Brachiosauridae

The Brachiosauridae ("arm lizards", from Greek brachion (βραχίων) = "arm" and sauros = "lizard") are a family or clade of herbivorous, four-legged sauropod dinosaurs. These huge dinosaurs had long necks. This helped them reach leaves on tall trees that other sauropods could not reach. Their thick, spoon-shaped teeth helped them eat tough plants.

One of the most famous Brachiosaurids is Brachiosaurus. Brachiosaurids lived in places that are now North and South America, Africa, Europe, and Asia. They first appeared during the Late Jurassic period, maybe even earlier, and disappeared in the Late Cretaceous period. Their wide distribution across many continents suggests they lived before the supercontinent Pangaea broke apart.

Brachiosauridae is defined as all titanosauriforms more closely related to Brachiosaurus than to Saltasaurus. They are one of the three main groups in the clade Titanosauriformes, along with the Euhelopodidae and the Titanosauria.

Description

The Brachiosauridae were a group of very large, four-legged dinosaurs. They had thick, spoon-shaped teeth for eating tough plants. Their long necks, with twelve to thirteen long neck bones, let them reach leaves high in trees that other dinosaurs could not.

Brachiosaurids lived in areas with tall conifer trees, which gave them food. Their long necks could bend upward, so they could eat from treetops as high as about 14 metres (46 feet) above the ground. They had longer front legs than hind legs, which gave them a special way of moving, and they could walk faster when they needed to.

History of findings

In 1903, Elmer Samuel Riggs described and named Brachiosaurus. He created a new group called Brachiosauridae in 1904. Since then, how scientists classify these dinosaurs has changed many times. Today, Brachiosauridae is known as a special group within the larger Titanosauriformes.

Important discoveries include the "French Bothriospondylus" found in France in 1943. In 2017, it was identified as Vouivria damparisensis, the oldest known brachiosaurid. Many brachiosaurid species have been named since the late 1990s, helping scientists learn more about this group.

Paleo biogeographic distribution

Brachiosaurids lived from the Late Jurassic to the Early Cretaceous, about 157 to 100 million years ago. We find their fossils in many places, like North America, Africa, Europe, and South America. This tells us they may have lived earlier, in the Middle Jurassic, before the continents moved apart.

In the Early Cretaceous, brachiosaurids were mostly in North America. But new finds in Lebanon and Colombia show they lived in other places too. These discoveries help scientists learn more about where brachiosaurids lived long ago.

Classification

Brachiosauridae is one of the two major clades of Titanosauriformes. This group includes many different kinds of sauropods that lived long ago during the Late Jurassic and Early Cretaceous periods.

Titanosauriformes had some very big and some very small sauropods. There were three main families in this group. Brachiosauridae lived in the Late Jurassic and Early Cretaceous. There were also Euhelopodidae from East Asia, and Titanosauria from Gondwana. Brachiosauridae traditionally included Brachiosaurus, but some scientists now think it might be split into two different species.