5.9" Hoploscaphites Ammonite In Concretion - South Dakota

Hoploscaphites Ammonite In Concretion - South Dakota #98727

This is a gorgeous 5.9" Hoploscaphites (Jeletzkytes) ammonite specimen from the Fox Hills Formation of South Dakota. It's been nicely prepared from the hard concretion in which it was found and the base is flat enough that it will display nicely without the use of a stand.

About Ammonites

Ammonites were ancient marine cephalopods, similar to today's squids and octopuses, but with a defining feature: their distinctive, tightly coiled spiral shells. These shells, resembling those of modern nautiluses, served as both a protective home and a buoyancy aid, allowing ammonites to navigate the prehistoric seas with ease. First emerging around 240 million years ago in the Triassic Period, ammonites thrived for over 175 million years, adapting through numerous forms and sizes. As predatory creatures, they likely fed on smaller marine organisms, using their tentacles to capture prey. However, their long reign came to an end 65 million years ago at the close of the Cretaceous, coinciding with the mass extinction event that also eliminated the dinosaurs.

What an ammonite would have looked like while alive.