Sauroposeidon

MEANING: Lizard earthquake god

PERIOD: Early Cretaceous

CONTINENT: North America

Sauroposeidon is a sauropod dinosaur known from several specimens, including fossilized trackways in the United States. The largest known vertebra is 1.4 m long, making it the longest sauropod neck vertebra on record. Sauroposeidon was able to raise its head up to 18 m above the ground, and is estimated around 30 m in length, and 40–60 t in body mass.

Sauroposeidon is from the Early Cretaceous. The Cretaceous is the third and final geological period of the Mesozoic Era, with the Early Cretaceous making up roughly the first half, lasting from about 143 to 100 million years ago. The poles were ice-free, due to the relatively warm climate, and forests extended into high latitudes. The continued breakup of the continents created new coastlines and isolated landmasses, influencing the evolution of distinct dinosaur faunas.

It was a time of transition, as many groups of animals and plants began to take on more modern forms while others declined or disappeared. Pterosaurs continued to thrive, though early birds were becoming more diverse and widespread. Mammals remained small but adapted to a variety of ecological niches. In the oceans, ichthyosaurs and plesiosaurs were common, and early mosasaurs began to appear.

Dinosaurs remained the dominant land animals, with groups like iguanodontians, spinosaurids, and carcharodontosaurids rising to prominence. While sauropods declined in some regions, they remained abundant in the Southern Hemisphere. The first true ceratopsians appeared, and ankylosaurs replaced stegosaurs in their niche. Dromaeosaurs and other small theropods diversified. During this time, the first flowering plants evolved, gradually changing global ecosystems by providing new food sources for herbivores.

Sauroposeidon is a sauropod. Sauropods are saurischian dinosaurs that had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Brachiosaurus, Diplodocus, Apatosaurus and Brontosaurus.

The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic, and by the Late Jurassic (150 million years ago), sauropods had become widespread. By the Late Cretaceous, one group of sauropods, the titanosaurs, had replaced all others and had a near-global distribution. This group included the largest animals ever to walk the earth. Estimates vary, but the largest titanosaurs are estimated at upward of around 40 m, and weighing 100 t, or possibly even more.

As with all other non-avian dinosaurs alive at the time, the titanosaurs died out in the Cretaceous–Paleogene extinction event. Fossilized remains of sauropods have been found on every continent, including Antarctica.