before its true position as a megaraptorid was clarified. The specific name namunhuaiquii refers to Namunhualqui hill, a locality near the discovery site in Neuquén.

Cretáceous Carnivore 8m

CN · 125–120 Ma

Microraptor gui

"Small thief of Gui"

Microraptor gui is one of the most extraordinary dinosaurs ever discovered: a four-winged dromaeosaurid approximately 77 centimeters long and weighing about 1 kilogram, living in what is now Liaoning, China, between 125 and 120 million years ago. Its body was covered in aerodynamically preserved feathers in remarkable detail, including long flight feathers on the hindlimbs as well as the forelimbs. The plumage was iridescent black, similar to that of a modern starling. It is considered fundamental evidence in the debate about the origin of avian flight, demonstrating that the four-surface aerodynamic configuration predated modern birds and was functional in the Early Cretaceous.

Cretáceous Carnivore 0.77m

AU · 119–113 Ma

Minmi paravertebra

"From Minmi, with lateral vertebrae (paravertebrae)"

Minmi paravertebra was a small ankylosaur from the Early Cretaceous of Australia, only 3 meters long and weighing around 300 kg. Its most distinctive feature is the paravertebrae: horizontally oriented ossified plates running along the sides of the vertebrae, a structure unique among armored dinosaurs. It was the first thyreophoran discovered in the Southern Hemisphere. A remarkable specimen preserved intact stomach contents, including plant fragments, seeds, and angiosperm fruits, offering a rare window into the diet and ecology of these animals over 110 million years ago.

Cretáceous Herbivore 3m

CN · 166–161 Ma

Monolophosaurus jiangi

"Single-crested lizard (of Jiang)"

Monolophosaurus jiangi was a Middle Jurassic tetanuran theropod that lived in what is now Xinjiang Province, northwestern China, approximately 166 to 161 million years ago. At roughly 5 to 5.5 meters long and 475 kg, it was a medium-sized predator distinguished by a large, single cranial crest running along the midline of the snout, formed by the nasal and premaxillary bones. This pneumatized structure was its most remarkable feature, likely used for visual recognition among members of its own species. Known from a single nearly complete holotype, it preserves one of the best-known basal tetanuran skulls in science.

Jurassic Carnivore 5.5m

AR · 221–205 Ma

Mussaurus

Mussaurus patagonicus

"Mouse lizard from Patagonia"

Mussaurus patagonicus is a Late Triassic sauropodomorph that stars in one of paleontology's most unusual stories: it was named the 'mouse lizard' because the first discovered specimens were tiny hatchlings only 20 centimeters long, small enough to fit in the palm of a hand. When José Bonaparte and Martín Vince described the species in 1979, based on these hatchlings from the Los Colorados Formation of Argentine Patagonia, they imagined a modestly sized adult. Decades later, when adult specimens were found and described in detail, it was revealed that Mussaurus grew to 6 meters in length and 1.5 tonnes: one of the largest terrestrial animals of the Late Triassic in South America. This discrepancy between hatchlings and adults is biologically significant. It demonstrates that basal sauropodomorphs underwent dramatic ontogenetic changes not only in size but also in locomotor posture. Mussaurus hatchlings were facultative bipeds, with proportionally similar fore and hind limbs, while adults had more robust forelimbs and likely transitioned to a quadrupedal posture upon reaching large sizes. This pattern echoes what later became obligatory in the giant sauropods of the Jurassic and Cretaceous. The most impactful publication on Mussaurus in recent years was the 2021 study by Otero et al. published in Scientific Reports. Analysis of multiple nests with eggs, neonatal hatchlings, and spatially grouped juveniles revealed strong evidence of gregarious behavior: the animals gathered in age-segregated groups, suggesting some form of parental care or structured social behavior. Mussaurus eggs were preserved in communal nests at a depth suggesting they were buried for incubation, similar to the behavior of crocodiles and some extant birds. This finding pushes the origin of gregarious behavior in sauropodomorphs back to the Triassic, more than 50 million years earlier than previously thought. Phylogenetically, Mussaurus occupies a key position in the transition between solitary basal sauropodomorphs and the large gregarious sauropods of the Mesozoic. The most recent analyses place it within Massopoda, near the base of the clade that will give rise to true Sauropoda. Its body still preserves plesiomorphic features such as a moderately long neck, more robust hind limbs than forelimbs, and simple leaf-shaped teeth, but already shows derived features such as elongated cervical vertebrae and a sauropod-like tarsal formula. The exceptional fossil record of the Los Colorados Formation, with multiple age classes preserved together, makes Mussaurus the most important Triassic sauropodomorph for studies of growth, ontogeny, and social behavior.

Triassic Herbivore 6m

AU · 112–100 Ma

Muttaburrasaurus langdoni

"Muttaburra lizard (of Langdon)"

Muttaburrasaurus langdoni was a large herbivorous ornithopod that inhabited eastern Australia during the Early Cretaceous, approximately 112 to 100 million years ago. About 8 meters long and weighing 2.8 tonnes, it was one of Australia's largest dinosaurs. Its most distinctive feature was a hollow, inflatable nasal projection, the bulla nasalis, probably used for vocalizations or display. Its teeth were powerful with shearing edges, adapted for cutting through tough vegetation such as ferns and cycads. It is one of the most complete Australian dinosaurs ever found, with approximately 60% of the skeleton preserved, and became the official fossil emblem of Queensland state in 2022.

Cretáceous Herbivore 8m

US · 68–66 Ma

Nanotyrannus lancensis

"Dwarf tyrant of Lance"

Nanotyrannus lancensis is one of the most controversial dinosaurs in paleontology. Originally described by Charles Gilmore in 1946 as a species of Gorgosaurus, it was reclassified as its own genus by Bakker, Williams, and Currie in 1988. The central debate is whether the known specimens represent a distinct small-bodied tyrannosaurid species or juvenile Tyrannosaurus rex individuals. The 'Jane' specimen (BMRP 2002.4.1), found in Montana in 2001 and housed at the Burpee Museum of Natural History, is the most complete ever attributed to the genus. Recent studies by Longrich and Saitta (2024) and Zanno and Napoli (2025) support its taxonomic validity based on bone histology, skeletal proportions, and independent phylogenetic analysis, though the scientific debate remains active.

Cretáceous Carnivore 5.5m

GB · 130–125 Ma

Neovenator salerii

"New hunter of Salero"

Neovenator salerii was the largest land predator in Europe during the Early Cretaceous, approximately 125 million years ago. Discovered on the Isle of Wight, southern England, it reached 7 to 7.5 meters in length and weighed approximately one metric ton. It is the most complete large theropod known from Europe, with about 70% of the skeleton preserved. As a basal member of Neovenatoridae, a group that includes the enigmatic megaraptors, Neovenator possessed a snout with a complex neurovascular network, indicating high facial sensitivity, possibly used in prey detection.

Cretáceous Carnivore 7.5m

NE · 115–105 Ma

The Cretaceous vacuum cleaner

Nigersaurus taqueti

"Taquet's Niger lizard"

Nigersaurus taqueti was a rebbachisaurid sauropod from the Middle Cretaceous, discovered in the Elrhaz Formation of Niger in the Sahara. At about 9 meters long and 4 tonnes, it was small by sauropod standards. Its most striking feature was a wide, flat mouth directed straight downward, packed with over 500 replaceable teeth arranged in dental batteries. This extraordinary anatomy allowed it to graze low vegetation with maximum efficiency, like a Cretaceous lawnmower. Formally described by Paul Sereno in 1999, Nigersaurus became one of the most anatomically peculiar dinosaurs ever discovered.

Cretáceous Herbivore 9m

CA · 76–66 Ma

Ornithomimus

Ornithomimus edmontonicus

"Edmonton bird mimic"

Ornithomimus edmontonicus was a Late Cretaceous ornithomimosaur (Maastrichtian, ~76-66 Ma) that inhabited the coastal plains of western North America, in the region corresponding to today's Alberta (Canada) and adjacent US states. About 3.8 meters long and 170 kg, it possessed the morphology that gave the group its name: a toothless horny beak, long flexible neck, long agile hindlimbs, relatively long arms with non-specialized claws, and a rigid tail for balance. This combination is remarkably convergent with modern ostriches (Struthio camelus), which is why ornithomimosaurs are often called 'ostrich dinosaurs'. Ornithomimus edmontonicus is the best-known and most complete species of the genus, with multiple specimens preserved in the Horseshoe Canyon and Hell Creek formations.

Cretáceous Omnivore 3.8m

NE · 125–112 Ma

Ouranosaurus nigeriensis

"Brave lizard from Niger"

Ouranosaurus nigeriensis is one of the most distinctive ornithopods of the Early Cretaceous, famous for its dorsal crest formed by extraordinarily elongated neural spines. It lived approximately 125 to 112 million years ago in the region that now corresponds to Niger, on a warm and humid fluvial floodplain. About 8 meters long and over 2 tonnes, it was a robust herbivore equipped with battery teeth and a uniquely low and elongated skull among iguanodontids. Described by French paleontologist Philippe Taquet in 1976 based on two nearly complete skeletons, it is considered a close relative of hadrosaurs.

Cretáceous Herbivore 8m

MN · 75–71 Ma

Oviraptor philoceratops

"Egg thief that loves ceratopsians"

Oviraptor philoceratops is one of the most misunderstood dinosaurs in paleontological history. Described by Henry Fairfield Osborn in 1924 from fossils found in the Djadochta Formation of Mongolia, its name means 'egg thief that loves ceratopsians' — an unjust accusation: the animal was actually a devoted parent, brooding its own eggs when it was surprised and buried by a sandstorm 75 million years ago. Around 2 meters long, with a toothless beak, a bony crest on the skull similar to a cassowary, and a feathered body, this agile omnivore inhabited the semiarid forests of the Gobi Desert during the Campanian.

Cretáceous Omnivore 2m

🇧🇷 BR

BR · 100.5–93.9 Ma

Oxalaia

Oxalaia quilombensis

"Oxalaia: deity of the waters in Afro-Brazilian religion; quilombensis: from the quilombos of Maranhão"

Oxalaia quilombensis was one of the largest predators of the Late Cretaceous of South America, with an estimated length of 12 to 14 meters. A member of the family Spinosauridae and subfamily Spinosaurinae, it was closely related to the African Spinosaurus aegyptiacus. Known only from jaw fragments collected on Cajual Island, Maranhão, it possessed conical teeth without serrations, a sculptured secondary palate, and a rosette-shaped anterior snout expansion. Its name honors the deity of the waters in Afro-Brazilian religion and the historical quilombos of Maranhão, acknowledging the cultural heritage of the region where it was discovered.

Cretáceous Piscivore 13m

US · 70–66 Ma

Pachycephalosaurus

Pachycephalosaurus wyomingensis

"Thick-headed lizard from Wyoming"

Pachycephalosaurus wyomingensis is the largest and most famous of the pachycephalosaurids, a group of bipedal ornithischian dinosaurs known for the thick bony dome atop their skull. It lived at the end of the Cretaceous, 70 to 66 million years ago, on the coastal plains and angiosperm forests of what is now Montana, Wyoming, South Dakota, and Alberta. Its frontoparietal dome could reach 25 centimeters in thickness, composed of dense fibrolamellar bone. Studies have revealed that Dracorex hogwartsia and Stygimoloch spinifer were actually juvenile forms of the same species. The dome likely functioned in intraspecific combat, similar to modern bighorn sheep.

Cretáceous Herbivore 4.5m

CA · 73–69 Ma

Pachyrhinosaurus canadensis

"Thick-nosed lizard of Canada"

Pachyrhinosaurus canadensis is a Late Cretaceous ceratopsian that broke the rules of its group: instead of a nasal horn, it bore an enormous flattened bony mass called a boss over its nose and eyes. Discovered in the Horseshoe Canyon Formation of Alberta, Canada, and described by Charles Mortram Sternberg in 1950, the animal measured 6 to 8 meters and weighed approximately 3.5 tons. Its enormous bonebeds, containing hundreds of accumulated bones, suggest gregarious behavior in large herds, making it one of the ceratopsians with the strongest evidence for collective social life.

Cretáceous Herbivore 7m

CA · 76.5–73 Ma

Parasaurolophus

Parasaurolophus walkeri

"Lizard with a crest parallel to Saurolophus (walkeri species)"

Parasaurolophus walkeri is one of the most recognizable dinosaurs of the Late Cretaceous, famous for the extraordinary hollow tubular crest that projected backward from the skull, potentially exceeding one meter in length. A social herbivore with compact rows of hundreds of replacement teeth, it lived in herds on the coastal plains of North America approximately 75 million years ago. The crest likely functioned as an acoustic resonating chamber, enabling low-frequency vocalizations for intraspecific communication. Facultatively bipedal, it alternated between upright stance and four-legged locomotion.

Cretáceous Herbivore 9.5m

AR · 102–100 Ma

Patagotitan

Patagotitan mayorum

"Titan of Patagonia of Mayo (honoring the Mayo family, owners of the farm where it was discovered)"

Patagotitan mayorum is one of the largest land animals that ever existed, a colossal titanosaur discovered in 2010 in Argentine Patagonia. With estimates of up to 37 meters in length and 69 tonnes in weight, it rivaled or surpassed Argentinosaurus for the title of largest dinosaur of all time. Six partial skeletons were excavated between 2013 and 2015 from the Cerro Barcino Formation in Chubut, providing one of the most complete fossil records of a giant titanosaur. Formally described by Carballido et al. in 2017, the animal belongs to the clade Lognkosauria and lived approximately 101 million years ago.

Cretáceous Herbivore 37m

DE · 214–204 Ma

Plateosaurus engelhardti

"Engelhardt's flat lizard"

Plateosaurus engelhardti is the most abundant dinosaur of the European Triassic and one of the earliest large herbivores in dinosaur history. Described by Hermann von Meyer in 1837, it is known from hundreds of specimens collected in Germany, Switzerland, and France, making it one of the best-documented species in the fossil record. Up to 10 meters long and over 4 tonnes, it was an obligate biped, unable to use its hands for quadrupedal locomotion. Its bone histology revealed a unique growth pattern: individuals of the same species could reach very different body sizes depending on environmental conditions, a phenomenon called developmental plasticity.

Triassic Herbivore 8m

MN · 75–71 Ma

Protoceratops

Protoceratops andrewsi

"First horned face (of Andrews)"

Protoceratops andrewsi was a small quadrupedal ceratopsian that lived in the deserts of Central Asia during the Campanian, between 75 and 71 million years ago. About 1.8 meters long and 180 kg, it had a powerful horned beak, a prominent parieto-squamosal frill, and lacked true horns unlike its later relatives. Extraordinarily abundant in the Djadochta Formation, it is known from dozens of specimens at all growth stages from hatchlings to adults, making it one of the most studied dinosaurs in terms of ontogeny. Its fame extends beyond science thanks to the famous Fighting Dinosaurs fossil, in which it appears locked in combat with Velociraptor mongoliensis.

Cretáceous Herbivore 1.8m

MN · 125–100 Ma

Psittacosaurus mongoliensis

"Mongolian parrot lizard"

Psittacosaurus mongoliensis is one of the most primitive known ceratopsians and simultaneously the dinosaur represented by the greatest number of individual specimens in the world. It lived during the Early Cretaceous, between 125 and 100 million years ago, in Central Asia. Roughly two meters long and up to 20 kg, it was relatively small: hatchlings were born under 13 cm in length. Its most distinctive feature is the curved, parrot-like horny beak that gave it its name. Rigid bristles on the tail and scales preserved in exceptional specimens provide unique insights into the actual appearance of dinosaurs.

Cretáceous Herbivore 2m

🇧🇷 BR

BR · 75–70 Ma

Pycnonemosaurus nevesi

"Neves's dense forest lizard"

Pycnonemosaurus nevesi was the largest known abelisaurid dinosaur, estimated at 8.9 meters in length and approximately 3.6 metric tons. It lived during the Late Cretaceous, roughly 70 to 75 million years ago, in what is now Mato Grosso State, Brazil. Described by Kellner and Campos in 2002, it was the first confirmed abelisaurid from the Bauru Group. It belongs to the Furileusauria lineage of South American abelisaurids, the same group that includes Carnotaurus and Aucasaurus. Its fragmentary fossils reveal a large predator that likely preyed on titanosaur sauropods sharing its environment.

Cretáceous Carnivore 8.9m

US · 68–66 Ma

Quetzalcoatlus northropi

"Northrop's feathered sky serpent (honoring the Aztec sky god Quetzalcóatl and aircraft designer Jack Northrop)"

Quetzalcoatlus northropi is the largest known pterosaur and one of the largest flying animals in Earth's history. With a wingspan estimated at 10 to 11 meters, it was as wide as a single-engine aircraft. It lived during the late Maastrichtian, 68 to 66 million years ago, in the Javelina Formation of Texas, in the basin of what is now Big Bend National Park. Despite its colossal size, it weighed only 150 to 250 kg thanks to hollow bones reinforced with internal struts. Biomechanical studies show it was capable of active flight, taking off with a quadrupedal vault using its forelimbs. On land, it walked quadrupedally and hunted small vertebrates in the manner of a giant stork.

Cretáceous Carnivore 5m

IN · 69–66 Ma

Rajasaurus narmadensis

"Regal lizard from the Narmada"

Rajasaurus narmadensis was the apex terrestrial predator of the Indian subcontinent during the Late Cretaceous. It lived between 69 and 66 million years ago in what is now Gujarat state, northwestern India, in an arid-to-semi-arid environment crossed by seasonal rivers and punctuated by the volcanic episodes of the Deccan Traps. The only Indian abelisaurid with well-preserved postcranial remains, it was distinguished by a median sagittal crest atop the skull, unique among Indian abelisaurids. Its placement within Majungasaurinae confirms the biogeographic connection between India and Madagascar in the Late Cretaceous.

Cretáceous Carnivore 6.6m

NE · 99–93 Ma

Rugops primus

"First wrinkle face"

Rugops primus is a basal abelisaurid from the Late Cretaceous, discovered in the Echkar Formation of Niger, at the heart of the Sahara Desert. It lived approximately 95 million years ago, during a period when Gondwana was still fragmenting. Its partial skull, roughly 31 centimeters long, features a surface covered with vascular foramina and depressions on the nasal bones — unique structures that likely supported crests, cornified scales, or dermal ornaments in life. Its relatively small teeth led some researchers to propose scavenging behavior, though this hypothesis remains debated. As one of the first well-documented African abelisaurids, Rugops provided key evidence for faunal connections between Gondwanan landmasses during the mid-Cretaceous.

Cretáceous Carnivore 6m

AR · 70–66 Ma

Saltasaurus

Saltasaurus loricatus

"Lizard from Salta, protected by armored plates"

Saltasaurus loricatus is an Upper Cretaceous titanosaur from Argentina and one of the most important sauropods in South American paleontology. Described by Bonaparte and Powell in 1980 from fossils of the Lecho Formation in Salta Province, it was the first sauropod confirmed with dermal armor: oval-plate osteoderms and rounded ossicles covering the back. With a relatively short neck and robust limbs, it inhabited fluvial-lacustrine plains. Mass nesting evidence at Auca Mahuevo, from closely related saltasaurines, suggests gregarious reproductive behavior for the group.

Cretáceous Herbivore 9m

US · 115–108 Ma

Sauropelta edwardsorum

"Edwards's lizard shield"

Sauropelta edwardsorum was one of the largest nodosaurids of the Early Cretaceous in North America. Measuring approximately 5.2 to 6 meters in length and weighing up to 2 metric tons, it was a heavily armored herbivore from the Cloverly Formation of present-day Wyoming and Montana. Its most distinctive feature was a row of enormous lateral spines along its neck and shoulders that increased progressively in size toward the torso. Unlike ankylosaurids, it lacked a tail club, but its body was densely covered with osteoderms. The long tail, composed of more than fifty vertebrae, accounted for nearly half the animal's total length. Described by John Ostrom in 1970, it is considered one of the best-understood nodosaurids in science.

Cretáceous Herbivore 5.5m

GB · 196–183 Ma

Scelidosaurus

Scelidosaurus harrisonii

"Limb lizard"

Scelidosaurus harrisonii is one of the oldest and most complete armored dinosaurs known to science. It lived during the Early Jurassic, approximately 196 to 183 million years ago, along the shores of what is now southwestern England. Roughly 4 meters long and 270 kg, it was a quadrupedal herbivore covered by horizontal rows of oval osteoderms along its neck, back, and tail. Its skull bore horny scutes, occipital horns, and unique bony structures found in no other dinosaur. Originally described by Richard Owen in 1861, Scelidosaurus holds a key position in the evolution of thyreophoran dinosaurs, ancestral to the ankylosaurs.

Jurassic Herbivore 4m

IT · 115–110 Ma

Ciro

Scipionyx samniticus

"Scipio's claw of the Samnites"

Scipionyx samniticus is the only Italian dinosaur with preserved internal organs, earning it the affectionate nickname 'Ciro'. Discovered in 1981 near Pietraroja, in Campania, the only known specimen is a juvenile just 24 centimeters long, fossilized about 113 million years ago in limestone from a shallow lagoon. The three-dimensional preservation of intestine, trachea, liver, and muscle tissues through calcium phosphatization is unprecedented among dinosaurs. Estimated adults would have reached about 2 meters in length. Its phylogenetic placement within Compsognathidae is accepted by most researchers, though debate persists because the specimen is a neonate.

Cretáceous Carnivore 2m

CN · 125–122 Ma

Sinosauropteryx prima

"First Chinese reptile wing"

Sinosauropteryx prima is one of the most revolutionary dinosaurs in the history of paleontology. Discovered in 1996 in the Yixian Formation of Liaoning, China, it was the first confirmed non-avian dinosaur with feather-like structures. At only 1.07 meters long and less than 600 grams, it was an agile predator of small lizards and mammals. In 2010, it became the first dinosaur to have its true colors scientifically confirmed: ginger and white stripes on the tail and a dark mask around the eyes, revealed through analysis of fossilized melanosomes.

Cretáceous Carnivore 1.07m

EG · 99–93 Ma

Spinosaurus

Spinosaurus aegyptiacus

"Egyptian spine lizard"

Spinosaurus aegyptiacus was the largest theropod ever recorded, surpassing Tyrannosaurus rex in length. At up to 15 meters and an estimated mass between 6,000 and 7,400 kg, it dominated the river systems of northern Africa during the Cenomanian (99 to 93 million years ago). Its most striking feature was the dorsal sail supported by neural spines up to 1.65 meters tall, whose function is still debated: thermoregulation, sexual display, or fat storage. The snout was elongated and narrow, with conical teeth adapted for catching fish, resembling the morphology of modern crocodilians. Pressure receptors in the snout, similar to those in crocodiles, allowed it to detect prey underwater. In 2020, Ibrahim and colleagues described a paddle-like tail with tall neural spines and expanded chevrons, confirming adaptations for propulsive swimming. Spinosaurus is the only non-avian dinosaur with robust evidence of aquatic habits. The original fossils, collected by Markgraf in Egypt in 1912, were destroyed in the Allied bombing of the Munich Museum in 1944, making rediscoveries in Morocco essential for reconstructing the animal.

Cretáceous Piscivore 15m

🇧🇷 BR

BR · 233–225 Ma

Staurikosaurus pricei

"Southern Cross lizard, honoring Llewellyn Ivor Price"

Staurikosaurus pricei is one of the most primitive carnivores known, living approximately 233 to 225 million years ago in what is now Rio Grande do Sul, Brazil. At roughly 2.1 meters long and 30 kilograms, it was a medium-sized bipedal predator for its time. Its serrated, backward-curving teeth indicate an active carnivorous diet. Described by Edwin Colbert in 1970 from holotype MCZ 1669, its phylogenetic position remains debated: sometimes classified in Herrerasauridae, sometimes as an even more basal dinosaur. It is one of the most important animals for understanding the earliest stages of dinosaur evolution.

Triassic Carnivore 2.1m

US · 155–150 Ma

Stegosaurus

Stegosaurus armatus

"Armored roof lizard"

Stegosaurus armatus is one of the most recognizable dinosaurs of the Jurassic, famous for its two alternating rows of dorsal bony plates and four tail spikes, the so-called thagomizer. It lived approximately 155 to 150 million years ago in the Morrison Formation of the western United States. Up to 9 meters long and weighing around 5,400 kg, it was a large herbivore that browsed low vegetation with small teeth and a horny beak. Its brain was proportionally tiny, roughly 80 grams. The dorsal plates, sheathed in keratin, were likely used for visual recognition between individuals and possibly for thermoregulation. Fóssil evidence confirms the thagomizer was an effective defensive weapon: an Allosaurus vertebra was found with a puncture matching Stegosaurus spike dimensions, with healed bone around the wound.

Jurassic Herbivore 9m

CA · 75.5–74.5 Ma

Styracosaurus albertensis

"Spiked lizard of Alberta"

Styracosaurus albertensis was a centrosaurine ceratopsid that lived during the Late Campanian stage of the Cretaceous, approximately 75 million years ago, in what is now the province of Alberta, Canada. Measuring roughly 5.5 meters in length and weighing about 2.7 metric tons, it was distinguished by an elaborately ornamented skull featuring a nasal horn up to 60 centimeters long and a parietal frill bearing up to six long posterior spikes. These structures likely functioned in intraspecific recognition and mate attraction. Large fossil accumulations suggest the animals lived in herds and may have migrated seasonally across Campanian coastal environments.

Cretáceous Herbivore 5.5m

NE · 125–112 Ma

Suchomimus tenerensis

"Crocodile mimic from Ténéré"

Suchomimus tenerensis was a giant spinosaurid of the Early Cretaceous, reaching around 10 to 11 meters in length and up to 3.5 metric tons. Its elongated, narrow snout resembling a crocodile's, and its row of conical teeth adapted for gripping slippery fish, made it a specialized piscivore. The large curved thumb claws, up to 19 centimeters long, were its primary weapons for hooking aquatic prey. It lived on tropical floodplains in what is now Niger, coexisting with the giant crocodyliform Sarcosuchus and sauropods such as Nigersaurus. It was described in 1998 by Paul Sereno and colleagues from fossils found in the Ténéré Desert.

Cretáceous Piscivore 10.5m

US · 153–150 Ma

Supersaurus

Supersaurus vivianae

"Super lizard"

Supersaurus vivianae is one of the longest dinosaurs ever discovered, with estimates ranging between 33 and 40 meters in length. A diplodocid sauropod of the Late Jurassic, it lived in the ecosystems of the Morrison Formation in western North America approximately 153 to 150 million years ago. Its extremely long neck, supported by specialized cervical vertebrae, allowed it to reach vegetation over large areas without moving its body. The longest known cervical vertebra measures 1.38 meters. With an estimated mass of 35 to 44 tonnes, it combined colossal size with efficient ossification, thanks to an air sac system similar to that of birds.

Jurassic Herbivore 33m

MN · 72–66 Ma

Tarbosaurus

Tarbosaurus bataar

"Alarming lizard (from Greek tarbos = alarm, terror + sauros = lizard). The epithet bataar comes from Mongolian баатар, meaning hero or warrior."

Tarbosaurus bataar was the largest land predator in Asia at the end of the Cretaceous, 72 to 66 million years ago. At up to 10 to 12 meters long and around 5 metric tons, it was the Asian equivalent of Tyrannosaurus rex, with whom it shared close kinship within the subfamily Tyrannosaurinae. Its skull measured approximately 1.3 meters, proportionally narrower than that of T. rex, with more laterally oriented orbits resulting in a reduced binocular field. The forelimbs were proportionally even smaller than those of T. rex, with only two functional digits. Known from over 30 specimens, including more than 15 skulls and several complete postcranial skeletons, Tarbosaurus is one of the best-represented tyrannosaurids in the fossil record. Its remains come exclusively from the Nemegt Formation of Mongolia and the Subashi Formation of China.

Cretáceous Carnivore 10m

US · 115–108 Ma

Tenontosaurus

Tenontosaurus tilletti

"Tillett's sinew lizard"

Tenontosaurus tilletti was a medium-sized iguanodontian ornithopod that lived during the Aptian-Albian of the Early Cretaceous, approximately 115 to 108 million years ago, in what is now the western United States. At 6 to 7.5 meters in length and estimated body mass of 700 to 1,000 kg, it was one of the most common and abundant herbivores of its time and region. The genus is morphologically distinct from other ornithopods by its extraordinarily long and robust tail, which in adults could represent more than half the total length of the animal. The caudal vertebrae are reinforced by ossified tendons, hence the name 'sinew lizard', which provided rigidity to the tail and possibly functioned as a counterweight to maintain balance during bipedal or quadrupedal locomotion. Tenontosaurus was capable of moving both on two and four legs depending on speed and terrain. The paleontological importance of Tenontosaurus extends far beyond its intrinsic morphology: the animal is the center of the longest and most influential debate in paleontology about cooperative predatory behavior in dinosaurs. When John Ostrom described Deinonychus antirrhopus in 1969 and 1970, he based much of his argument about pack hunting on the recurring spatial association of multiple Deinonychus teeth with Tenontosaurus carcasses in the Cloverly Formation. Ostrom inferred that groups of Deinonychus cooperatively attacked much larger Tenontosaurus individuals, similarly to the behavior of modern lions. This hypothesis became enormously influential and directly inspired the representation of Velociraptors as cooperative hunters in Jurassic Park (1993). However, subsequent analyses questioned the cooperative hunting interpretation. Roach and Brinkman (2007) argued that the association of Deinonychus with Tenontosaurus carcasses is more consistent with competitive scavenging behavior, like that observed in modern Komodo dragons feeding on the same carcass without true cooperation and frequently attacking each other during the feast. Evidence of multiple dead Deinonychus at the same localities as Tenontosaurus would suggest Tenontosaurus was capable of actively defending itself, killing some of its attackers. This debate about cooperative hunting versus competitive feeding in Deinonychus, centered on Tenontosaurus carcasses, remains without definitive resolution and continues to be one of the most stimulating problems in dinosaur behavior.

Cretáceous Herbivore 6.5m

MN · 76–69 Ma

Therizinosaurus

Therizinosaurus cheloniformis

"Reaping lizard with turtle-like form"

Therizinosaurus cheloniformis is one of the most bizarre dinosaurs ever discovered. It was a herbivorous theropod that lived during the Late Cretaceous, approximately 70 million years ago, in present-day Mongolia. Reaching up to 10 meters in length and weighing around 5 tonnes, its most striking feature was the enormous claws on its forelimbs, which could reach 70 cm in length, the largest of any known animal. Despite belonging to the same group as velociraptors and T. rex (Theropoda), Therizinosaurus was herbivorous, using its claws to pull down branches and feed on foliage. It was initially described as a giant turtle by Evgeny Maleev in 1954, and it took decades before paleontologists understood its true nature as a theropod dinosaur.

Cretáceous Herbivore 10m

US · 68–66 Ma

Torosaurus

Torosaurus latus

"Broad perforated lizard"

Torosaurus latus is one of the most imposing ceratopsids of the Late Cretaceous, notable for possessing the largest skull of any known land animal, reaching up to 2.77 meters in length. It lived between 68 and 66 million years ago in the Hell Creek and Lance Formations of western North America. Approximately 8 to 9 meters long and weighing up to 8 tonnes, it was a contemporary of Triceratops and Tyrannosaurus rex. Its extremely elongated frill bears two large bony openings (parietal fenestrae), a feature clearly distinguishing it from Triceratops. Described by Othniel Charles Marsh in 1891, Torosaurus sparked one of the most intense controversies in recent paleontology when Scannella and Horner (2010) proposed that its specimens were simply old Triceratops. Later studies, including bone histology analysis, refuted this hypothesis.

Cretáceous Herbivore 8.5m

US · 68–66 Ma

Triceratops

Triceratops horridus

"Horrible three-horned face"

Triceratops horridus is one of the most recognizable dinosaurs of the Late Cretáceous, famous for its three facial horns and large bony neck frill. It lived between 68 and 66 million years ago in the Lance and Hell Creek Formations of the western United States. Up to 9 meters long and weighing up to 12 tonnes, it was one of the largest herbivores in its ecosystem. The skull could exceed 2.5 meters in length, ranking among the largest of any terrestrial animal. Its dental battery included 36 to 40 tooth columns per jaw side, enabling processing of large volumes of fibrous plant material. The horns and frill were likely used primarily for species recognition, sexual display, and dominance among individuals, with possible secondary use in defense against Tyrannosaurus rex.

Cretáceous Herbivore 9m

US · 77–74 Ma

Troodon formosus

"Wounding tooth (from Greek troodos = to wound + odon = tooth; formosus = beautiful in Latin)"

Troodon formosus was a small theropod from the Late Cretaceous of North America, notable for possessing the largest brain relative to body size among all known non-avian dinosaurs. At approximately 2.4 meters long and 45 kg, it inhabited the seasonal forests of the Two Medicine Formation in Montana. Its large, forward-facing eyes suggest binocular vision and possible nocturnal activity. Teeth with apical serrations indicate an omnivorous diet, including small mammals and possibly plant material. Originally described by Joseph Leidy in 1856 from a single tooth, Troodon became a symbol of the debate on intelligence and behavior in dinosaurs.

Cretáceous Omnivore 2.4m

CN · 77–73 Ma

Tsintaosaurus spinorhinus

"Tsingtao lizard with nasal spine"

Tsintaosaurus spinorhinus was a Campanian hadrosaurid from China, described by Yang Zhongjian in 1958 based on fossils collected at Laiyang, Shandong. Approximately 8.3 meters long and weighing 2.5 tonnes, it was a large herbivore that moved between bipedal and quadrupedal postures. Its most distinctive feature is the nasal crest: long described as a vertical unicorn-like spike, a 2013 analysis by Prieto-Márquez and Wagner revealed it to be the rear portion of a broader, lobate cranial structure formed by the nasal and premaxillary bones. The crest likely functioned in species recognition and acoustic communication within the herd.

Cretáceous Herbivore 8.3m

US · 68–66 Ma

T-Rex

Tyrannosaurus rex

"King of the tyrant lizards"

Tyrannosaurus rex is arguably the most famous dinosaur in the world. It lived at the end of the Cretáceous period, 68 to 66 million years ago, in what is now North America. At up to 12 meters long and over 8 metric tons, it was the apex predator of its ecosystem. Its serrated teeth measured up to 20 centimeters. While its tiny arms are often mocked, they were muscular enough to lift up to 200 kg. Recent research suggests T. rex may have had proto-feathers on parts of its body, as seen in close relatives.

Cretáceous Carnivore 12m

US · 126–125 Ma

Utahraptor

Utahraptor ostrommaysorum

"Utah thief of Ostrom and Mays"

Utahraptor ostrommaysorum is the largest known dromaeosaurid, the Early Cretáceous equivalent of a giant velociraptor. Up to 6 meters long and around 500 kg, it was considerably larger than Late Cretáceous dromaeosaurids. It lived 126 to 125 million years ago in the Cedar Mountain Formation of Utah, in an ecosystem dominated by large iguanodonts and ankylosaurs. Its most iconic feature is the retractable sickle claw on the second toe, up to 24 centimeters long, used to pin prey or inflict deep wounds. Like other dromaeosaurids, it was likely covered in feathers, inferred from close relatives with preserved feathers. A sandstone block containing at least seven individuals, including adults, juveniles, and a hatchling, suggests gregarious behavior with some social structure.

Cretáceous Carnivore 6m

MN · 75–71 Ma

Velociraptor

Velociraptor mongoliensis

"Swift thief of Mongolia"

Velociraptor mongoliensis was a small dromaeosaurid dinosaur approximately two meters long and under 20 kg, living during the late Campanian stage of the Cretáceous, 75 to 71 million years ago, in Mongolia. Unlike its depiction in Jurassic Park, it was roughly turkey-sized. It had confirmed feathers, evidenced by quill knobs on the ulna, a sickle-shaped enlarged claw on the second toe, and was likely an agile hunter of small vertebrates in the arid sand-dune environment of the Djadochta Formation.

Cretáceous Carnivore 2.07m

CN · 163–159 Ma

Yi qi

"Strange wings"

Yi qi (pronounced approximately 'ee chee') was a diminutive scansoriopterygid dinosaur that lived during the Middle to Late Jurassic, Oxfordian stage, approximately 163 to 159 million years ago, in the region of present-day Hebei, northern China. At only 0.6 meters in length with an estimated body mass of 380 grams, it was smaller than most modern pigeons. The most extraordinary feature of Yi qi is the styliform elongate bony rod projecting from the wrist: a long, pointed skeletal element that, together with a skin membrane (patagium), formed a wing of morphology entirely unlike any other known flying bird or dinosaur. This combination of a membrane wing supported by an accessory bony rod is unique among Dinosauria and finds functional parallels only in bats and flying squirrels among modern vertebrates. The holotype specimen (STM 31-2) was preserved with impressions of contour feathers on the body and filamentous plumage, plus portions of carbonized wing membrane visible around the forelimbs. Histological analysis of the feathers and bones indicates the animal had not reached full skeletal maturity at death, making adult size estimates slightly uncertain. Yi qi had long recurved foot claws consistent with arboreal habits, and simple conical teeth suggesting insectivorous or generalist carnivorous diet. The skull is relatively large in proportion to the body, with broad orbital openings, suggesting acute vision in a forest canopy environment. The phylogeny of Yi qi within Scansoriopterygidae is well-supported, but the placement of that clade within Coelurosauria remains debated: recent analyses alternate between positioning them as basal members of Pennaraptora or as an independent branch of theropods that developed gliding flight convergently and independently from modern birds. If Yi qi's patagium permitted active flight, it would represent a third independent origin of flight among feathered Jurassic dinosaurs, alongside the lineages leading to modern birds (Avialae) and possibly the gliding of Microraptor. Alternatively, aerodynamic analyses suggest the wing morphology was better suited to descending gliding from elevated perches than to sustained flapping. The discovery was announced in April 2015 in Nature by Xu Xing and collaborators, immediately becoming one of the most impactful paleontological finds of the decade.

Jurassic Carnivore 0.6m

CN · 125–122 Ma

Yutyrannus huali

"Beautiful feathered tyrant"

Yutyrannus huali is the largest feathered animal known in the history of life, measuring around 9 metres in length and weighing approximately 1.4 tonnes. It lived during the Early Cretaceous, some 125 million years ago, in what is now northeastern China. A basal tyrannosauroid of the family Proceratosauridae, it was a distant relative of the famous T. rex but far more primitive. Its filamentous feathers, exceptionally preserved in all three known specimens, reached up to 20 cm in length and covered much of the body, likely aiding thermoregulation in a cold, high-altitude environment. It bore a prominent nasal crest and proportionally longer arms than derived tyrannosaurids.

Cretáceous Carnivore 9m

Mesozoic · Non-dinosaurs

Other Animals of the Mesozoic

Not dinosaurs, but they dominated the oceans, the skies, and parts of the continents during the same period.

Shark · Marine

Hybodus

"Curved tooth"

The most successful shark of the Mesozoic. Had two types of teeth: pointed for fish and flat for crustaceans — rare versatility. Shared the seas with ichthyosaurs, plesiosaurs, and mosasaurs.

Triassic–Cretaceous 2.5m Marine

Shark · Marine

Cretoxyrhina mantelli

"Sharp-snouted of the Cretaceous"

One of the largest sharks of the Cretaceous. Smooth unserrated teeth, high speed, morphology similar to the modern great white. Fossils show mosasaur vertebrae bearing its tooth marks.

Cretaceous 7m Marine

Shark · Marine

Squalicorax

"Raven shark"

Shark with heavily serrated teeth similar to the modern tiger shark. Fossil evidence shows it fed on carcasses of dinosaurs that fell into rivers and seas — the open-ocean scavenger niche.

Cretaceous 5m Marine

Ichthyosaur · Marine

Ichthyosaurs

"Fish lizards"

Extraordinary convergence with dolphins and sharks, but they were reptiles that gave birth to live young at sea. Shonisaurus (Triassic) reached 21m. Ophthalmosaurus had the largest proportional eyes of any known vertebrate.

Triassic–Cretaceous 21m Marine

Plesiosaur · Marine

Plesiosaurs

"Near lizard"

Elasmosaurus had ~14m of neck with 72 cervical vertebrae. They swam with four large flippers in a kind of "underwater flight," snatching individual fish with rapid neck strikes.

Jurassic–Cretaceous 14m Marine

Plesiosaur · Marine

Pliosaurs

"More lizard"

Sister group of plesiosaurs, but with a short neck and enormous head. Kronosaurus had a 2.7m skull. Predator X (Jurassic, Norway) may have reached 15m. Top predators of Jurassic oceans.

Jurassic–Cretaceous 15m Marine

Mosasaur · Marine

Mosasaurus hoffmannii

"Lizard of the Meuse River"

The largest known mosasaur at 17 meters. Related to monitor lizards and snakes, not crocodiles. First giant marine reptile fossil described by science (1764, Maastricht). Had a double-hinged jaw like snakes.

Cretaceous 17m Marine

Pterosaur · Aerial

Pterosaurs

"Winged lizards"

Not dinosaurs — they were the sister group. Had hair-like fibers (pycnofibers) and were likely endothermic. Quetzalcoatlus northropi: 10–11m wingspan, 2.5m tall on land. Largest flying animal of all time.

Triassic–Cretaceous 11m Aerial

Archosaur · Terrestrial

Rauisuchids

"Crocodilians of Rau"

While dinosaurs were still small, rauisuchids were the apex predators of the Triassic. Saurosuchus (7m), Postosuchus (6m), Fasolasuchus (8–10m). Their extinction cleared the way for large theropods.

Triassic 10m Terrestrial

Archosaur · Terrestrial

Phytosaurs

"Plant lizards"

Perfect convergence with modern crocodilians, but no close relation. Key difference: nostrils positioned almost between the eyes (in crocodilians they sit at the tip of the snout).

Triassic 6m Terrestrial

Crocodylomorph · Terrestrial

Crocodyliformes

"Crocodile-shaped"

Far more diverse in the Mesozoic than today: bipedal terrestrial forms in the Triassic, pelagic marine forms in the Jurassic. Dakosaurus had a theropod-like skull. What we know today is just the survivors.

Triassic–Cretaceous 8m Terrestrial

Synapsid · Terrestrial

Dicynodonts

"Two dog teeth"

Synapsids with a horny beak and tusks. Lystrosaurus dominated the early Triassic after surviving the Permian mass extinction. Placerias (hippo-sized) briefly coexisted with the first dinosaurs.

Triassic 3m Terrestrial

Mammal · Terrestrial

Mesozoic mammals

"Mammals of the Age of Dinosaurs"

Small, likely nocturnal, living on the margins. But there was real diversity: Castorocauda (semi-aquatic, 164 Ma), Volaticotherium (glider, 160 Ma), Repenomamus (fossil found with a dinosaur hatchling in its stomach).

Triassic–Cretaceous 1m Terrestrial