Prionocidaris verticillata Knobby Sea Urchin Sea Hedgehog Echinoderma Echinozoa Echinoidea Regularia Cidaridae

Prionocidaris verticillata Knobby Sea Urchin cm 2-3 Sea Hedgehog Echinoderma Echinozoa Echinoidea Regularia Cidaridae.
Dive collected in September 2020 at 20-30 meters deep.
Family: Cidaridae, Sottofamiglia Stylocidarinae.
Common name: Knobby Green Sea Urchin.
Syn. Plococidaris verticillata, Cidarites verticillata.

Plococidaris verticillata is a species of sea urchin in the family Cidaridae.
It is a regular and robust sea urchin, with a spherical and thick dermaskeleton, measuring about ten centimeters at most. The quills are lined up in five double vertical rows; they are sparse but very robust and have a very characteristic shape of turrets equipped with "stages" formed by successive crowns with irregular points. They bear three or four whorls of secondary spines more or less welded in concave corollas, separated by a straight but very grainy body.
This sea urchin has long been classified in the genus Prionocidaris and still is in many scientific publications. It should not be confused with other sea urchins with spiny spines of the genera Prionocidaris and Chondrocidaris, nor especially with the very similar Goniocidaris tubaria, found in Australia.
It is a tropical sea urchin that can occasionally be encountered in the coral reefs of the Indo-Pacific, from the coast of East Africa to the western Pacific. It is however quite rare.