Limpets & relatives

About two dozen species of limpets live on the west coast of North America.   Keyhole limpets are not really closely related to limpets, but are included here for convenience.  There is also a small section on marine pulmonates, also not related to limpets, but resembling limpets in shape and behaviour. The photo series (Fig. 1) may be handy for identification of four common west-coast species.

NOTE  the word “limpet” originates from the Old English “lempedu”, itself derived from a similar Latin word, referring to the animal itself.  There have been several major revisions to west-coast limpet taxonomy over the past several decades.  At one time (e.g., Ricketts & Calvin 1939 - 1968 Between Pacific Tides Stanford Univ Press, Stanford), most species were classified in genus Acmaea (an exception being the owl limpet Lottia gigantea).  Several later revisions to the classification (e.g., Lindberg 1981 Acmaeidae Gastropoda MOLLUSCA The Boxwood Press, Pacific Grove, California; Lindberg 1986 Veliger 29: 142) treated west-coast biologists to a re-sorting of the species every few years into a number of genera including Acmaea, Lottia, Notoacmea, Tectura, Macclintockia, Discurria, and Collisella.  With the advent of modern molecular techniques, a latest and welcome re-classification has placed all west-coast Patellogastropoda (formerly known as Archaeogastropoda) in the genus Lottia, although the positioning is by no means certain.  The classification used here follows that of Lindberg 2007 p. 753 In, The Light and Smith Manual Intertidal invertebrates from central California to Oregon (Carlton, ed.) Univ Calif Press, Berkeley.  Simison & Lindberg (2003 Veliger 46: 1) have also clarified through molecular-sequencing data that Lottia strigatella and L. paradigitalis, long thought to be the same species are, in fact, separate species. The former is a southern California/Baja California resident, while the latter is distributed from the Aleutian Islands, Alaska to southern California.  Similarly, Lottia austrodigitalis has recently been separated as a sibling species, and Lottia insessa renamed as Discurria insessa.

There are a dozen or so university-sponsored marine research stations on this coast,  several of which offer undergraduate/graduate courses in marine study.  Most of these involve original research projects, often accompanied by “journal-ready” write-ups and symposium-style presentations to conclude the courses.  On at least two occasions, in 1964 and 1968 the focus at Hopkins Marine Station, California has been on research projects on specific organisms, namely, turban snails Tegula funebralis and limpets Lottia spp., respectively.  In each case, the course faculty/advisers arranged with the Editor of The Veliger journal to publish the student write-ups in specially dedicated Supplements to the regular journal numbers.  It is win-win for everyone. The students experience new challenges, gain valuable experience in formulating research hypotheses and implementing research protocols, get “published”, and have a lot of fun.  Does this influence their future career choice? Well, maybe.  A completely unscientific but probably fairly accurate survey using Google Scholar of how many of the students go on after graduating into scientific research, shows that of 20 who published papers on limpets in 1968, two carried on with marine-science research, three went into medicine/medical research/pharmacology, and the remainder moved into careers apparently not involving research publications.

Fig. 1.  Four visually troublesome limpets, nicely illustrated, top and bottom
Courtesy Linda Schroeder, Pacific Northwest Shell Club, Sea

ANIMATION of the snail's odyssey © Thomas Carefoot 2024
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/Clade Eogastropoda (lit. “early gastropod” G.)

SuperOrder/Clade Patellogastropoda (lit. “like a little dish” L. + gastropod), including limpets

Family Acmaeidae (lit. “point” or “highest point” G.), including dunce-cap limpets Acmaea mitra

Family Lottiidae, including all other limpets, Lottia spp.

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

SuperOrder/Clade Vetigastropoda

Family Fissurellidae (lit. “cleft” L.), including keyhole limpets Diodora aspera and giant keyhole limpets Megathura crenulata

SubClass/Clade Heterobranchia

Family Trimusculidae (lit. “three muscle” L.), including marine pulmonates Trimusculus reticulatus