Florent's Guide To The

Hawaii Reefs

Red Slate Pencil Urchin
Heterocentrotus mamillatus
Red Slate Pencil Urchin
Category: Sea Urchins
Scientific Name: Heterocentrotus mamillatus
Size: 5 to 10 in. (12 to 25 cm)  
Depth: 3-160 ft. (1-50 m)
Distribution: Indo-Pacific, Hawaii
Echinodermata (Phylum)
└Echinozoa (Subphylum)
 └Echinoidea (Class)
  └Euechinoidea (Subclass)
   └Camarodonta (Order)
    └Echinometridae (Family)
     └Heterocentrotus (Genus)
      └H. mamillatus (Species)

All Photographs
© 2026 Florent Charpin