Eusauropoda

Eusauropoda is a major clade of Sauropoda, the group of large, long-necked herbivorous dinosaurs. In cladistic terms, Eusauropoda comprises the sauropod lineages descended from a common ancestor that is more closely related to all modern sauropods than to the earliest, more primitive sauropodomorphs outside the group. The clade includes many of the best-known sauropods from the Jurassic and Cretaceous periods, representing a broad range of sizes and forms.

Fossils attributed to eusauropods are found on every continent, with a first appearance dating to the Late Triassic to Early Jurassic. The lineage underwent extensive diversification during the Jurassic, producing numerous genera and a wide array of body plans, many of which were adapted to very large sizes. Several eusauropod lineages persisted into the Cretaceous, contributing to the long evolutionary success of the group.

Characteristic features of eusauropods include a robust, often highly pneumatised skeleton that supports large bodies, long necks in many taxa, and limb bones adapted for bearing substantial weight. The skull is typically small relative to body size, and dentition varies among lineages as they adapted to different feeding strategies within a herbivorous diet.

Within Eusauropoda, a major subdivision is Neosauropoda, which further divides into groups such as Diplodocoidea and Macronaria. Notable representatives include Diplodocus (Diplodocoidea) and Brachiosaurus (Macronaria). Eusauropoda is central to discussions of sauropod evolution and gigantism; however, its exact internal relationships and boundaries have shifted with new analyses, and the concept remains subject to ongoing revision.