Home > Invertebrates > Sea Urchins

Updated 3/13/2016

Phylum Echinodermata, Class Echinoidea

Sea Urchins

Sea Urchins have radially symmetrical bodies divided into 5 equal parts.  They move about using articulating spines and tube feet.  Jawed tube feet called pedicellariae are employed for defense along with sometimes venomous spines.  Urchins feed upon algae, sponge, or detritus.  Their hard jaws and stout spines are capable of eroding coral or rock in some species.  Urchin roe is a delicacy in Japan and supports a fishery in the North Pacific.

For more information about sea urchins visit The Echinoid Directory.

 

Tube Feet

Mouth

 

HAWAII

Heterocentrotus mamillatus

Slate Pencil Urchin, Blowhole, 10 feet, 50mm

SLATE PENCIL URCHIN

 

Colobocentrotus atratus

SHINGLE or HELMET URCHIN

 

Echinometra mathaei

PALE ROCK-BORING URCHIN

 

Echinometra oblonga

BLACK ROCK-BORING URCHIN

 

Echinostrephus aciculatus

NEEDLE-SPINED URCHIN

 

Echinothrix diadema

BLUE-BLACK URCHIN

 

Diadema paucispinum

LONG-SPINED URCHIN

 

Diadema savignyi

SAVIGNY'S LONG-SPINED URCHIN

 

Echinothrix calamaris

BANDED URCHIN, banded morph

 

Echinothrix calamaris

BANDED URCHIN, black morph

 

Tripneustes gratilla

COLLECTOR URCHIN

 

Astropyga radiata

Blue-spotted Urchin, Maui, 20 feet, Photo by Kerry

BLUE-SPOTTED URCHIN

 

Nudechinus verruculatus

WARTY SAND URCHIN

 

Pseudoboletia indiana

PEBBLE-COLLECTOR URCHIN

 

Eucidaris metularia

TEN-LINED URCHIN

 

Chondrocidaris gigantea

ROUGH-SPINED URCHIN

 

Actinocidaris thomasi 

THOMAS' URCHIN

 

Prionocidaris hawaiiensis 

HAWAIIAN THORNY URCHIN

 

Leptodiadema purpureum

FINE-SPINED URCHIN

 

 

Acanthocidaris hastigera 

SPEAR URCHIN

 

 

Diadema sp. 1

UNIDENTIFIED LONG-SPINED URCHIN

 

Diadema sp. 2

UNIDENTIFIED THIN-SPINED URCHIN

 

Brissus latecarinatus

HEART URCHIN

 

Clypeaster reticulatus

RETICULATED SEA BISCUIT

 

Clypeaster sp.

GIANT SEA BISCUIT

 

Echinocyamus spp.

MINIATURE HEART URCHIN

 

Rhynobrissus hemiasteroides

HALF-STAR HEART URCHIN

   

INDO-PACIFIC

Toxopneustes pileolus

FLOWER URCHIN

 


JAPAN

Hemicentrotus pulcherrimus

GREEN SEA URCHIN    Bafun-uni

 

Strongylocentrotus intermedius

SEA URCHIN   Ezo Bafun-uni

Pseudocentrotus depressus

RED SEA URCHIN   Aka-uni

 

 

NORTHEAST PACIFIC

Strongylocentrotus droebachiensis

GREEN URCHIN

 

Strongylocentrotus purpuratus

PURPLE URCHIN

Mesocentrotus franciscanus

RED URCHIN

 

Centrostephanus coronatus

CROWNED URCHIN

 

Lytechinus pictus

WHITE URCHIN

 


TROPICAL WESTERN ATLANTIC

Meoma ventricosa

RED HEART URCHIN

 

Clypeaster rosaceus

INFLATED SEA BISCUIT

Diadema antillarum

LONG-SPINED URCHIN

 

Echinometra viridis

REEF URCHIN

 

Eucidaris tribuloides

 

SLATE-PENCIL URCHIN