Europasaurus' is a basal macronarian sauropod, a form of quadrupedal herbivorous dinosaur. It lived during the Late Jurassic (Kimmeridgian) of northern Germany, and has been identified as an example of insular dwarfism resulting from the isolation of a sauropod population on an island within the Lower Saxony basin. E. holgeri, named in 2006, is distinguishable from other sauropods such as Camarasaurus because of an evolutionary trend on small islands, where less resources than a large animal would need force the animal life to shrink, making Europasaurus the smallest macronian sauropod. Europosaurus was indeed small; its total length was only 6 metres or nearly 20 feet, & its shoulder height was level to an adult human's. Due to its smaller body, the neck looks disproportionately long.
Europasaurus was discovered in a bonebed as a herd. One suggestion has been that the herd was swept out to sea from a beach, drowning before becoming buried in the seabed. The only land near where the herd would have perished was a chain of small islands, the largest 200,000 km2, or 124,300 square miles. An area this small would have not been able to support Europasaurus' larger ancestors, forcing them to depreciate in size.
Europasaurus holgeri exhibits the following unambiguous autapomorphic states: "nasal process of premaxillary projecting anterodorsally; medial notch is posterior dorsal margin of cervical vertebral centra; scapular acromion with a prominent posterior projection; and transverse width of astragalus twice its dorsoventral height and anteroposterior width." In comparing Europasaurus with Camarasaurus, Europasaurus differs "in the wing-shaped posterior process of the postorbital being slightly longer and wider than the anterior process, whereas it is much shorter in Camarasaurus." Other differences include Europasaurus' shorter nasal-frontal contact and a parietal bone which is rectangular in posterior view.
Unlike Camarasaurus, the neural spines of the presacral vertebrae are undivided. In comparing Europasaurus with Brachiosaurus, the former genus differs from the latter by having a shorter muzzle, a quadratojugal which makes contact with the squamosal, and an anteromedially flattened humerus possessing unaligned proximal and distal epiphyses. Europasaurus was also compared with the macronarians Lusotitan and "Cetiosaurus" humerocristatus and found to be distinct from both those forms. Finally, Europasaurus can be distinguished from most known members of the Neosauropoda by its very small adult body size.