Pholadidae

Pholadidae, known as piddocks or angelwings, are a family of bivalve molluscs similar to a clam.

Background Piddocks are unique in that each side of their shells is divided into 2 or 3 separate sections. Furthermore, one of the piddock's shells has a set of ridges or "teeth", which they use to grind away at clay or soft rock and create tubular burrows. The shape of these burrows is due to the rotating motion of the piddock as it grinds the rock to make its home. The piddock stays in the burrow it digs for the entirety of its eight-year lifespan, with only its siphon exposed to take in water that it filters for food. When the piddock dies and leaves an empty tubular burrow, other marine life such as sea anemone, crabs and other molluscs may use the burrow.

Some species of Pholadidae may reach up to 18 cm (7″). Their coloration is typically white, though through consumption of red tide algae some may develop a pink coloration.

The Atlantic mud-piddock, Barnea truncata, often referred to as the fallen angelwing, is classed among the angelwing varieties, growing up to 5.7 cm (2¼″) and is similar to other angelwings but with weaker sculpture. One end is squared off and the other end pointed. Loose accessory plates are located above the hinge on live specimens. It possesses a white exterior and interior. It burrows into mud, clay or softwood. Occasionally it is washed onto sounds and ocean beaches, and has a habitat range from Nova Scotiahttp://www.registrelep.gc.ca/virtual_sara/files/cosewic/sr_Atlantic%20Mud-piddock_0810_e.pdf to Brazil. This fragile shell is rarely dug from mud without breaking. It burrows deeply and has long, united siphons. The false angelwing Petricola pholadiformis, is also classed among varieties of angelwing, growing up to 7 cm (2¾″). It has a thin, elongate shell resembling a small angelwing but lacks the rolled-out hinge area. Its beak is at one end of the shell with strong radial ribbing on the beak end. Teeth are located on hinge and a deep pallial sinus and partially united siphons. It has a white exterior and interior. It typically burrows into hard surfaces such as clay or peat in intertidal zones. It is commonly found on sounds and ocean beaches with a range from Canada to Uruguay. The common piddock (Pholas dactylus) is known for its bioluminescenceBasic information for Pholas dactylus (Common piddock)Vincent Pieribone and David F. Gruber. Aglow in the Dark: The Revolutionary Science of Biofluorescence. Harvard University Press, 2005. and was investigated by Raphaël Dubois in his 1887 discovery of luciferin.

Genera and selected species Genus Aspidopholas P. Fischer, 1887 Aspidopholas yoshimurai Kuroda & Teramachi, 1930 Genus Barnea Risso, 1826 Barnea candida (Linnaeus, 1758) Barnea davidi (Deshayes, 1874) Barnea fragilis (G. B. Sowerby II, 1849) Barnea manilensis (Philippi, 1847) Barnea parva Pennant, 1777 Barnea similis (Gray, 1835) Barnea subtruncata (G. B. Sowerby I, 1834) Barnea truncata (Say, 1822)

Genus Chaceia Turner, 1855 Chaceia ovoidea (Gould, 1851) Genus Cyrtopleura Tryon, 1862 Cyrtopleura costata (Linnaeus, 1758) Genus Diplothyra Tryon, 1862 Diplothyra smithii Tryon, 1862 Genus Jouannetia Desmoulins, 1828 Jouannetia quillingi Turner, 1955 Genus Lignopholas R. D. Turner, 1955 Lignopholas rivicola (G. B. Sowerby II, 1849) Genus Martesia G. B. Sowerby I, 1824 Martesia cuneiformis (Say, 1822) Martesia fragilis A. E. Verrill and Bush, 1890 Martesia striata (Linnaeus, 1758) Genus Netastoma Carpenter, 1864 Netastoma darwinii (Sowerby, 1849) Netastoma japonicum (Yokoyama, 1920) Netastoma rostratum (Valenciennes, 1846) Genus Nipponopholas Okamoto & Habe, 1987 Nipponopholas satoi Okamoto & Habe, 1987 Genus Parapholas Conrad, 1848 Parapholas californica (Conrad, 1837) Genus Penitella Valenciennes, 1846 Penitella conradi Valenciennes, 1846 Penitella fitchi Turner, 1955 Penitella gabbii (Tryon, 1863) Penitella hopkinsi Kennedy and Armentrout, 1989 Penitella kamakurensis (Yokoyama, 1922) Penitella penita (Conrad, 1837) Penitella richardsoni Kennedy, 1989 Penitella turnerae Evans and Fisher, 1966 Genus Pholadidea Turton, 1819 Pholadidea acherontea Beu and Climo, 1974 Pholadidea loscombiana Turton, 1819 Pholadidea spathulata (Sowerby, 1850) Pholadidea tridens (Gray, 1843) Genus Pholas Linnaeus, 1758 Pholas campechiensis Gmelin, 1791 Pholas dactylus Linnaeus, 1758 – common piddock Pholas orientalis Gmelin, 1791 Genus Talona Gray, 1842 Talona explanata (Spengler, 1792) Genus Zirfaea Gray, 1842 Zirfaea crispata (Linnaeus, 1758) Zirfaea pilsbryi Lowe, 1931

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Pholadidae

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