Robust Jimbacrinus bostocki Crinoid Museum Fossil

Description: Jimbacrinus bostocki fossils have become increasingly difficult to obtain in the last few years. I was able to acquire two at the 2012 Tucson Mineral and Fossil Show. This specimen is fully 3D and nicely positioned on a red ocher colored plate. It was skillfully prepared to show exquisite detail of the arms and calyx. Note that ¾” of the stalk is attached.

Jimbacrinus had five arms that were lined with fine tentacle-like structures called pinnules. Like all crinoids, it used these unfurled arms to feed on small animals and particles in the water. Fossils of Jimbacrinus show that they were abundant seafloor animals in what is now Western Australia during the Permian. They grew to approximately nine inches in length.

The crinoids have a long history. They were the first echinoderms to appear in the fossil record, and have kept their early structure throughout their long career. They were extremely common in the Palaeozoic, and some rocks from the Carboniferous consist almost entirely of fossil crinoids..