| Patella ferruginea | |
|---|---|
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| Patella ferruginea fromMelilla | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Patellogastropoda |
| Family: | Patellidae |
| Genus: | Patella |
| Species: | P. ferruginea |
| Binomial name | |
| Patella ferruginea | |
| Synonyms[1] | |
List
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Patella ferruginea, commonly known as theferruginous limpet (sometimes, as theribbed Mediterranean limpet) is aspecies oftrue limpet, a marinegastropodmollusk in thefamilyPatellidae.[1] It is a large limpet, endemic to the westernMediterranean Sea, and although common in the past, it is now rare and restricted to only a few locations.
Patella ferruginea is a distinctive large limpet with a thick heavy shell. It can exceed 100 mm (4 in) in diameter, but usually barely exceeds 70 mm. The robust, cone-shaped shell has thirty to fifty broad ridges and a wavy margin. The ribs are irregular and sometimes nodular; the shell is often worn smooth or covered withepibiotic organisms such asalgae andbarnacles. The external surface is cream-coloured or rusty brown, while the inside is marbled white with a dark muscle scar. The muscular foot is yellowish-orange with dark grey sides, and thetentacles are black. Juveniles have flattened shells which are whitish with dark concentric bands and a small number of broad ribs, giving them star-shaped outlines.[2]
This limpet is restricted (endemic) to the Mediterranean Sea. In the past it had a wide range in the western Mediterranean, as evidenced by large shellmiddens formed byPaleolithic andNeolithic hunter gatherers.[2] It is now limited to a few locations in northwestern Africa, one of which is theAl Hoceima National Park,[3] as well as a few scattered locations in southern Spain, Gibraltar, Sardinia and Corsica, and some islets in the central Mediterranean. It lives on rocky surfaces in theintertidal zone. It is classified as an "endangered species" by Spain, and is the first invertebrate, as well as the first marine species, for which Spain has developed a national conservation strategy.[2]
This limpet is found in the mid-littoral zone, at the lower end of the zone occupied by the barnacleChthamalus stellatus and above that formed by red algae, where the gastropod molluscDendropoma petraeum is to be found. At night and when submerged, it travels to graze on the film ofcyanobacteria and young algae that forms on rocks, returning to the same homing site each time the tide recedes. This spot is discernible because a ring ofcoralline algae develops under the edge of the shell. The limpet facespredation from the crabsEriphia verrucosa andPachygrapsus marmoratus, and the dog winkleStramonita haemastoma.[2]
Breeding takes place in the autumn at about the time of year when the first storms occur, withgametes being liberated into the sea. Thelarvae areplanktonic for a while before settling in similar habitats to those occupied by the adults. This limpet appears to be aprotrandrous hermaphrodite, smaller individuals always being male and the proportion of females among larger individuals increasing with size. However, there is some indication that individuals can change sex in either direction.[2]
This limpet is on the verge of extinction in Spain, where fewer than a thousand individuals are thought to exist. More healthy populations are present in North Africa, with the largest being inMelilla,Ceuta and theChafarinas Islands, as well as theHabibas Islands off the coast of Algeria. Populations in Sardinia and Corsica seem to be declining.[2]
