{"id":70579,"date":"2024-09-24T10:53:50","date_gmt":"2024-09-24T07:53:50","guid":{"rendered":"https:\/\/azalas.de\/de\/?p=70579"},"modified":"2026-01-17T19:00:13","modified_gmt":"2026-01-17T17:00:13","slug":"meerohren-und-lochschnecken","status":"publish","type":"post","link":"https:\/\/azalas.de\/en\/abalone\/","title":{"rendered":"Gastropoda 2: Abalone and Fissurellidae"},"content":{"rendered":"

T<\/big>he abalones (superfamily Haliotoidea<\/em>) and the keyhole and slit limpets (superfamily Fissurelloidea<\/em>) belong to the superorder Vetigastropoda<\/em>, as do the Trochidae<\/a>, which I discuss on a separate page. Together with almost all other snails, they form the subclass Orthogastropoda<\/em>. The limpets<\/a> on the other hand belong to a different subclass, the Eugastropoda<\/em>; despite their similarity, the limpets and the keyhole and slit limpets are not related.<\/p>\n

S<\/big>imilar to the limpets, the shells of the abalones and the Fissurellidae<\/em> are not or hardly coiled, and sit on the ground like a small hat or an upside-down plate. All species feed by grazing on algae or sponges and usually live hidden in the algae; they are often nocturnal and hide under stones during the day.<\/p>\n

The Photo gallery of the marine snails<\/strong><\/a> gives an overview over the species.<\/p>\n

A note on identification:<\/strong> Some species usually can be identified easily and reliably. In many cases, however, several related species are difficult to distinguish. Also not all species are included in the field guides; even using the internet, it is difficult to find information on some species. Accordingly, some of the identifications may not be correct.<\/small><\/p>\n

And a word about the names:<\/strong> As with many marine animals, there is a great deal of confusion surrounding the names of snails: for almost all species, a large number of synonyms exist that are no longer valid today but are still used in older books. I use the names according to the World Register of Marine Species<\/a> (as of 2020), where you can also find the corresponding synonyms.<\/small><\/p>\n

Here you can jump directly to the species<\/strong> (return with the back arrow or by swiping back):
\nAbalones, Haliotis<\/em><\/a>  –  Keyhole limpets, Diodora<\/em><\/a>  –  Slit limpets, Emarginula<\/em><\/a><\/p>\n

1. Haliotidae<\/em>, Abalones<\/a><\/h3>\n

A<\/big>balone shells can often be found on the beaches of Naxos; with their flat, open, slightly coiled shape and the shiny mother-of-pearl on the inside, they are easy to recognise. Abalone are much like limpets<\/a>, but live only underwater. They are hardly ever seen alive, because during the day, they hide under stones and rocks. At night, they crawl around and graze on algae. They can be found from the surface down to a depth of several meters. Like limpets, abalones are edible, but to my knowledge they are not eaten on Naxos.<\/p>\n

T<\/big>he shell of the abalones has a characteristic shape with a small coiled point and a large, flat, open last whorl, which shows irregular radial ridges on the outside and a row of small holes in the edge near the outer rim. The upper side is brownish in colour and usually covered with sessile organisms such as bryozoans; the underside is shiny and pearly. The living animal has a very broad foot with which it can hold itself firmly to the substrate. Small tentacles sit along the edge of the shell and short sensory filaments stretch out from the holes.<\/p>\n

Haliotis tuberculata<\/em>, L.<\/h6>\n

common<\/p>\n

\"Haliotis
\nThe flat, open shell of the abalones has a particularly beautiful, iridescent interior. The species Haliotis tuberculata<\/em> shows thick radial ridges on the shell; the upper side is grey in colour. Size: 45 mm<\/small><\/p>\n

Haliotis mykonosensis<\/em>; Owen, Hanavan & Hall<\/h6>\n

(= Haliotis tuberculata tuberculata)<\/em><\/p>\n

common, but a bit rarer than the previous species<\/p>\n

H<\/big>aliotis mykonosensis<\/em> was recently (2001) described as a separate species, which occurs mainly in Greece, but also in the central Mediterranean Sea as far as Corsica. It can be recognised by the less sculptured shell: the radial ridges are missing and the ribbing is finer. Haliotis mykonosensis<\/em> is not a generally accepted species; I am including it here nevertheless, because (as far as I understand) it is quite easy to distinguish.<\/p>\n

\"Haliotis
\nHaliotis mykonosensis<\/em> can be distinguished from the previous species by its smoother shell, which is brown, reddish or yellowish in colour. Size: 33 mm<\/small><\/p>\n

2. Fissurellidae<\/em>, Keyhole and slit limpets<\/h3>\n

T<\/big>he Fissurellidae<\/em> resemble the limpets, although they are not closely related. They differ in that their shell has a hole at the tip or a slit at the front edge. The shell is not round, but slightly oval in shape. The Fissurellidae<\/em> are usually found at depths of several meters. So far we found only once a live specimen, but empty shells are quite common on sandy beaches.<\/p>\n

Italian keyhole limpet, Diodora italica<\/em>, Defrance<\/a><\/h6>\n

T<\/big>he Italian keyhole limpet is quite common on Naxos. The shell of this species, which can grow to a length of 5 cm, is slightly “curved downwards” when seen from the side. The hole is located not exactly in the middle, but towards the narrower end of the oval shell. The colour is grey or greenish, often with darker radial stripes.<\/p>\n

\"Italian<\/p>\n

\"Italian
\nHere you can see a live Italian keyhole limpet from above; the elongated hole is visible a bit to the right from the middle of the oval shell.<\/small><\/p>\n

\"Italian
\nFrom the side, you see that the body is much thicker than that of limpets.<\/small><\/p>\n

Diodora gibberula<\/em>, Lamarck<\/h6>\n

T<\/big>he species Diodora gibberula<\/em> is rarer than the Italian keyhole limpet. Its shell is less oval in shape and the hole is closer to the center; the shell has fine and regular ribs which are not very pronounced. Viewed from the side, the shells are slightly curved downwards. The colouring is brownish.<\/p>\n

\"Diodora<\/p>\n

Slit limpets, Emarginula sicula<\/em>, J.E. Gray<\/a><\/h6>\n

T<\/big>he slit limpets have no hole in the center of their shells, but rather a small slit at the front end. The tip of the shell is curved more or less strongly towards the rear end. The living animals hide under stones or in rock crevices and are hardly ever seen; however, empty shells can occasionally be found on sandy beaches. Emarginula sicula<\/em> has a tall shell, up to about 1 cm in size, with a fine reticulate structure and a distinctly backward-curving tip.<\/p>\n

\"Emarginula<\/p>\n

Emarginula octaviana<\/em>, Coen<\/h6>\n

T<\/big>he shell of the species Emarginula octaviana<\/em>, which is very rare in our region, is lower than that of E. sicula<\/em>. The apex is shifted almost to the rear end. The reticulate sculpture is very distinct.<\/p>\n

\"Emarginula<\/p>\n

Emarginula huzardii<\/em>, Payraudeau<\/h6>\n

Emarginula huzardii<\/em> is particularly flat. The apex is very small and only slightly displaced towards the end; the reticulate sculpture is weakly developed.<\/p>\n

\"Emarginula
\nThe shells of this small species are very rare in our region, but this could also be due to the fact that they are quite thin and fragile.<\/small><\/p>\n

To the photo gallery<\/a><\/p>\n

continue: Trochidae<\/a><\/p>\n

see also: Limpets<\/a><\/p>\n

back:<\/p>\n