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Canada's species



Snails | Clams and Mussels | Amphineura | Tusk Shells

Slug. Photo: Heather HaakstadThe Mollusca are an ancient group, arising over half a billion years ago and dominated the oceans before the coming of fish. They soon diversified and now include some of the best-known invertebrates: clams, snails, slugs, squids and octopi are all molluscs.

Their diversification has led to an extremely varied set of body plans and lifestyles, from completely armoured and virtually immobile filter-feeding clams to jetting carnivorous squids. Molluscs originally had shells, but many groups have now severely reduced or lost them, usually as they became more mobile. They are the largest, fastest, and smartest invertebrates.

One hundred and ten thousand species of molluscs exist today in seven classes: Cephalopoda (octopi, squids, nautilus and cuttlefish), Bivalvia (clams and mussels), Gastropoda (snails and slugs), Polyplacophora (chitons), Aplacophora, Monoplacophora, and Scaphopoda (tusk shells). Canada has 1 500 species, mostly gastropods and bivalves.


Snails (class Gastropoda)

Order Mesogastropoda

Brown Mystery Snail Campeloma decisum
Ribbed Valve Snail Valvata sincera sincera
Northern Valve Snail Valvata sincera helicoidea
Loosely-Coiled Valve Snail Valvata sincera ontariensis
Ordinary Spire Snail Amnicola limosa
Riverbank Looping Snail Pomatiopsis lapidaria
Great Lakes Horn-Snail Goniobasis livescens
Lacuna glacialis
Cingula castanea
Trichotropis borealis
Velutina undata

Order Basommatophora

Muskeg Stagnicola Stagnicola arctica
Eastern Physa Physa heterostropha
Umbilicate Promenetus Promenetus umbilicatellus
Oval Lake-Limpet Ferrissia fragilis

Order Archaeogastropoda

Puncturella noachina
Lepeta caeca
Margarites costalis

Order Neogastropoda

Volutopsius deformis
Admete couthouyi
Thesbia nana


Clams and Mussels (class Pelecypoda)

Order Eulamellibranchia

Western-River Pearl Mussel Margaritifera falcata
Pig-Toe Fusconaia flava
Western Floater Anodonta kennerlyi
Black Sand-Shell Ligumia recta
Eastern Elliptio Elliptio complanata
Olive Hickory-Nut Obovaria olivaria
Arctic-Alpine Fingernail Clam Sphaerium nitidum
Herrington's Fingernail Clam Sphaerium occidentale
Globular Pea Clam Pisidium ventricosum
Tiny Pea Clam Pisidium insigne


 Class Amphineura

Order Neoloricata

Tonicella marmorea
Lophyrochiton albus


Tusk Shells (class Scaphopoda)

Order Gadilida

Siphonodentalium lobatum