- Description
- Despite a very similar shell, which permits them to strongly resist wave attack on exposed rocks, the keyhole limpets differ internally and externally from their cousins, the true limpets, or Patellacea. In both cases, a flattened foot acts like a strong suction disk, which adheres them to rock surfaces. Both move about in search of food, drawing in water around the foot, and they live either as scrapers of small detritus or as herbivores. In fissurellas, the volcano top is the exit port for waste products, rather than a mantle opening below the shell, as in the patellas. The internal organs of keyhole limpets are also modified to permit an exit channel through the body for waste products leaving at the top.
- Megathura crenulata, whose shell is shown (below right) is one of the largest known keyhole limpets. As can be seen in the linked site (below) a grayish mantle completely covers the shell in the live mollusc, leaving only the keyhole visible.
- Classification
- Class: Gastropoda
- Clade: Vetigastropoda
- Superfamily: Fissurelloidea
- Family: Fissurellidae
- Major Genera
- Genus: Clypidina
- Genus: Diodora
- Genus: Emarginella
- Genus: Fissurella
- Genus: Hemitoma
- Genus: Lucapinella
- Genus: Macroschisma
- Genus: Megathura
- Genus: Puncturella
- Genus: Rimula
- Genus: Tugali
- Genus: Zeidora
Diodora aspera (Rathke, 1833)
Rough Keyhole Limpet
Megathura crenulata (Sowerby, 1825)
Great Keyhole Limpet
SEE THE LIVING LIMPET:
(8th picture down):
| Megathura
crenulata Great Keyhole Limpet |
