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Updated 2/23/2026

Superfamily Rissooidea

Family Rissoidae, Rissoinidae, Zebinidae

These herbivorous micromollusks are associated with rocks and rubble.  Their small size makes identification a challenge.  Glassy shells become white when abraded.

 

HAWAII - ENDEMIC

Simularmerelina granulosa

GRANULOSE MERELINA

 

  
   

INDO-PACIFIC / HAWAII

Rissoina ambigua

 

AMBIGUOUS RISSO

 

 Apataxia cerithiiformis

 

OCHRE-BANDED RISSO
Rissoina costata

 

RIBBED RISSO

 Pandalosia ephamilla  

EPHAMILLA RISSO

 
Parashiela ambulata

BEETS' RISSO

 

 Schwartziella triticea  

TRIPLE RISSO
Sulcorissoina imbricata

STRIATED RISSO

 

 Zebina tridentata  

THREE-TOOTHED RISSO

 

  
   

Family Pickworthiidae

Pickworth shells

These tiny micromollusks were once lumped together within Family Rissoidae.  Their biology is unknown, with empty shells collected from sediment in deep caves.

 

HAWAII - ENDEMIC

Mareleptopoma kenneyi

KENNEY'S PICKWORTH

 

  
   

INDO-PACIFIC / HAWAII