Fossils found in Spain belong to what was probably Europe's biggest ever dinosaur, according to scientists.
Turiasaurus would have been 30 to 37 metres long, and would have weighed between 40 and 48 tonnes.
Writing in the journal Science, researchers say the beast is probably the only member so far discovered of a European group of Jurassic reptiles.
The world's biggest recorded dinosaur is Argentinosaurus, a South American reptile twice as heavy.
Like the rest of the giant long-necked sauropods, Turiasaurus riodevensis was a herbivore, despite the fierce appearance of its teeth.
Fossils came to light in 2004 at Teruel in eastern Spain, and the scientists responsible, from the Fundacion Conjunto Paleontologico de Teruel-Dinopolis, have just published a formal analysis.
Although languishing some way behind Argentinosaurus, Turiasaurus was a substantial specimen.
Much of what we know of Turiasaurus is based on a study of its teeth
At 1.79m long, its humerus (upper arm bone) is one of the largest ever recorded, while one of its claws is comparable with a rugby ball or American football.
The discovery site also contains teeth from theropod dinosaurs, Stegosaurus remnants, and fragments from fish and turtles.
By comparing its features with other European dinosaurs, the scientists deduce that it belongs to a previously unknown clade, or grouping, which evolved in the Jurassic period (200 to 145 million years ago).
Teeth excavated in France, Portugal and the UK are similar, indicating that Turiasaurus, or more likely its close relatives, ranged across the continent.