Holotype specimen
Scientific classification
Kingdom: Animalia
Phylum: Chordata
clade: Neosauropoda
Order: Saurischia
Suborder: Sauropodomorpha
Family: Brachiosauridae?
Genus: Angloposiedon
Naish, 2010
Species: A. gigas
Binomial name
Angloposeidon gigas
in press

Angloposeidon is an extinct sauropod dinosaur from the Early Cretaceous of southern England. It was a possible brachiosaurid but has not been formally named. Darren Naish, a notable vertebrate palaeontologist, has worked with the specimen and has recommended that this name only be used informally and that it not be published. However, he published it himself in his book Tetrapod Zoology Book One from 2010. The remains consist of a single cervical vertebra (MIWG.7306), which indicate it was a very large animal. The fossil was found on the Isle of Wight in the Wessex Formation.