Tanystrosuchus (meaning "long crocodile") is a dubious genus of theropod dinosaur from the late Triassic period (middle Norian stage, around 208 million years ago).

It is known from a single fossil neck vertebra of the species T. posthumus, found in the Middle Stubensandstein formation of what is present-day Germany.

In 1907, Friedrich von Huene examined the fossil and recognized it as part of a theropod dinosaur.

[2] The vertebra was added to the collections of the Staatliches Museum for Naturkunde in Stuttgart, but was labelled as a specimen of the phytosaurid Nicrosaurus.

In 2000, Oliver Rauhut and Axel Hungerbühler re-examined the specimen and concluded that, while it was similar in some respects to the same bone in the contemporary Liliensternus, and was definitely from a theropod, it could not be classified due to its incomplete nature.