The first specimen of the new sauropod Erketu ellisoni, from the Lower Cretaceous of the eastern Gobi of Dornogov, Mongolia, is described here. The specimen comprises a well-preserved articulated anterior cervical series, an articulated lower hindlimb, and a sternal plate. This sauropod displays a unique combination of features including low, bifid neural spines, elongate cervical centra, and crescent-shaped sternal plates. Computed tomography imaging reveals the vertebrae were extensively invaded with pneumatic camellae. The holotype individual of Erketu was of modest mass relative to other neosauropods, but had an extremely elongate neck. Phylogenetic analysis indicates Erketu is a member of the Somphospondyli and may belong to a more exclusive clade therein.