Piddock
Encyclopedia
Pholadidae, known as piddocks or angelwings, are a family
of bivalve
mollusc
similar to a clam
; however, they 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
, crab
s 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.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of bivalve
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
similar to a clam
Clam
The word "clam" can be applied to freshwater mussels, and other freshwater bivalves, as well as marine bivalves.In the United States, "clam" can be used in several different ways: one, as a general term covering all bivalve molluscs...
; however, they 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
Siphon
The word siphon is sometimes used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in the English language today, the word siphon usually refers to a tube in an inverted U shape which causes a liquid to flow uphill, above the surface of the reservoir,...
exposed to take in water that it filters
Filter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
for food. When the piddock dies and leaves an empty tubular burrow, other marine life such as sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s 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
Red tide
Red tide is a common name for a phenomenon also known as an algal bloom , an event in which estuarine, marine, or fresh water algae accumulate rapidly in the water column and results in discoloration of the surface water. It is usually found in coastal areas...
algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
some may develop a pink coloration.
- The angelwing species Cyrtopleura costataCyrtopleura costataCyrtopleura costata or the angel wing clam is a bivalve mollusc in the family Pholadidae. It is found in shallow parts of the north west Atlantic living in the seabed where it burrows through sand and mud to a depth of up to .-Description:...
has approximately 26 radiating ribs. Growth lines run horizontally over the surface of the shell. Angelwings have a spoon-shaped brace under the beak of the shell, called the apophysis, where the mollusc's foot muscles are attached. Cyrtopleura costata possesses long siphons which protrude from its burrow and circulate water as the source for its food supply. It cannot retract its siphons into the protection of its shell, so the two valves can never shut completely. The muscles fusing the shell's valves together are weak, making it rare to find angelwings with both halves still intact. Some shell hunters dig for the living clam, and if dug up, the fragile shell must be placed immediately into a container of water or it will close and shatter. The angelwing's shell is popular with collectors, as well as a delicious food staple. The angelwing lives offshore and in estuaries, sometimes as much as a metre (three feet) deep in the mud or clay.
- 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 MaineMaineMaine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
to BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. 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 CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to UruguayUruguayUruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
.
- The common piddock (Pholas dactylusPholas dactylusPholas dactylus is a luminescent clam-like species, of the genus Pholas, found on the Pacific coast of South America. It bores into gneiss...
) is known for its bioluminescenceBioluminescenceBioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
and was investigated by Raphaël DuboisRaphaël DuboisHorace Raphael Dubois was a French pharmacologist known for his work on bioluminescence and anesthesia. He coined the terms proteon and bioproteon. Proteon means matter; bioroteon means living matter. He concluded that there is no difference between the two.-Reference:...
in his 1887 discovery of luciferinLuciferinLuciferins are a class of light-emitting biological pigments found in organisms that cause bioluminescence...
.
Genera and species
- Genus Barnea Risso, 1826
- Barnea candidaBarnea candidaBarnea candida is a marine bivalve mollusc in the family Pholadidae.-Description:The shell is long and covered in horizontal ribs, crossed by vertical ribs, forming a structure. On the intersections are scale formed spikes...
Linnaeus, 1758 - Barnea fragilis
- Barnea manilensis (PhilippiRodolfo Amando PhilippiRodolfo Amando Philippi was a German-Chilean paleontologist and zoologist....
, 1847) - Barnea parva Pennant, 1777
- Barnea similisBarnea similisBarnea similis, a rock borer or piddock, is a marine bivalve mollusc in the family Pholadidae.thumb|left|Barnea similis inside view, showing a shelly projection near the hinge-References:* Powell A. W...
(Gray, 1835) - Barnea subtruncata (G. B. Sowerby I, 1834)
- Barnea truncata (SayThomas SayThomas Say was an American naturalist, entomologist, malacologist, herpetologist and carcinologist. A taxonomist, he is often considered to be the father of descriptive entomology in the United States. He described more than 1,000 new species of beetles and over 400 species of insects of other...
, 1822)
- Barnea candida
- Genus Chaceia Turner, 1855
- Chaceia ovoidea (Gould, 1851)
- Genus Cyrtopleura Tryon, 1862
- Cyrtopleura costataCyrtopleura costataCyrtopleura costata or the angel wing clam is a bivalve mollusc in the family Pholadidae. It is found in shallow parts of the north west Atlantic living in the seabed where it burrows through sand and mud to a depth of up to .-Description:...
(Linnaeus, 1758)
- Cyrtopleura costata
- Genus Diplothyra Tryon, 1862
- Diplothyra smithii Tryon, 1862
- Genus Jouannetia Desmoulins, 1828
- Jouannetia quillingi Turner, 1955
- Genus Martesia G. B. Sowerby I, 1824
- Martesia cuneiformis (SayThomas SayThomas Say was an American naturalist, entomologist, malacologist, herpetologist and carcinologist. A taxonomist, he is often considered to be the father of descriptive entomology in the United States. He described more than 1,000 new species of beetles and over 400 species of insects of other...
, 1822) - Martesia fragilis A. E. Verrill and Bush, 1890
- Martesia striata (Linnaeus, 1758)
- Martesia cuneiformis (Say
- Genus Netastoma CarpenterPhillip Pearsall CarpenterPhilip Pearsall Carpenter Rev. Dr. , who in 1841, was ordained Presbyterian minister in England, and a Doctorate of Philosophy in 1860, and whose field work as a malacologist or conchologist in North America is still well regarded today...
, 1864- Netastoma japonicum (Yokoyama, 1920)
- Netastoma rostratum (ValenciennesAchille ValenciennesAchille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
, 1846)
- Genus Nettastomella CarpenterPhillip Pearsall CarpenterPhilip Pearsall Carpenter Rev. Dr. , who in 1841, was ordained Presbyterian minister in England, and a Doctorate of Philosophy in 1860, and whose field work as a malacologist or conchologist in North America is still well regarded today...
, 1865- Nettastomella darwini (Sowerby, 1849)
- Genus Parapholas Conrad, 1848
- Parapholas californica (Conrad, 1837)
- Genus Penitella ValenciennesAchille ValenciennesAchille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
, 1846- Penitella conradi ValenciennesAchille ValenciennesAchille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
, 1846 - Penitella fitchi Turner, 1955
- Penitella gabbii (Tryon, 1863)
- Penitella hopkinsi Kennedy and Armentrout, 1989
- Penitella kamakurensis (Yokoyama, 1922)
- Penitella penita (ConradTimothy Abbott ConradTimothy Abbott Conrad was an American geologist, malacologist and carcinologist.- External links :* at Internet Archive...
, 1837) - Penitella richardsoni Kennedy, 1989
- Penitella turnerae Evans and Fisher, 1966
- Penitella conradi Valenciennes
- Genus Pholadidea TurtonWilliam TurtonWilliam Turton was a British naturalist.Turton was born at Olveston, Gloucestershire and was educated at Oriel College, Oxford. He commenced in practice at Swansea, but devoted his leisure time to natural history, especially conchology...
, 1819- Pholadidea acherontea Beu and Climo, 1974
- Pholadidea loscombiana TurtonWilliam TurtonWilliam Turton was a British naturalist.Turton was born at Olveston, Gloucestershire and was educated at Oriel College, Oxford. He commenced in practice at Swansea, but devoted his leisure time to natural history, especially conchology...
, 1819 - Pholadidea spathulata (Sowerby, 1850)
- Pholadidea tridens (Gray, 1843)
- Genus Pholas Linnaeus, 1758
- Pholas campechiensis GmelinJohann Friedrich GmelinJohann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...
, 1791 - Pholas dactylusPholas dactylusPholas dactylus is a luminescent clam-like species, of the genus Pholas, found on the Pacific coast of South America. It bores into gneiss...
Linnaeus, 1758 – common piddock
- Pholas campechiensis Gmelin
- Genus Xylophaga TurtonWilliam TurtonWilliam Turton was a British naturalist.Turton was born at Olveston, Gloucestershire and was educated at Oriel College, Oxford. He commenced in practice at Swansea, but devoted his leisure time to natural history, especially conchology...
, 1822- Xylophaga abyssorum Dall, 1886
- Xylophaga atlantica Richards, 1942
- Xylophaga dorsalis (TurtonWilliam TurtonWilliam Turton was a British naturalist.Turton was born at Olveston, Gloucestershire and was educated at Oriel College, Oxford. He commenced in practice at Swansea, but devoted his leisure time to natural history, especially conchology...
, 1819) - Xylophaga praestans E. A. SmithEdgar Albert SmithEdgar Albert Smith was a British zoologist, a malacologist.His father was the Frederick Smith, a well-known entomologist, and Assistant Keeper of Zoology in the British Museum, Bloomsbury...
, 1903 - Xylophaga washingtona Bartsch, 1921
- Genus Xyloredo Turner, 1972
- Xyloredo naceli Turner, 1972
- Xyloredo nooi Turner, 1972
- Genus Zirfaea Gray, 1842
- Zirfaea crispata (Linnaeus, 1758)
- Zirfaea pilsbryi Lowe, 1931