Tuesday, 25 June 2019


Fossil Sand Dollars / Cassibuloid Ancestry
These lovelies are fossil sand dollars with their beautiful five-fold radial symmetry and petal-like pattern. They are echinoids, a group of lovely echinoderms with flattened, rigid, globular skeletons made of thin calcium carbonate plates. They look a bit like sea-biscuits and are sometimes referred to as such.

Their ancestors diverged from an irregular order of echinoids called cassibuloids during the Jurassic. The first true genus of sand dollar, Togocyamus, arose during the Paleocene. While millions of years old, they retain their recognizable form and look very similar to ones we might find living in our oceans and along burrowing on our beaches today.