Mollusca
Abalones & relatives
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There are 8 species of abalones on the North American coast (Figs. 1 - 2). They were once abundant but, owing to their large size, ease of collection from shallow waters, tastiness, and high market value, they have been largely overfished – some to alarmingly low levels. White and black abalone are endangered species, while pink and green are also at great risk. Commercial fishing for abalone Haliotis kamtschatkana in B.C. has been closed since 1990 and that for H. rufescens south of San Francisco, California since 1997. Currently the only legal fisheries on the west coast is a recreational skin-diving one in northern California for red abalone that is closely regulated. Poaching is common for most or all species. Distributions of the 8 species are shown on the map.  Several other related types of gastropods, including turban and top shells (Figs. 3 & 4) are included in this section on abalones.

NOTE the English word “abalone” is derived from Sp. “aulon” or “aulone”, but it is not known what they were called in Britain before this adoption. Another English word for abalone, originating in the Channel Islands, is “ormer”. It is derived from the Fr. “oreille-de-mer”, meaning “sea ear”, in reference to the shape of the shell. The genus Haliotis also means “sea ear” in Greek. Its first occurrence in English literature was not until 1752 (Sir J. Hill referring to it as “the great ear shell”), so possibly prior to the 18th Century “ormer” was the name used in most or all areas of Great Britain

NOTE gastropods may be the most familiar of all marine invertebrates, not just because of their variety and “collectability” of their shells, but because of the diversity of habitats in which they live. They inhabit extreme areas such as deep-sea trenches and hot deserts, and live in soil, on trees, and in lakes, streams, and oceans. Most are shelled (which largely explains their diversity of habitats), but others lack shells or have partial shells. For these reasons, plus the fact that the central “character” in the story is a winkle, gastropods are well represented in the ODYSSEY. Replication between the various groups, however, is minimal, and what is emphasised for each taxon are the features that make its members unique.  If the few species of Calliostoma shown here seem a lot, note the WoRMS (World Register of Marine Species) lists over 600 world species in the genus

Fig. 1.  Distribution of 8 abalone species along the west coast of North America
Courtesy NOAA, U.S. Government
Fig. 2.  The most up-to-date review of west-coast abalones has provided these fine photographs. There are 7 species and one subspecies on the west coast from Southern California to Alaska, and another four subspecies from Baja California. The subspecies from Baja Califonia are not included here.
Courtesy Geiger & Owen 2019 Zoosymposia 13: 053
Fig. 3. Species of Tegula found along the west coast of North America
Fig. 4.  Five species out of about 20 in total of Calliostoma found along the west coast of North America

NOTE  C. zizyphinum is no longer recognised as a valid species

Alf   2019   Zoosymposia 13: 070
Tuskes   2019  

Research Study 1

Fig. 2.  Calliostoma species (cont.)

The trochid snail genus Calliostoma is a most successful group of marine snails.  There are lierally hundreds of species spread through the world's oceans, with 15 species in southern California alone, many of which are also found throughout more northerly regions and also some in southerly coastal regions. Most or all species are primarily sublittoral, with only a handful also being intertidal. Two researchers in the San Diego area with research ties to the University of California, Davis, and several Californian and other North American Museums have produced a fine display of these 15 species, with up-to-date species name-designations (Figs. 1 - 3)

 

Fig. 1.  Species of Calliiostoma present on the west coast of North America  
Tuske & Tuske   2019   The Festivus 51m(1): 11

ANIMATION of the snail's odyssey © Thomas Carefoot 2026
map used by the snail in A SNAIL'S ODYSSEY

To navigate through the ODYSSEY:

  • Select a TOPIC from the menu at the top of the screen
  • OR: play the animation to the left
  • OR: follow the snail's ODYSSEY by CLICKING on any X-marked invertebrate on the map above

Phylum Mollusca (lit. “soft” or “shellfish” L.)

Class Gastropoda (lit. “stomach foot” G.), referring to the body structure of viscera lying overtop of the muscular foot

SubClass Orthogastropoda (lit. “straight gastropod” G.), referring not to the shape of the shell but to aspects of their  phylogeny

SuperOrder Vetigastropoda¹; included together here for convenience are abalones and top shells in the following Families:

Family Haliotidae (lit. “sea” G.), including abalones (Haliotis)

Family Trochidae² (lit. “wheel” G.), including top and turban shells such as Tegula, Chlorostoma, Promartynia, Lirularia, Pupillaria (these last two were formerly in genus Margarites)

Family Calliostomatidae³ (lit. “more beautiful” “mouth” G.), including four genera of which Calliostoma is of most interest in the Odyssey

Family Turbinidae4 (lit. "spinning top" L.), including top shells Megastraea undosa

NOTE¹ another SuperFamily of Vetigastropoda, the Fissurelloidea that includes keyhole limpets Diodora, is considered elsewhere in the MOLLUSCA >LIMPETS & RELATIVES

NOTE² some years ago the classification of west-coast trochids underwent major changes. Some species were placed in the genus Chlorostoma (auretincta, brunnea, ligulata, and montereyi), one into Promartynia (pulligo), and one into Tegula (funebralis). Most recently, new changes now place the following species into genus Tegula: aureotincta, brunnea, eiseni, funebralis, gallina, pulligo, regina. Because of all of this, references to these species in the ODYSSEY may sometimes include the old genus name in brackets (e.g., Chlorostoma (Tegula) funebralis) or "Chlorostoma" in brackets (e.g., Tegula (Chlorostoma) funebralis), or may just use the same older name as used by an author. These new changes have clarified and simplified the taxonomy of the trochids.

NOTE³ a recent review of the genus Calliostoma includes about 27 species on the west coast from Alaska to Baja California, some in quite deep water. Of these, four are of interest because they have featured in Research-Study articles in the Odyssey (a fifth additional species from Europe is also included). Photographs of these five can be found below.

NOTE4 as noted above the top shell Astraea gibberosa has for some time been reclassified as Megastraea undosa

Alf   2019   Zoosympodia 13: 070
Tuskes   2019   Zoosymposia 13: 083