Tropaeum

{{Short description|Genus of molluscs (fossil)}}

{{about||the ancient Greek or Roman victory monument|Tropaion|the city in Scythia Minor|Civitas Tropaensium}}

{{Automatic taxobox

| fossil_range = Early Cretaceous

| image = Tropaeum_imperator.JPG

| image_caption = Tropaeum imperator

| taxon = Tropaeum

| authority =Sowerby, 1837

| subdivision_ranks = Species

| subdivision =

• T. imperator
• T. undatum
• T. bowerbanki
• T. rasgradensis
• T. australis
• T. loegteri

}}

Tropaeum is an extinct genus of ammonites found throughout the oceans of the world during the Early Cretaceous. As with many other members of the family Ancyloceratidae, there was a trend among species within this genus to uncoil somewhat, in a very similar manner to the genus Lytoceras. The largest species, T. imperator of Australia, had a shell a little over one meter in diameter.

The name "Tropaeum" was applied by paleontologist James De Carle Sowerby, in 1837.