Xenoposeidon falls under the superorder Dinosauria, suborder Sauropodomorpha, and belongs to the family Titanosauridae. Its precise position within the titanosaurs is uncertain due to the scarcity of fossils. Nevertheless, analysis of the limited material indicates that Xenoposeidon might represent an early or intermediate stage in the evolutionary tree of titanosaurs.

From the available fossil evidence, it is inferred that Xenoposeidon was a large herbivorous dinosaur, measuring approximately 15 to 20 meters (49 to 66 feet) in length. Its most notable characteristic lies in its long neck, estimated to be around 9 meters (30 feet) long, granting the dinosaur access to vegetation in elevated areas. Its body was supported by a robust skeletal structure, including sturdy limb bones and a powerful tail.

Due to the paucity of fossil remains, definitive conclusions about Xenoposeidon's biology and behavior remain elusive. Nevertheless, its distinctive anatomical features offer valuable insights into the evolutionary adaptations of titanosaurs. The elongated neck suggests a specialized feeding strategy, potentially enabling Xenoposeidon to exploit food sources not readily accessible to other sauropods.