Adaptations of the amazing Shingle Urchin

The Shingle urchin, Colobocentrotus atrata (Echinometridae), has a peculiar limpet-life morphology, unique among the regular echinoids. 

The aboral spines of Colobocentrotus atrata (on the opposite side to the mouth) are extremely reduced, forming a smooth pavement or plates, and the adoral part (situated near the mouth) is surrounded by a basal skirt of flattened spines. These two features improve the adhesive capacities of the animal and are adaptations to life in areas of extreme wave exposure throughout the Indo West Pacific where this sea urchin lives.


Photo credit: Shingle urchin in Pu’uhonua o Honaunau National Historical Park, Hawaii (the big island), Hawaii | ©Marlin Harms 

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Rock Boring Urchin (Echinometra lucunter)

…a species of Echinometrid sea urchin, which occurs in shallow areas in the western Atlantic Ocean and Caribbean Sea. Like other sea urchin species E. lucunter will feed on a range of marine plants and algae. True to its common name E. lucunter uses the teeth on its Aristotle’s lantern to grind away at rock allowing it to conceal itself. 


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Image: Hans Hillewaert

Pencil Urchin - Heterocentrotus sp.

A stunning close up of the surface of a Pencil Urchin, probably belonging to the genus Heterocentrotus (Echinometridae), whose spines are very thick and dense, with three or more flattened facets.

Photo credit: ©Mike Roberts | Locality: not indicated (2005)

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Reef Urchin (Echinometra viridis)

…a species of Echinometrid sea urchin which occurs on reefs in the Caribbean Sea from Florida to Venezuela. Reef urchins will conceal themselves in rock crevices during the day and will emerge at night to feed. Reef urchins are grazers and will feed on a variety of fleshy algae. 


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Image: Nhobgood

Slate Pencil Urchin - Heterocentrotus mamillatus

The characteristic spines of the sea urchin Heterocentrotus mamillatus (Echinoida - Echinometridae) really seem crayons, hence its common name.

Spines of sea urchins are appendages that are associated with defense, locomotion, and food gathering. Spines form an important part of an urchin’s maintenance mechanisms, and it is no surprise to find that they are repaired rapidly once damaged.

This species is found in tropical waters of Eastern Africa, Kenya, Madagascar, Marsa Shagra, Mascarene Basin, Mauritius, Red Sea, Seychelles and the West Indian Ocean.  

Other common names: Red slate pencil urchin, Red pencil urchin.

References: [1] - [2] - [3]

Photo credit: ©Russell Gilbert | Locality: Oahu, Hawaii (2014)

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