(Bi-valv i-a)  (pely-cy-poda)
All of the Taxonomy is
UNDER CONSTRUCTION - Plus
Images are being added and the article is being updated Nov. 24, 2003

Latin;  bi=two   -  two plates (Two halves to the shell)     Pele=hatchet   pod=foot  hatchet foot (shape)

The Pelecypoda, Bivalva or Lamellibranchia (Latin for leaf-gill) (the only class with three names!!)  is comprised of molluscs known more commonly as just bivalves , because they have two separate halves to their shells.  They all have two-part shells, hinged dorsally.  The head is greatly reduced in size and their foot is laterally compressed. Their mantle cavity is the largest of all known molluscs.  Their gills tend to be very large and not only function for respiration, but aid in food-collecting as well.

Most bivalves have evolved to become burrowers. They have left the hard substratum of their ancestors and have learned to inhabit the massive mud, silt and sand bottoms of our oceans and freshwaters.  Some bivalves do however live on, or most often in hard substrata such as clay, rocks and wood.  These have become sessile (i.e., once adult, they don't move), or borers (example - the famous shipworms - of various families, including Litihophagidae (litho= wood, phag = eat: wood eater).

Teredo navalis (Linnaeus, 1758) Shipworms

NOTE: Shipworms are not a worm at all, but a greatly elongated clam . Its two shells, enclosing only the front end of the body, function as a tool, rather than a protective covering; their ridged and roughened surfaces are used for boring. They are actually a boring clam. Christened by mariners, "termites of the sea," shipworms are parasitic mollusks that thrive in and upon submerged wooden structures, including pilings, bulkheads and the untreated hulls of boats. They are quite destructive and have actually sunk many a wooden ship of old. As they tunne and eat the wood, their tunnel diameter actually increase in diameter due to their growth.

  Most bivalves are marine, and of these the majority live in the littoral, or intertidal zone. However, some species are found in the deepest abyssal zones of the oceans.  Some bivalve species and groups have adapted to living in brackish and freshwater environments. These are found in the freshwater families of the Unionidae (These will be discussed further down the page). Also, some of the "true" mussels (family Mytilidae) such as the infamous Zebra mussels are also found in brackish and fresh water.  Some of the bivalves lead a commensural life style:  living with other marine inhabitants, while still others have evolved to become parasites.

  During periods of low tide or drought, exposed fresh-water bivalves retain precious moisture by keeping totally inactive (which is called "aestivation": their metabolic rate drops to zero, so they can last a long time without water!), retaining fluid within their mantle cavity.

  Bivalves have long played a role in feeding the world's population. Another area where they are important is for man's ornamentation and adornment throughout the ages. Pearls are very economically important as a jewelry item, and many bivalve shells are used in various decorative ways. (See the Man and Mollusc article for details on the many interesting uses man has put molluscs, including bivalves to, over the centuries).

  Bivalves are highly specialized not only in their shape, but in their physiology as well.  Because of this specialization, most remain living in and on "soft bottoms" such as sand, silt and well-oxygenated mud.

   In summary, the taxonomy of the Pelecypods (bivalves, lamellibranches) is a twisted, complex affair, to be tackled at your own risk!

NOTE: Where possible in the following section, I will be showing a single representative species in each of the families listed. Occasionally, in cases of a shell being very rare and I am unable to provide an image but there is a web site to refer to , I will them list and link to that site. As with all links, that are not permanent in today's world of change. Should you find a broken link; I sure would appreciate it if you could notify me of this.
Thank you: Avril Bourquin

1. Subclass Protobranchia:  (Pro-to-branch-ia)  Latin: proto=front    branch=gill:  Primitive bivalves, their gills are not folded.  Palpal proboscides are frequently present.
	Order Nuculoida: Shell is aragonic with an interior that is nacerous or porcelaneous The periostracum is smooth. The valves are equal and have a row of sharp teeth along its hinge or border. Large palps used for food collection. Ctenidia are small and used only for gas exchange. Foot is longitudinally grooved and has a plantar sole. (Common Name: Nut Clams)
		Superfamilies, Families & Genus: Nuculanoidea Nuculanidae Ledellinae, Unplaced, Nuculaninae, Yoldiinae Malletiidae Malletia, Pseudomalletia, Bathymalletia Sareptidae Sarepta Neilonellidae Neilonella, Protonucula Nuculanoidea Nuculana elenensis (Sowerby, 1833) 12 mm Malletiidae Malletia cumingii (Hanley, 1860) 15 mm Sareptidae Unable to locate a shell or photo Neilonellidae Neilonella dubia Prashad, 1932 6 mm Nuculoidea Nuculidae Nuculinae Nucula, Acila, Pronucula, Nuculoma, Ennucula, Rumptunucula Tindariidae Tindariidae Tindaria, Spinula Nuculoidea Nucula semiornata (Orbigny, 1846) 5 mm up Tindariidae Tindaria striata (King & Broderip, 1831) 12 mm up
	Order Solemyoida: Shell valves are thin, equal in size, elongate and lacking hinge teeth. They have a large ctenidae used for both feeding and gas exchange. Their palps are small. (Common Name: awning clams)
		Superfamilies, Families & Genus: Solemyidae Solemya, Acharax Nucinellidae Nucinella, Huxleyia Solemyidae Solemya togata (Poli, 1795) 44 mm Nucinellidae Bulletin #35 Huxleyia cavernicola sp. nov. 0.9 mm

2. Subclass: Pteriomorphia: They possess attenuated, flexed gill filaments.  The filaments are incompletely fused; intercellular junctions are present but the adjacent filaments are joined only by ciliary tufts. They are primitive bivalves. (WAS: Superorder: Filibranchia:  (Phil-I-branch-ia): (also known as Pteriomorphia): Latin:  fil=thread    branc=gill
	Order Mytiloida: Shell valves are quite thin, elongated and equal in size.. The valves are uncalcified along the outer edges and hinge teeth are absent. They have one large ctenidia which is used both for feeding and gas exchange. Their palps are small.
		Families & Genus: Mytilidae: these are the sea mussels Mytilus, Brachidontes, Mytilaster, Perna, Crenella, Gregariella, Modiolarca, Musculus, Rhomboidella, Lithophaga, Myoforceps, Modiolus, Amygdalum, Dacrydium, Idas, Modiolula, Musculista, Xenostrobus, Bathymodiolus Mytilus californianus (Conrad, 1837) 100 mm. Perna viridus (Linnaeus, 1758) 50 mm.
	Order Arcoida:
		Superfamilies, Families & Genus: Arcoidea Noetiidae Noetinae Sheldonella, Noetiella, Estellacar, Verilarca, Spinearca, Didimacar, Striarcinae Striarcinae Striarca , Arcopsis Arcidae (mainly found in sand or mud in shallow and deep water, attached to a rocky or coralline substrate by means of a byssus.) inquirenda, Arca, Trisidos, Scaphula, Barbatia, Anadara, Bathyarca, Bentharca, Porterius, Samacar, Hawaiarca, Mosambicarca Cucullaeidae Cucullaea Noetinae Noetia reversa (Sowerby, 1832) 33 mm. Arcidae Arca navicularis (Bruguière, 1789) 27 mm. Cucullaeidae Cucullaea labiata (Lightfoot, 1786) 75 mm. Limopsoidea Philobryidae Philobrya, Hochstetteria, Neocardia, Adacnarca, Cratis, Notomytilus, Cosa, Micromytilus Limopsidae Limopsis, Lissarca, Empleconia, Nipponolimopsis,Crenulilimopsis Glycymerididae Incertae sedis, Glycymeris, Melaxinaea, Tucetona Philobryidae Cratis kanekoi (Hayami & Kase, 1993) Bulletin #35 1.5 mm Limopsidae Limopsis sulcata (Verrill & Bush, 1898) 14 mm Glycymerididae Glycymeris glycymeris (Linnaeus, 1758) 55 mm
	Order Pterioida
		Superfamilies, Families & Genus: Pterioidea Pulvinitidae Pulvinites Malleidae Vulsella, Malleus, Neoaviculovulsa Pteriidae Pteria, Pinctada, Electroma Isognomonidae Isognomon, Crenatula Pulvinitidae Unable to locate a shell or photo Malleidae Vulsella vulsella (Linnaeus, 1758) 50 mm. Pteriidae Pinctada margaritifera (Linnaeus, 1758) 200 - 250 mm. Isognomonidae Isognomon radiatus (Anton, 1839) 50 mm. Pinnoide Pinnidae Pinna, Atrina, Streptopinna Pinnidae Pinna nobilis (Linnaeus, 1758) 60 cm.
	Order Limoida
		Superfamilies & Family: Limoidea Limidae Lima, Limaria, Limea, Limatula, Ctenoides, Acesta, Limatulella, Divarilima, Fukama Limoidae Lima lima (Linnaeus, 1758) 40 mm.
	Order Ostreoida
		Superfamilies, Families & Genus: Pectinina Pectinoidea Spondylidae Spondylus Pectinidae Pecten, Pedum, Amusium, Chlamys, Decatopecten, Argopecten, Flexopecten , Lissopecten, Hyalopecten, Nodipecten, Patinopecten, Semipallium, Mimachlamys, Equichlamys, Mesopeplum, Veprichlamys, Notochlamys, Delectopecten, Cryptopecten, Anguipecten, Haumea, Mirapecten, Volachlamys, Juxtamusium, Annachlamys, Gloripallium, Excellichlamys, Bractechlamys, Minnivola, Coralichlamys, Serratovola, Somalipecten, Pseudohinnites, Glorichlamys Entoliidae Pectinella Propeamussiidae Propeamussium, Parvamussium, Cyclopecten, Cyclochlamys, Similipecten Spondylidae Spondylus americanus (Hermann, 1781) Photograph by Jim Miller 10 cm. Pectinidae Chlamys senatoria nobilis (Reeve, 1852) 7.5 cm. Entoliidae   Unable to locate a shell or photo     Propeamussiidae Cyclopecten zacae (Hertlein, 1935) (Rare-deep water) 14 mm. Anomioidea Anomiidae Anomiinae Anomia, Enigmonia Placunanomiinae Pododesmus, Patro, Monia Placunidae Placuna Anomiidae Anomia ephippium (Linnaeus, 1758) 65 mm. Placuniidae Placuna sella (Gmelin, 1791) 19 cm. Ostreina Ostreoidea Ostreidae Ostreinae Ostrea, Pretostrea, Planostrea, Booneostrea, Pustulostrea, Nanostrea Lophinae Lopha , Dendostrea, Alectryonella, Anomiostrea Crassostreinae Crassostrea, Saccostrea, Striostrea Gryphaeidae Pycnodonte, Hyotissa, Neopycnodonte, Parahyotissa Ostreidae Lopha cristagalli (Linnaeus, 1758) 9 cm. Gryphaeidae Hyotissa imbricata (Lamarck, 1819) 7.5 cm. Plicatuloidea Plicatulidae Plicatula Plicatuloidae Plicatula gibbosa ( Lamarck, 1801) 11 mm. (Jaxshells) Dimyoidea (freshwater mussels) Dimyidae Dimya Dimyoidea Etheria elliptica Lamarck, 1807

3. Subclass: Palaeoheterodonta (WAS: Order: Paleoheterodonta: There are about 1,200 species and it includes the nearly extinct family Trigoniidae (fewer than 6 living species) and the Unionoidea (fresh water bivalves)
	Order Trigonioida
		Superfamily, & Genus: Trigonioidea Trigoniidae Neotrigonia Trigonioidea Neotrigonia bednalli (Verco, 1907) 5 cm.
	Order Unionoida
		Superfamilies, Families: Unionoidea Hyriidae Incertae sedis, Hyridella, Alathyria, Cucumerunio, Lortiella, Velesunio, Westralunio Hyriidae2 Hyridella2, Lortiella2, Velesunio2, Alathyria2, Westralunio2, Cucumerunio2 Unionidae Unioninae Oguranodonta Hyriidae Velesunio ambiguus (Philippi, 1847) 57 mm. Hyriidae 2 Hyridella drapeta (Iredale, 1934) 54 mm. Unionidae Oguranodonta ogurae (Kuroda & Habe, 1987) 50 mm Muteloidea Muteloidae Iridina, Mutela Muteloidae Iridina spekei (Woorward, 1880) 99 mm.

4. Order Heterodonta ('het-er-o-'dän -ta) (Was Eulamellibranchia  (Eu-la-melli-branch-ia)    Latin:  eu=well, very    lamella=leaf, layer     branch=gill (also called the Paleoheterodonta and the Heterodonta - two subclasses often just lumped together as the Eulamellibranchs (and no, I don't know why nearly every taxonomic group in the bivalves has at least two names!!)   The reflexed gill filaments are morphologically fused to form true lamellae. )
	Order Veneroida: Usually thick-valved, equal valved and isomyarian.
		Superfamilies, Families & Genus: Chamoidea Chamidae Incertae, Chama, Pseudochama, Eopseuma, Carditochama Chamidae Chama lazarus (Linnaeus, 1758) 56 mm. Lucinoidea Lucinidae (A large, well-known family of usually white, hard-shelled clams in which the cardinal teeth are small, and the anterior muscle scar is narrow and long. There are no long siphons, so the clams make a tube to the surface with their foot. Many genera and species, worldwide, shallow to deep water. [from A&D, p.320]) Codakia, Loripes, Lucina, Anodontia, Myrtea, Ctena, Divaricella, Megaxinus, Austriella, Loripinus, Cavilucina, Phlyctiderma, Callucina, Bourdotia, Cardiolucina, Lucinoma, Pillucina, Notomyrtea, Epicodakia, Nevenulora, Wallucina, Monitilora, Divalucina, Saltocuna, Barbierella, Divalinga, Mesolinga, Rasta, Lamellolucina Ungulinidae Diplodonta, Cycladicama, Ungulina, Microstagon, Fellaniella, Numella Thyasiridae Thyasira, Leptaxinus, Tauraxinus, Parathyasira, Mayorithyas, Axinopsida Mactromyidae Bathycorbis Fimbriidae Fimbria Lucinidae Loripes lucinalis (Lamarck, 1818) 15 mm. Ungulinidae Felaniella vilardeboana (Orbigny, 1846) 17 mm. Thyasiridae Thyasira trisinuata Orbigny, 1842 9.5 mm Mactromyidae Unable to locate a shell or photo Fimbriidae Fimbria fimbriata (Linnaeus, 1758) 6.2 mm Galeommatoidea Galeommatidae: (a group with often internalized shells and active crawling behavior) Leiochasmea, Entovalva, Kellia, Lepton, Montacuta, Galeomma, Lasaea, Tellimya, Myllita, Scintilla, Mysella, Pseudopythina, Lionelita, Scintillula, Ephippodonta, Issina, Amphilepida, Pseudokellia, Levanderia , Borniola, Melliteryx, Scintillona, Arthritica, Barrimysia, Fastimysia, Virmysella, Divariscintilla, Ambuscintilla, Marikellia, Achasmea, Hitia , Radobornia, Kaneoha, Cicatellia, Parvikellia,Vermitexta, Fronsella, Pileatona, Paraborniola, Curvemysella, Montacutona Galeommatidae Myllita deshayesi (Orbigny & Récluz, 1850) 9.0 mm. Cyamioidea Cyamiidae Gaimardia, Cyamiomactra, Legrandina, Eugaimardia Neoleptonidae Neolepton, Puyseguria Sportellidae Sportella, Anisodonta, Basterotia, Isoconcha, Tahunanuia Cyamiidae Gaimardia trapezina (Lamarck, 1819) 16 mm. Neoleptonidae Neolepton species unknown 2.9 mm. (Jaxshells) Sportellidae   Unable to locate a shell or photo   Carditoidea Carditidae Incertae sedis Cardites tankervillii, Chama australis, Cardita jukesi, Cardita (Venericardia) pelseneeri Cardita, Beguina, Venericardia, Cardites, Glans, Arcinella, Cardiocardita, Thecalia, Cyclocardia, Carditella, Megacardita, Choniocardia, Hamacuna, Carditellopsis Condylocardiidae Condylocardiinae Micromeris, Condylocardia, Benthocardiella, Condylocuna, Cunanax, Austrocardiella, Isodontocardia Cuninae Cuna, Propecuna, Ovacuna, Warrana, Crassacuna, Mimicuna, Westaustrocuna Carditidae Cardites bicolor (Lamarck, 1819) 40 mm. Condylocardiidae Cuna gambiensis ( Nickles, 1955) 25 mm. Crassatelloidea Crassatellidae Incertae sedis Crassatella striata, Crassatella subradiata, Crassatella erycinea, Crassatella corbuloides, Crassatella jubar, Crassatella lapidea, Crassatella ornata, Crassatella triquetra, Crassatella ziczac, Crassatella compta, Crassatella concinna, Crassatella obscura, Crassatella truncata, Crassatella crebrilirata, Crassatella subquadrata, Crassatella indica Eucrassatella, Talabrica, Salaputium, Bathytormus Crassatellidae Crassatella brasiliensis (Dall, 1903) (A rare deep water species) 23 mm. Cardioidea Cardiidae Incertae sedis Cardium laevigatum, Cardium rigidum, Cardium (Trachycardium) arenicola, Cardium hiulcum, Cardium fornasinianum, Cardium istmicus, Cardium septuagenarium, Vepricardium monilectum, Cardium (?Fragum) centumliratum, Cardium (Ctenocardium) translatum, Clinocardium californiense bulowi, Cardium (Cerastoderma) iranjanense, Laevicardium (Vepricardium) rudentis Protocardiinae Nemocardium, Lyrocardium, Frigidocardium Cardiinae Incertae sedis, Acanthocardia, Bucardium, Parvicardium, Plagiocardium, Papillicardium, Rudicardia, Vepricardium Trachycardiinae Trachycardium, Acrosterigma, Vasticardium Fraginae Fragum, Corculum, Lunulicardia, Ctenocardia, Afrocardium, Microfragum Laevicardiinae Cerastoderma, Laevicardium, Fulvia, Keenocardium Hemidonacidae Hemidonax Cardiidae Corculum laevigatum (Lightfoot, 1786) 36 mm. Hemidonacidae   Unable to locate a shell or photo Tridacnoidea Tridacnidae (Giant clams (Cardiidae: Tridacninae) are among the most familiar marine invertebrates. Less well known is the remarkable fact that they are highly derived cardiids (cockles) whose adult morphology has been profoundly restructured by their long evolutionary association with photosymbionts. They have been severly over-harvested throughout much of their collective range and illegal fishing (poaching) remains a serious problem. ) Tridacna, Hippopus Tridacnidae Tridacna (Tridacna) gigas ( Linnaeus, 1758 ) up to 1.5 meters in length 333kg in weight Mactroidea Cardiliidae Cardilia Mactridae: Surf clams like to burrow in rocks, and the shell is consequently very strongly constructed. Incertae sedis Mactra cornea, Mactra opposita, Mactra sulcataria, Mactra symmetrica, Mactra incerta, Mactra, Mactra, Mactra taprobanensis, Mactra thaanumi Mactrinae Mactra, Spisula, Mactrinula, Diaphoromactra Lutrariinae Lutraria, Heterocardia, Meropesta Zenatiinae Zenatina Pteropsellinae Raeta Mesodesmatidae Incertae sedis Caecella transversalis, Paphia macrodon, Mesodesma intermedia Mesodesmatinae Paphies, Coecella Davilinae Davila, Anapella Cardiliidae Unable to locate a shell or photo Mactridae Mactrellona exoleta (Gray 1837) Mesodesmatidae Mesodesma donacium (Lamarck, 1818) 9 cms. Solenoidea Pharidae Siliqua, Cultellus, Phaxas, Ensiculus Solenidae Solen, Neosolen Pharellidae Pharella Pharidae Cultellus attenuatus (Dunker, 1862) 9 cm. Solenidae Solen viridis (Say, 1822) (See: jaxshells.org) 5 cm. Pharellidae Pharella javanica Lamarck, 1818) Tellinoidea Tellinidae (Tellin Clams) Tellininae Tellina, Peronaea, Angulus, Phylloda, Tellinides, Tellinella, Tellidora, Homalina, Eurytellina, Pharaonella, Serratina, Abranda, Macomona, Obtellina, Clathrotellina, Hemimetis, Arcopella, Laciolina, Florimetis Macominae Gastrana, Macoma, Macalia, Psammotreta, Apolymetis, Leporimetis Strigillinae Strigilla, Aeretica Arcopagiinae Arcopagia, Fabulina, Pseudarcopagia, Quadrans, Cyclotellina, Moerella, Merisca, Arcopaginula, Scutarcopagia, Exotica, Semelangulus, Pinguitellina, Quidnipagus, Jactellina, Punipagia, Pistris, Cadella, Loxoglypta Psammobiidae (Sunset Clams) Asaphis, Hiatula, Sanguinolaria, Gari, Psammacola, Soletellina, Heteroglypta, Psammotellina, Psammosphaerica Donacidae (Donax Clams) Donax, Hecuba, Heterodonax Solecurtidae (Solecurtus Clams) Solecurtus, Azorinus, Sinonovacula Semelidae Semele, Abra, Ervilia, Cumingia, Theora, Iacra, Leptomya, Lonoa, Abrina, Thyellisca, Leptomyaria Tellinidae Tellina rostrata (Linnaeus, 1758) 7.5 cm. Psammobiidae Asaphis deflorata (Linnaeus, 1758) 7 cm. Donacidae Donax trunculus (Linnaeus, 1758) 3 cm. Solecurtidae Solecurtus consimilis (Kuroda & Habe,1961) 6 cm. Semelidae Semele laevis (Sowerby, 1833) 2.1 cm. Arcticoidea Vesicomyidae Vesicomya, Callogonia, Calyptogena Kelliellidae Alveinus, Kelliella Trapeziidae Trapezium, Coralliophaga, Fluviolanatus Vesicomyidae Calyptogena magnifica (Boss & Turner, 1980) (This is a Deep Sea Vent Clam) [Collection of Emilio Jorge Power] Kelliellidae Alveinus ojianus (Yokoyama, 1927) (shell is only 0.5mm.) Trapeziidae Coralliophaga hyalina sp. nov. (Bulletin #35) Glossoidea Glossidae Glossus Glossidae Glossus humanus (Linnaeus, 1758) 9 cm. Corbiculoidea (freshwater) Corbiculidae Incertae sedis Cyrena eximia, Batissa triquetra, Cyrena affinis, Cyrena fallax, Cyrena oviformis, Cyrena ventricosa, Batissa australis, Cyrena essingtonensis, Cyrena impressa, Cyrena jukesi, Cyrena placida, Cyrenella moretonensis, Cyrenella sphaericula, Corbicula minor, Corbicula prolongata, Cyrena cyprinaeformis, Corbicula baronialis, Cyrena rugulosa, Cyrena solida, Corbicula deshayesii, Corbicula desolata, Corbicula faba, Corbiculina aramita, Corbiculina esculenta, Corbiculina finkeana, Corbiculina musson, Corbiculina semara Polymesoda, Batissa, Cyrenobatissa Corbiculidae Corbicula fluminea (Müller, 1774) Veneroidea Petricolidae Petricola, Mysia, Asaphinoides Veneridae (Venus Clams)"The family Veneridae has over 400 living species. It is one of the most colorful of the bivalve groups. Shape varies from circular to triangular, and from side view will appear as either ovate (egg-shaped) or cardioid (heart shaped) shells. Characterististics are: porcelain-like shell that is highly finished; a complex tooth structure in the hinge; a well developed escutchion and lunule; and, a well developed sinus at the pallial line. Spiny forms are comparatively uncommon in this family..." Incertae sedis Venerupis flabagella, Pitar (Pitar) varians, Venus maculata, Venus punctata, Cytherea concentrica var., Cytherea rufa, Venus truncata, Venus variflamma, Venus tessellata, Circe planata, Venus bella, Artemis turgida, Tapes geographica, Chione mitis, Venus fluctifraga, Saxidomus maximus, Venus consobrina, Venerupis chinensis, Venerupis digonea, Chione gibbosula, Chione sphaericula, Chione ustulata, Tapes similis, Dione crocea, Dione rufescens, Meretrix grata, Venus deshayesiana, Circe robillardi, Dosinia conglobata, Dosinia minor, Circe undata, Cytherea ambigua, Gouldia petterdi, Sunetta clessini, Circe gordoni, Callocardia (?) pacifica, Circe amica, Dosinia parva, Callista (Callocardia), Dorisca cookei Unplaced Kyrina, Privigna Venerinae Venus, Antigona, Periglypta, Globivenus Dosiniinae Dosinia, Phacosoma