Europasaurus

Europasaurus[1] is a basal macronarian sauropod, a form of quadrupedal herbivorous dinosaur. It lived during the Late Jurassic (middle Kimmeridgian, about 154 million years ago[1]) 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.

Description
Europasaurus holgeri exhibits the following unambiguous autapomorphic states:[1] "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,[1] 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,[1] 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.

Discovery
Remains of both adults and juveniles have been recovered from marine carbonate beds ("bed 93"), representing more than eleven individuals ranging from 1.7 to 6.2 meters in total body length. The genus name means "lizard from Europe" (Europe + Greek sauros = lizard), and the species is named in honor of Holger Lüdtke, who discovered the first fossils of the taxa. The holotype specimen (DFMMh/FV 291; Dinosaurier-Freilichtmuseum Münchehagen/Verein zur Förderung der Niedersächsischen Paläontologie) consists of portions of a disarticulated skull, along with cervical and sacral vertebrae, derived from a single individual. This specimen and all others referred to the taxon were collected from "bed 93" at the Langenberg quarry, Oker near Goslar, Lower Saxony (Niedersachsen). The species was named by Octávio Mateus, Thomas Laven, and Nils Knötschke in 2006.