View source for Pholadidae

{{Short description|Family of bivalves}}
{{Automatic taxobox
| fossil_range = {{fossil range|Jurassic|Recent}}
| image = Angelwing-shell.jpg
| image_caption = One valve of a shell of ''[[Cyrtopleura costata]]''
| taxon = Pholadidae
| authority = [[Jean-Baptiste Lamarck|Lamarck]], 1809
| display_parents = 2
| subdivision_ranks = Genera
| subdivision = See text
}}
'''Pholadidae''', known as '''piddocks''' or '''angelwings''', are a [[family (biology)|family]] of [[bivalve]] [[mollusc]]s 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 (mollusc)|siphon]] exposed to take in water that it [[Filter feeder|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&nbsp;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&nbsp;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 Scotia]]<ref>http://www.registrelep.gc.ca/virtual_sara/files/cosewic/sr_Atlantic%20Mud-piddock_0810_e.pdf {{Dead link|date=February 2022}}</ref> 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&nbsp;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 [[bioluminescence]]<ref>[https://www.marlin.ac.uk/species/detail/1403 Basic information for Pholas dactylus (Common piddock)<!-- Bot generated title -->]</ref><ref>Vincent Pieribone and David F. Gruber. ''Aglow in the Dark: The Revolutionary Science of Biofluorescence.'' Harvard University Press, 2005.</ref> and was investigated by [[Raphaël Dubois]] in his 1887 discovery of [[luciferin]].
==Genera and selected species==
* Genus ''[[Aspidopholas]]'' <small>P. Fischer, 1887</small>
** ''[[Aspidopholas yoshimurai]]'' <small>Kuroda & Teramachi, 1930</small>
* Genus ''[[Barnea (bivalve)|Barnea]]'' <small>[[Antoine Risso|Risso]], 1826</small>
** ''[[Barnea candida]]'' <small>[[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]</small>
** ''[[Barnea davidi]]'' <small>(Deshayes, 1874)</small>
** ''[[Barnea fragilis]]'' <small>(G. B. Sowerby II, 1849)</small>
** ''[[Barnea manilensis]]'' <small>([[Rodolfo Amando Philippi|Philippi]], 1847)</small>
** ''[[Barnea parva]]'' <small>Pennant, 1777</small>
** ''[[Barnea similis]]'' <small>(Gray, 1835)</small>
** ''[[Barnea subtruncata]]'' <small>(G. B. Sowerby I, 1834)</small>
** ''[[Barnea truncata]]'' <small>([[Thomas Say|Say]], 1822)</small>
[[Image:Barnea candida-Nl2.jpg|thumb|Two views of a whole shell of ''[[Barnea candida]]'']]
* Genus ''[[Chaceia]]'' <small>Turner, 1855</small>
** ''[[Chaceia ovoidea]]'' <small>(Gould, 1851)</small>
* Genus ''[[Cyrtopleura]]'' <small>Tryon, 1862</small>
** ''[[Cyrtopleura costata]]'' <small>([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>
* Genus ''[[Diplothyra]]'' <small>Tryon, 1862</small>
** ''[[Diplothyra smithii]]'' <small>Tryon, 1862</small>
* Genus ''[[Jouannetia]]'' <small>Desmoulins, 1828</small>
** ''[[Jouannetia quillingi]]'' <small>Turner, 1955</small>
* Genus ''[[Lignopholas]]'' <small>R. D. Turner, 1955</small>
** ''[[Lignopholas rivicola]]'' <small>(G. B. Sowerby II, 1849)</small>
* Genus ''[[Martesia (bivalve)|Martesia]]'' <small>G. B. Sowerby I, 1824</small>
** ''[[Martesia cuneiformis]]'' <small>([[Thomas Say|Say]], 1822)</small>
** ''[[Martesia fragilis]]'' <small>A. E. Verrill and Bush, 1890</small>
** ''[[Martesia striata]]'' <small>([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>
* Genus ''[[Netastoma]]'' <small>[[Phillip Pearsall Carpenter|Carpenter]], 1864</small>
** ''[[Netastoma darwinii]]'' <small>(Sowerby, 1849)</small>
** ''[[Netastoma japonicum]]'' <small>(Yokoyama, 1920)</small>
** ''[[Netastoma rostratum]]'' <small>([[Achille Valenciennes|Valenciennes]], 1846)</small>
* Genus ''[[Nipponopholas]]'' <small>Okamoto & Habe, 1987</small>
** ''[[Nipponopholas satoi]]'' <small>Okamoto & Habe, 1987</small>
* Genus ''[[Parapholas]]'' <small>Conrad, 1848</small>
** ''[[Parapholas californica]]'' <small>(Conrad, 1837)</small>
* Genus ''[[Penitella]]'' <small>[[Achille Valenciennes|Valenciennes]], 1846</small>
** ''[[Penitella conradi]]'' <small>[[Achille Valenciennes|Valenciennes]], 1846</small>
** ''[[Penitella fitchi]]'' <small>Turner, 1955</small>
** ''[[Penitella gabbii]]'' <small>(Tryon, 1863)</small>
** ''[[Penitella hopkinsi]]'' <small>Kennedy and Armentrout, 1989</small>
** ''[[Penitella kamakurensis]]'' <small>(Yokoyama, 1922)</small>
** ''[[Penitella penita]]'' <small>([[Timothy Abbott Conrad|Conrad]], 1837)</small>
** ''[[Penitella richardsoni]]'' <small>Kennedy, 1989</small>
** ''[[Penitella turnerae]]'' <small>Evans and Fisher, 1966</small>
* Genus ''[[Pholadidea]]'' <small>[[William Turton|Turton]], 1819</small>
** ''[[Pholadidea acherontea]]'' <small>Beu and Climo, 1974</small>
** ''[[Pholadidea loscombiana]]'' <small>[[William Turton|Turton]], 1819</small>
** ''[[Pholadidea spathulata]]'' <small>(Sowerby, 1850)</small>
** ''[[Pholadidea tridens]]'' <small>(Gray, 1843)</small>
* Genus ''[[Pholas]]'' <small>[[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]</small>
** ''[[Pholas campechiensis]]'' <small>[[Johann Friedrich Gmelin|Gmelin]], 1791</small>
** ''[[Pholas dactylus]]'' <small>[[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]</small> – common piddock
** ''[[Pholas orientalis]]'' <small>[[Johann Friedrich Gmelin|Gmelin]], 1791</small>
* Genus ''[[Talona (bivalve)|Talona]]'' <small>Gray, 1842</small>
** ''[[Talona explanata]]'' <small>(Spengler, 1792)</small>
* Genus ''[[Zirfaea]]'' <small>Gray, 1842</small>
** ''[[Zirfaea crispata]]'' <small>([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>
** ''[[Zirfaea pilsbryi]]'' <small>Lowe, 1931</small>
===Gallery===
<gallery>
Image:Fallen-angel-wing.jpg|Valves of the Atlantic mud-piddock or fallen angelwing, ''[[Barnea truncata]]''
Image:Piddocks 01 (pfly).jpg|[[Siphon (mollusc)|Siphons]] of the rough piddock, ''[[Zirfaea pilsbryi]]'' in [[Puget Sound]]
Image:Pholades niches.jpg|burrows, 2.5&nbsp;cm (1″) or less, in calcic rock, coast Boulogne - Calais (France)
Image:Angelwing burrow1.jpg|Angelwing and associated burrows
</gallery>
==See also==
* [[Pholad borings]]
==References==
{{Reflist}}
==External links==
{{Commons category|Pholadidae}}
* [http://www.mitchellspublications.com/guides/shells/articles/0018/ Angelwing]
* [http://www.sms.si.edu/IRLSpec/Cyrtop_costat.htm ''Cyrtopleura costata'' Angelwing clams]
* [http://www.ncseagrant.org/ NC Sea Grant ''Seashells of NC Field Guide'']
* [http://www.edwardtbabinski.us/beach_kids/sea_shells/angel_wings/ Angelwing, ''Cyrtopleura costata'']
* [http://www.sms.si.edu/IRLSpec/Cyrtop_costat.htm ''Cyrtopleura costata'' taxonomy]
* [https://www.itis.gov/servlet/SingleRpt/SingleRpt ITIS]
* [https://web.archive.org/web/20160918093945/http://www.biologie.uni-ulm.de/systax/daten/taxa/details/zoo_32.html]
{{Taxonbar|from=Q3015714}}
{{Authority control}}
[[Category:Pholadidae| ]]
[[Category:Bivalve families]]
[[Category:Taxa named by Jean-Baptiste Lamarck]]