Maraapunisaurus

MEANING: Huge lizard

PERIOD: Late Jurassic

CONTINENT: North America

Maraapunisaurus is a sauropod dinosaur known only from a partial vertebra that was described in 1878, and has since been lost. Size estimates vary, but it is thought to be around 35-40 m long, weighing 70-120 t. If the original description is accurate, even conservative estimates place Maraapunisaurus as one of the largest animals ever to walk the earth.

Maraapunisaurus is from the Late Jurassic. The Late Jurassic was a dynamic period, spanning from about 162 to 143 million years ago. The continents were continuing to drift apart, and the supercontinent Pangaea had fully split into Laurasia in the north and Gondwana in the south. This continental rearrangement led to the formation of large inland seas and shallow coastlines that fostered diverse ecosystems. The climate during the Late Jurassic was warm and humid, with lush forests of conifers and ferns that stretched across much of the continents, creating a rich ecosystem where dinosaurs flourished the dominant land animals.

Dinosaurs continued to diversify through the Late Jurassic, with some of the most famous species evolving in this time. Many well-known sauropods, such as Brachiosaurus and Apatosaurus roamed the land, exhibiting niche partitioning with their selectively distinct neck positions. Alongside them, stegosaurs became widespread, their plates and spikes making them one of the era's most recognizable groups. Theropods like Allosaurus and Ceratosaurus were the apex predators, evolving large, powerful bodies and sharp teeth that allowed them to hunt the gigantic herbivores. The early evolution of birds was taking place, setting the stage for the numerous species that would fill the skies in the eras to come.

Unlike the dramatic mass extinctions that marked the beginning and end of the Mesozoic, the Jurassic Period ended without a sharp boundary. As the continents continued to drift, ecosystems gradually transformed into unique habitats that supported the more specialized dinosaur species of the Cretaceous.

Maraapunisaurus is a Rebbachisaurid. Rebbachisauridae is a distinctive group of sauropod dinosaurs within the larger clade Diplodocoidea, known primarily from the Cretaceous. They are characterized by several key anatomical traits, including lighter skeletal construction. Some rebbachisaurids also retained unusual, toothy adaptations such as elongated, spoon-shaped or spatulate teeth confined to the front of the jaws, likely used for cropping vegetation. These feeding adaptations suggest they may have specialized in a different range of plant material than other sauropods of their time.

Rebbachisaurids are best known from the southern hemisphere, particularly South America and Africa, but their fossils have also been found in Europe. This widespread distribution implies they were successful and adaptable herbivores in a variety of Cretaceous environments. Rebbachisaurids were important members of their ecosystems, often among the last surviving diplodocoid lineages before sauropod diversity narrowed to the titanosaurs in the Late Cretaceous.