Lot: 5Kg Bumpy Ammonite (Douvilleiceras) Fossils - 24 pieces

This is a wholesale lot of 24 Douvilleiceras ammonites weighing 5kg from the Upper Cretaceous of Madagascar. They range in size from 2.5 - 3.5". This genus of ammonites has earned the local name "Tractor Ammonites", due to their distinctively bumpy surface and pronounced ridges making them resemble a tractor tire.

About Ammonites

Ammonites were predatory, marine mollusks that thrived during the Paleozoic and Mesozoic eras, particularly in the Jurassic and Cretaceous periods, before going extinct around 66 million years ago. These creatures are characterized by their coiled, spiral shells, which resemble the modern-day nautilus. Ammonite shells were divided into chambers; as they grew, they built new chambers and sealed off the old ones. These chambers were filled with gas, which helped them control buoyancy in the ocean.

The outer shell of ammonites often displays intricate ribbed or ridged patterns and their fossils sometimes show a wide range of beautiful colors due to mineralization over time. The shells fossilized well, making ammonites abundant in the fossil record.. In addition to being popular in fossil collections, ammonites are valuable in geological studies, as they serve as index fossils, helping scientists date rock layers and understand the Earth's prehistoric environments.

Artist's reconstruction of an ammonite,  by Nobu Tamura
Artist's reconstruction of an ammonite, by Nobu Tamura
SOLD
DETAILS
SPECIES
Douvilleiceras mammilatum
LOCATION
Mahajanga Province, Madagascar
SIZE
2.5 - 3.5"
ITEM
#103219
GUARANTEE
We guarantee the authenticity of all of our specimens.