It lived during the Late Jurassic (middle Kimmeridgian, from about 154 to 151 million years ago) 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.

In 1998, a single sauropod tooth was discovered by private fossil collector Holger Lüdtke in an active quarry at Langenberg Mountain, between the communities of Oker, Harlingerode and Göttingerode in Germany.

The layers exposed in the quarry are oriented nearly vertically and slightly overturned, which is a result of the ascent of the adjacent Harz mountains during the Lower Cretaceous.

Access to the bone-bearing layer required the removal of some 600 tons of rock using excavators and wheel loaders, and the constant pumping out of water from the base of the quarry.

The campaign resulted in the discovery of new fish, turtle, and crocodile remains, as well as valuable information of the bone-bearing layer; additional Europasaurus bones, however, could not be located.

[1][2] Aside from being a very small neosauropod, Europasaurus was thought to have multiple unique morphological features to distinguish it from close relatives by its original describers, Sander et al. (2006[1]).

Comparisons with Brachiosaurus (now named Giraffatitan) were also mentioned, and it was identified that Europasaurus has a shorter snout, a contact between the quadratojugal and squamosal, and a humerus (upper forelimb bone) that has flattened and aligned proximal and distal surfaces.

There were finally quick comparisons to the potential brachiosaurid Lusotitan, which has a different ilium and astragalus shape, and Cetiosaurus humerocristatus (named Duriatitan), which has a deltopectoral crest that is less prominent and extends across less of the humerus.

Unlike the nasals of Giraffatitan, those in Europasaurus project horizontally forwards, forming a small portion of the skull roof over the antorbital fenestrae.

The frontals form a portion of the skull roof, articulating with other bones such as the nasals, parietals, prefrontals and postorbitals, and they are longer antero-posteriorly than they are wide, a unique character among a eusauropodan.

The frontals are also excluded from the supratemporal fenestra margin (a widespread character in sauropods more derived than Shunosaurus), and they only have a small, unornamented participation in the orbit.

the parietals are also wide when viewed from the back of the skull, being slightly taller than the foramen magnum (spinal cord opening).

There are two prominences projecting from the back of the jugal body, which diverge at 75º and form the bottom and front edges of the infratemporal fenestra.

Like in Riojasaurus and Massospondylus, two non-sauropod sauropodomorphs, the jugal forms a large part of the orbit edge, from the back to the front bottom corner.

[7] Front dorsal vertebrae are strongly opisthocoelous like the cervicals, and can be placed in the series based on the absence of the hypantrum and low parapophysis placement.

The internal structures are open and camerate like Camarasaurus, Giraffatitan and Galvesaurus, but unlike these taxa this pneumaticity does not extend into the middle and posterior dorsal vertebrae.

The middle dorsals possess a pneumatic cavity that extends upwards into the neural arch, like in Barapasaurus, Cetiosaurus, Tehuelchesaurus, and Camarasaurus.

All analyses resulted in similar phylogenetics, where Europasaurus placed more derived than Camarasaurus but outside a clade of Brachiosauridae and Titanosauromorpha (now named Titanosauriformes).

The results of the favoured analysis of Sander et al. (2006) are shown below on the left:[2] Omeisaurus Euhelopus Diplodocoidea Camarasaurus Europasaurus Brachiosaurus Cedarosaurus Lapparentosaurus Phuwiangosaurus Pleurocoelus Titanosauria Haplocanthosaurus Camarasaurus Bellusaurus Europasaurus Galvesaurus Tehuelchesaurus Tastavinsaurus Euhelopus Titanosauromorpha Brachiosaurus Giraffatitan Paluxysaurus Venenosaurus Cedarosaurus

Based on this newer and more expansive analysis, Europasaurus was found to be in a similar placement, as a basal camarasauromorph closer to titanosaurs than Camarasaurus.

While there was strong support in the phylogeny for its placement, Europasaurus, one of few basal macronarians with a skull, lacks multiple bones that display characteristic features of the group, such as caudal vertebrae.

[17] Camarasaurus Tehuelchesaurus Europasaurus Giraffatitan Brachiosaurus Abydosaurus Cedarosaurus Venenosaurus Ligabuesaurus Sauroposeidon Tastavinsaurus Euhelopodidae Chubutisaurus Titanosauria Camarasaurus Tehuelchesaurus Europasaurus Brachiosaurus Giraffatitan Lusotitan Sonorasaurus Abydosaurus Cedarosaurus Soriatitan Tastavinsaurus Venenosaurus Ligabuesaurus Sauroposeidon Euhelopodidae Chubutisaurus Titanosauria

This phylogeny, conducted by D'Emic et al. (2016), resolved a very similar placement of Europasaurus within Brachiosauridae, although Sonorasaurus was placed in a clade with Giraffatitan, and Lusotitan was placed in a polytomy with Abydosaurus and Cedarosaurus.

A larger specimen (DFMMh/FV 291.9) at 2 m (6.6 ft) shows large amounts of laminar tissue, with no growth marks present, so is likely a juvenile as well.

Unlike all other specimens, this one (DFMMh/FV 415) shows the presence of lines of arrested growth, indicating it died after reaching full body size.

[25] The dwarfism in Europasaurus represents the only significant rapid body mass change in derived Sauropodomorpha, with the general trend of taxa being a growth in overall size in other groups.

This does not indicate that the taxa present were marine, as the animals and plants may have been deposited allochthonously (albeit only by a short distance) from the surrounding islands.

There are large numbers of marine bivalve fossils, as well as echinoderms and microfossils present in the limestone of the quarry, although many of the animals and plants were terrestrial.

[27][30][31] Actinopterygian fish are abundant, being represented by Lepidotes, Macromesodon, Proscinetes, Coelodus, Macrosemius, Notagogus, Histionotus, Ionoscopus, Callopterus, Caturus, Sauropsis, Belonostomus, and Thrissops.

[27][38] Dinosaur footprints preserved at the Langenberg Quarry display a possible reason for the extinction of Europasaurus, and potentially other insular dwarfs present on the islands of the region.