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Wikipedia

Scallop

Scallop (/ˈskɒləp, ˈskæləp/)[a] is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily Pectinoidea, which also includes the thorny oysters.

Scallop
Temporal range: Middle Triassic-present 247–0 Ma
Argopecten irradians, the Atlantic bay scallop
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Pectinida
Superfamily: Pectinoidea
Family: Pectinidae
Wilkes, 1810
Genera

See text

Synonyms

Pectenidae

Scallops are a cosmopolitan family of bivalves found in all of the world's oceans, although never in fresh water. They are one of the very few groups of bivalves to be primarily "free-living", with many species capable of rapidly swimming short distances and even migrating some distance across the ocean floor. A small minority of scallop species live cemented to rocky substrates as adults, while others attach themselves to stationary or rooted objects such as seagrass at some point in their lives by means of a filament they secrete called a byssal thread. The majority of species, however, live recumbent on sandy substrates, and when they sense the presence of a predator such as a starfish, they may attempt to escape by swimming swiftly but erratically through the water using jet propulsion created by repeatedly clapping their shells together. Scallops have a well-developed nervous system, and unlike most other bivalves all scallops have a ring of numerous simple eyes situated around the edge of their mantles.

Many species of scallops are highly prized as a food source, and some are farmed as aquaculture. The word "scallop" is also applied to the meat of these bivalves, the adductor muscle, that is sold as seafood. The brightly coloured, symmetric, fan-shaped shells of scallops with their radiating and often fluted ornamentation are valued by shell collectors, and have been used since ancient times as motifs in art, architecture, and design.

Owing to their widespread distribution, scallop shells are a common sight on beaches and are often brightly coloured, making them a popular object to collect among beachcombers and vacationers.[2] The shells also have a significant place in popular culture.

Biology

Distribution and habitat

Scallops inhabit all the oceans of the world, with the largest number of species living in the Indo-Pacific region. Most species live in relatively shallow waters from the low tide line to 100 m, while others prefer much deeper water. Although some species only live in very narrow environments, most are opportunistic and can live under a wide variety of conditions. Scallops can be found living within, upon, or under either rocks, coral, rubble, sea grass, kelp, sand, or mud. Most scallops begin their lives as byssally attached juveniles, an ability that some retain throughout their lives while others grow into free-living adults.[3]

Anatomy and physiology

Very little variation occurs in the internal arrangement of organs and systems within the scallop family, and what follows can be taken to apply to the anatomy of any given scallop species.[4]

Orientation

 
Anatomical diagram of an Atlantic bay scallop with the left (i.e., upper) valve removed; anterior is to the left, posterior to the right

The shell of a scallop consists of two sides or valves, a left valve and a right one, divided by a plane of symmetry.[5] Most species of scallops rest on their right valve, and consequently, this valve is often deeper and more rounded than the left (i.e., upper) valve, which in many species is actually concave. With the hinge of the two valves oriented towards the top, one side corresponds to the animal's morphological anterior or front, the other is the posterior or rear, the hinge is the dorsal or back/top region, and the bottom corresponds to the ventral or (as it were) underside/belly.[6] However, as many scallop shells are more or less bilaterally symmetrical ("equivalved"), as well as symmetrical front/back ("equilateral"), determining which way a given animal is "facing" requires detailed information about its valves.[citation needed]

Valves

 
Diagram of a scallop with two differently sized valves shown positioned in ocean floor sediment: the right valve (shown at the bottom) much deeper than the left, allowing the scallop to appear less visible to predators

The model scallop shell consists of two similarly shaped valves with a straight hinge line along the top, devoid of teeth, and producing a pair of flat wings or "ears" (sometimes called "auricles", though this is also the term for two chambers in its heart) on either side of its midpoint, a feature which is unique to and apparent in all adult scallops.[7] These ears may be of similar size and shape, or the anterior ear may be somewhat larger (the posterior ear is never larger than the anterior one, an important feature for distinguishing which valve is which). As is the case in almost all bivalves, a series of lines and/or growth rings originates at the center of the hinge, at a spot called the "beak" surrounded by a generally raised area called the "umbo". These growth rings increase in size downwards until they reach the curved ventral edge of the shell. The shells of most scallops are streamlined to facilitate ease of movement during swimming at some point in their lifecycles, while also providing protection from predators. Scallops with ridged valves have the advantage of the architectural strength provided by these ridges called "ribs", although the ribs are somewhat costly in weight and mass. A unique feature of the scallop family is the presence, at some point during the animal's lifecycle, of a distinctive and taxonomically important shell feature, a comb-like structure called a ctenolium located on the anterior edge of the right valve next to the valve's byssal notch. Though many scallops lose this feature as they become free-swimming adults, all scallops have a ctenolium at some point during their lives, and no other bivalve has an analogous shell feature. The ctenolium is found in modern scallops only; both putative ancestors of modern scallops, the entoliids and the Aviculopectinidae, did not possess it.[8]

Muscular system

 
A live opened scallop showing the internal anatomy: The pale orange circular part is the adductor muscle; the darker orange curved part is the "coral", a culinary term for the ovary or roe.

Like the true oysters (family Ostreidae), scallops have a single central adductor muscle, thus, the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle. The adductor muscle of scallops is larger and more developed than those of oysters, because scallops are active swimmers; some species of scallops are known to move en masse from one area to another. In scallops, the shell shape tends to be highly regular, and is commonly used as an archetypal form of a seashell.[6]

Digestive system

Scallops are filter feeders, and eat plankton. Unlike many other bivalves, they lack siphons. Water moves over a filtering structure, where food particles become trapped in mucus. Next, the cilia on the structure move the food toward the mouth. Then, the food is digested in the digestive gland, an organ sometimes misleadingly referred to as the "liver, " which envelops part of the oesophagus, intestine, and entire stomach. Waste is passed on through the intestine (the terminus of which, like that of many mollusks, enters and leaves the animal's heart) and exits via the anus.[6]: p.20 

Nervous system

 
Neural map of a giant scallop

Like all bivalves, scallops lack actual brains. Instead, their nervous system is controlled by three paired ganglia located at various points throughout their anatomy, the cerebral or cerebropleural ganglia, the pedal ganglia, and the visceral or parietovisceral ganglia. All are yellowish. The visceral ganglia are by far the largest and most extensive of the three, and occur as an almost-fused mass near the center of the animal – proportionally, these are the largest and most intricate sets of ganglia of any modern bivalve. From this, radiate all of the nerves which connect the visceral ganglia to the circumpallial nerve ring which loops around the mantle and connects to all of the scallop's tentacles and eyes. This nerve ring is so well developed that, in some species, it may be legitimately considered an additional ganglion.[6]: p.46  The visceral ganglia are also the origin of the branchial nerves which control the scallop's gills. The cerebral ganglia are the next-largest set of ganglia and lie distinct from each other a significant distance dorsal to the visceral ganglia. They are attached to the visceral ganglia by long cerebral-visceral connectives, and to each other via a cerebral commissure that extends in an arch dorsally around the esophagus. The cerebral ganglia control the scallop's mouth via the palp nerves and connect to statocysts which help the animal sense its position in the surrounding environment. They are connected to the pedal ganglia by short cerebral-pedal connectives. The pedal ganglia, though not fused, are situated very close to each other near the midline. From the pedal ganglia, the scallop puts out pedal nerves which control the movement of, and sensation in, its small muscular foot.[6]: pp. 43–47 

Reproduction

The scallop family is unusual in that some members of the family are dioecious (males and females are separate), while others are simultaneous hermaphrodites (both sexes in the same individual), and a few are protoandrous hermaphrodites (males when young then switching to female). Red roe is that of a female, and white, is that of a male. Spermatozoa and ova are released freely into the water during mating season and fertilized ova sink to the bottom. After several weeks, the immature scallops hatch and the larvae, miniature transparent versions of the adults called "spat", drift in the plankton until settling to the bottom again (an event called spatfall) to grow, usually attaching by means of byssal threads. Some scallops, such as the Atlantic bay scallop Argopecten irradians, are short-lived, while others can live 20 years or more. Age can often be inferred from annuli, the concentric rings of their shells.[6]

Eyes

 
 
Closeups of the iridescent blue eyes of the bay scallop, Argopecten irradians[9]

Scallops have a large number (up to 200) of small (about 1 mm) eyes arranged along the edge of their mantles. These eyes represent a particular innovation among molluscs, relying on a concave, parabolic mirror of guanine crystals to focus and retro-reflect light instead of a lens as found in many other eye types.[10] Additionally, their eyes possess a double-layered retina, the outer retina responding most strongly to light and the inner to abrupt darkness.[11] While these eyes are unable to resolve shapes with high fidelity, the combined sensitivity of both retinas to light entering the eye and light retro-reflected from the mirror grants scallops exceptional contrast definition, as well as the ability to detect changing patterns of light and motion.[12][13] Scallops primarily rely on their eyes as an 'early-warning' threat detection system, scanning around them for movement and shadows which could potentially indicate predators. Additionally, some scallops alter their swimming or feeding behaviour based on the turbidity or clarity of the water, by detecting the movement of particulate matter in the water column.[14]

Adductor muscles

 
Adductor muscles of a scallop. a: photo in a live scallop. b: after removal of organs and tissues.

Scallops possess fast (striated) and slow (smooth) adductor muscles, which have different structures and contractile properties. These muscles lie closely apposed to one another but are divided by a connective tissue sheet. The striated adductor muscle contracts very quickly for swimming, whereas the smooth catch adductor muscle lacks striations, and contracts for long periods, keeping shells closed with little expenditure of energy.[15]

Locomotion

 
Overhead view of a scallop engaged in a zig-zag swimming motion
 
Overhead view of a scallop engaged in a unidirectional jumping motion

Scallops are mostly free-living and active, unlike the vast majority of bivalves, which are mostly slow-moving and infaunal. All scallops are thought to start out with a byssus, which attaches them to some form of substrate such as eelgrass when they are very young. Most species lose the byssus as they grow larger. A very few species go on to cement themselves to a hard substrate (e.g. Chlamys distorta and Hinnites multirigosus).[16]

However, the majority of scallops are free-living and can swim with brief bursts of speed to escape predators (mostly starfish) by rapidly opening and closing their valves. Indeed, everything about their characteristic shell shape – its symmetry, narrowness, smooth and/ or grooved surface, small flexible hinge, powerful adductor muscle, and continuous and uniformly curved edge – facilitates such activity. They often do this in spurts of several seconds before closing the shell entirely and sinking back to the bottom of their environment. Scallops are able to move through the water column either forward/ventrally (termed swimming) by sucking water in through the space between their valves, an area called the gape, and ejecting it through small holes near the hinge line called exhalant apertures, or backward/dorsally (termed jumping) by ejecting the water out the same way it came in (i.e. ventrally). A jumping scallop usually lands on the sea floor between each contraction of its valves, whereas a swimming scallop stays in the water column for most or all of its contractions and travels a much greater distance (though seldom at a height of more than 1 m off the sea bed and seldom for a distance of greater than 5 m).[16] Both jumping and swimming movements are very energy-intensive, and most scallops cannot perform more than four or five in a row before becoming completely exhausted and requiring several hours of rest. Should a swimming scallop land on its left side, it is capable of flipping itself over to its right side via a similar shell-clapping movement called the righting reflex. So-called singing scallops are rumored to make an audible, soft popping sound as they flap their shells underwater (though whether or not this happens is open to some debate).[17] Other scallops can extend their foot from between their valves, and by contracting the muscles in their foot, they can burrow into sand.[18]

Mobility and behavior

Most species of the scallop family are free-living, active swimmers, propelling themselves through the water through the adductor muscles to open and close their shells. Swimming occurs through the clapping of valves for water intake. Closing the valves propels water with a strong force near the hinge via the velum, a curtain-like fold of the mantle that directs water expulsion around the hinge. Scallops swim in the direction of the valve opening unless the velum directs an abrupt change in course direction.[19][20]

Other species of scallops can be found on the ocean floor attached to objects by byssal threads. Byssal threads are strong, silky fibers extending from the muscular foot, used to attach to a firm support, such as a rock. Some can also be found on the ocean floor, moving with an extendable foot between their valves or burrowing themselves in the sand by extending and retracting their feet.[6] Scallops are highly sensitive to shadows, vibrations, water movement, and chemical stimuli.[21] All possess a series of 100 blue eyes, embedded on the edge of the mantle of their upper and lower valves that can distinguish between light and darkness. They serve as a vital defense mechanism for avoiding predators. Though rather weak, their series of eyes can detect surrounding movement and alert precaution in the presence of predators, most commonly sea stars, crabs, and snails.[6] Physiological fitness and exercise of scallops decrease with age due to the decline of cellular and especially mitochondrial function,[22] thus increasing the risk of capture and lowering rates of survival. Older individuals show lower mitochondrial volume density and aerobic capacity, as well as decreased anaerobic capacity construed from the amount of glycogen stored in muscle tissue.[22] Environmental factors, such as changes in oxidative stress parameters, can inhibit the growth and development of scallops.[23]

Seasonal changes in temperature and food availability have been shown to affect muscle metabolic capabilities. The properties of mitochondria from the phasic adductor muscle of Euvola ziczac varied significantly during their annual reproductive cycle. Summer scallops in May have lower maximal oxidative capacities and substrate oxidation than any other time in the year. This phenomenon is due to lower protein levels in adductor muscles.[24]

Pearls

 
A scallop pearl

Scallops do occasionally produce pearls, though scallop pearls do not have the buildup of translucent layers or "nacre" which give desirability to the pearls of the feather oysters, and usually lack both lustre and iridescence. They can be dull, small, and of varying colour, but exceptions occur that are appreciated for their aesthetic qualities.[25]

Mutualism

Some scallops, including Chlamys hastata, frequently carry epibionts such as sponges and barnacles on their shells. The relationship of the sponge to the scallop is characterized as a form of mutualism, because the sponge provides protection by interfering with adhesion of predatory sea-star tube feet,[26][27][28] camouflages Chlamys hastata from predators,[27] or forms a physical barrier around byssal openings to prevent sea stars from inserting their digestive membranes.[28] Sponge encrustation protects C. hastata from barnacle larvae settlement, serving as a protection from epibionts that increase susceptibility to predators. Thus, barnacle larvae settlement occurs more frequently on sponge-free shells than on sponge-encrusted shells.[26]

In fact, barnacle encrustation negatively influences swimming in C. hastata. Those swimming with barnacle encrustation require more energy and show a detectable difference in anaerobic energy expenditure than those without encrustation. In the absence of barnacle encrustation, individual scallops swim significantly longer, travel further, and attain greater elevation.[29]

Lifecycle and growth

Many scallops are hermaphrodites (having female and male organs simultaneously), altering their sex throughout their lives, while others exist as dioecious species, having a definite sex. In this case, males are distinguished by roe-containing white testes and females with roe-containing orange ovaries. At the age of two, they usually become sexually active, but do not contribute significantly to egg production until four. The reproduction process occurs externally through spawning, in which eggs and sperm are released into the water. Spawning typically occurs in late summer and early autumn; spring spawning may also take place in the Mid-Atlantic Bight.[30] The females of scallops are highly fecund, capable of producing hundreds of millions of eggs per year.[30]

Once an egg is fertilized, it is then planktonic, a collection of microorganisms that drift abundantly in fresh or salt water. Larvae stay in the water column for four to seven weeks before dissipating to the ocean floor, where they attach themselves to objects through byssus threads. Byssus is eventually lost with adulthood, transitioning almost all scallop species into free swimmers. Rapid growth occurs within the first several years, with an increase of 50–80 % in shell height and quadrupled size in meat weight, and reaches a commercial size at about four to five years of age.[30] The lifespans of some scallops have been known to extend over 20 years.[31]

Taxonomy and phylogeny

Etymology

The family name Pectinidae, which is based on the name of the type genus, Pecten, comes from the Latin pecten meaning comb, in reference to a comb-like structure of the shell which is situated next to the byssal notch.[32]

Phylogeny

 
Fossil scallop Chlamys with encrusters; Nicosia Formation (Pliocene) of Cyprus

The fossil history of scallops is rich in species and specimens. The earliest known records of true scallops (those with a ctenolium) can be found from the Triassic period, over 200 million years ago.[8] The earliest species were divided into two groups, one with a nearly smooth exterior: Pleuronectis von Schlotheim, 1820, while the other had radial ribs or riblets and auricles: Praechlamys Allasinaz, 1972.[33] Fossil records also indicate that the abundance of species within the Pectinidae has varied greatly over time; Pectinidae was the most diverse bivalve family in the Mesozoic era, but the group almost disappeared completely by the end of the Cretaceous period. The survivors speciated rapidly during the Tertiary period. Nearly 7,000 species and subspecies names have been introduced for both fossil and recent Pectinidae.[34]

The cladogram is based on molecular phylogeny using mitochondrial (12S, 16S) and nuclear (18S, 28S, and H3) gene markers by Yaron Malkowsky and Annette Klussmann-Kolb in 2012.[35]

Pteriomorphia
(c. 247 mya) Pectinidae

Palliolinae (in part)  

Palliolinae (in part) and Camptonectinae

Chlamydinae  

(70 mya) Pecten  

Flexopecten  

(247 mya) Aequipecten  

Limidae (file shells)  

other Pteriomorphia (oysters, mussels)  

Taxonomic structure

Scallops are the family Pectinidae, marine bivalve molluscs within the superfamily Pectinoidea. Other families within this same superfamily share a somewhat similar overall shell shape, and some species within some of the related families are also commonly referred to as "scallops" (for example, Propeamussiidae, the glass scallops).

The family Pectinidae is the most diversified of the pectinoideans in present-day oceans. It is one of the largest marine bivalve families and contains over 300 extant species in 60 genera. Its origin dates back to the Middle Triassic Period, approximately 240 million years ago;[8] in terms of diversity, it has been a thriving family to the present day.[36]

Evolution from its origin has resulted in a successful and diverse group: pectinids are present in the world's seas, found in environments ranging from the intertidal zone to the hadal depths. The Pectinidae play an extremely important role in many benthic communities and exhibit a wide range of shell shapes, sizes, sculptures, and cultures.[37]

Raines and Poppe[b] listed nearly 900 species names of scallops, but most of these are considered either questionable or invalid. Raines and Poppe mentioned over 50 genera, around 250 species, and subspecies. Although species are generally well-circumscribed, their attribution to subfamilies and genera is sometimes equivocal, and information about phylogeny and relationships of the species are minimal, not the least because most work has been based only on adult morphology.[39]

This family's earliest and most comprehensive taxonomic treatments were based on macroscopic morphological characters of the adult shells and represent broadly divergent classification schemes.[40][41] Some level of taxonomic stability was achieved when Waller's studies in 1986, 1991, and 1993 concluded evolutionary relationships between pectinid taxa based on hypothesized morphological synapomorphies, which previous classification systems of Pectinidae failed to do. He created three Pectinidae subfamilies: Camptonectinidae, Chlamydinae and Pectininae.[42][43][44]

The framework of its phylogeny shows that repeated life habit states derive from evolutionary convergence and parallelism.[45][46] Studies have determined the family Pectinidae is monophyletic, developing from a single common ancestor. The direct ancestors of Pectinidae were scallop-like bivalves of the family Entoliidae.[47] Entoliids had auricles and a byssal notch only at youth, but they did not have a ctenolium, a comb-like arrangement along the margins of the byssal notch in Pectinidae. The ctenolium is the defining feature of the modern family Pectinidae and is a characteristic that has evolved within the lineage.[48]

In a 2008 paper, Puslednik et al. identified considerable convergence of shell morphology in a subset species of gliding Pectinidae, which suggests iterative morphological evolution may be more prevalent in the family than previously believed.[49]

There have been a number of efforts to address phylogenetic studies. Only three have assessed more than ten species[50][51][52] and only one has included multiple outgroups.[51] Nearly all previous molecular analyses of the Pectinidae have only utilized mitochondrial data. Phylogenies based only on mitochondrial sequence data do not always provide an accurate estimation on the species tree. Complicated factors can arise due to the presence of genetic polymorphisms in ancestral species and resultant lineage sorting.[53][54]

In molecular phylogenies of the Bivalvia, both the Spondylidae and the Propeamussiidae have been resolved as sister to the Pectinidae.[51][55]

List of subfamilies and genera

 
Pecten tigris Lamarck, 1819, museum specimens

The following are recognised in the family Pectinidae:

  • Subfamily Camptonectinae Habe, 1977[56]
    • Camptonectes Agassiz, 1864
    • Ciclopecten Seguenza, 1877
    • Delectopecten Stewart, 1920
    • Hyalopecten A. E. Verrill, 1897
    • Pseudohinnites Dijkstra, 1989
    • Sinepecten Schein, 2006
  • Subfamily Palliolinae Korbkov in Eberzin, 1960
    • Tribe Adamussiini Habe, 1977
      • Adamussium Thiele, 1934
      • Antarctipecten Beu & Taviani, 2013
      • Duplipecten Marwick, 1928
      • Lentipecten Marwick, 1928
      • Leoclunipecten Beu & Taviani, 2013
      • Ruthipecten Beu & Taviani, 2013
    • Tribe Eburneopectinini T. R. Waller, 2006
      • Eburneopecten Conrad, 1865
    • Tribe Mesopeplini T. R. Waller, 2006
      • Kaparachlamys Boreham, 1965
      • Mesopeplum Iredale, 1929
      • Phialopecten Marwick, 1928
      • Sectipecten Marwick, 1928
      • Towaipecten Beu, 1995
    • Tribe Palliolini Waller, 1993
    • Tribe Serripectinini T. R. Waller, 2006
      • Janupecten Marwick, 1928
      • Serripecten Marwick, 1928
  • Subfamily Pectininae
    • Tribe Aequipectinini F. Nordsieck, 1969
    • Tribe Amusiini Ridewood, 1903
    • Tribe Austrochlamydini Jonkers, 2003
      • Austrochlamys Jonkers, 2003
    • Tribe Decatopectinini Waller, 1986
      • Anguipecten Dall, Bartsch & Rehder, 1938
      • Antillipecten T. R. Waller, 2011 T. R. Waller, 2011
      • Bractechlamys Iredale, 1939
      • Decatopecten Rüppell in G. B. Sowerby II, 1839
      • Excellichlamys Iredale, 1939
      • Glorichlamys Dijkstra, 1991
      • Gloripallium Iredale, 1939
      • Juxtamusium Iredale, 1939
      • Lyropecten Conrad, 1862
      • Mirapecten Dall, Bartsch & Rehder, 1938
      • Nodipecten Dall, 1898
    • Tribe Pectinini Wilkes, 1810
      • Annachlamys Iredale, 1939
      • Fascipecten Freneix, Karache & Salvat 1971
      • Gigantopecten Rovereto, 1899
      • Minnivola Iredale, 1939
      • Oopecten Sacco, 1897
      • Oppenheimopecten Teppner, 1922
      • Pecten Müller, 1776
      • Serratovola Habe, 1951
  • Subfamily Pedinae Bronn, 1862
    • Tribe Chlamydini von Teppner, 1922
      • Austrohinnites Beu & Darragh, 2001
      • Azumapecten Habe, 1977
      • Chesapecten Ward & Blackwelder, 1975
      • Chlamys Röding, 1798
      • Chokekenia Santelli & del Río, 2018
      • Ckaraosippur Santelli & del Río, 2019
      • Complicachlamys Iredale, 1939
      • Coralichlamys Iredale, 1939
      • Dietotenhosen Santelli & del Río, 2019
      • Equichlamys Iredale, 1929
      • Hemipecten A. Adams & Reeve, 1849
      • Hinnites Deference, 1821
      • Laevichlamys Waller, 1993
      • Manupecten Monterosato, 1872
      • Moirechlamys Santelli & del Río, 2018
      • Notochlamys Cotton, 1930
      • Pascahinnites Dijkstra & Raines, 1999
      • Pixiechlamys Santelli & del Río, 2018
      • Praechlamys Allasinaz, 1972
      • Scaeochlamys Iredale, 1929
      • Semipallium Jousseaume in Lamy, 1928
      • Swiftopecten Hertlein, 1936
      • Talochlamys Iredale, 1929
      • Veprichlamys Iredale, 1929
      • Yabepecten Masuda, 1963
      • Zygochlamys Ihering, 1907
    • Tribe Crassadomini Waller, 1993
    • Tribe Fortipectinini Masuda, 1963
      • Fortipecten Yabe & Hatai, 1940
      • Kotorapecten Masuda, 1962
      • Masudapecten Akiyama, 1962
      • Mizuhopecten Masuda, 1963
      • Nipponopecten Masuda, 1962
      • Patinopecten Dall, 1898
    • Tribe Mimachlamydini Waller, 1993
    • Tribe Pedini Bronn, 1862
  • Subfamily incertae sedis
    • Agerchlamys Damborenea, 1993 †
    • Athlopecten Marwick, 1928 †
    • Camptochlamys Arkell, 1930 †
    • Indopecten Douglas, 1929 †
    • Jorgechlamys del Río, 2004 †
    • Lamellipecten Dijkstra & Maestrati, 2010
    • Lindapecten Petuch, 1995
    • Mixtipecten Marwick, 1928 †
    • Pseudopecten Bayle, 1878 †
 
Pearl nets used to grow spat to juveniles in scallop aquaculture

Seafood industry

Aquaculture

Wild fisheries

The largest wild scallop fishery is for the Atlantic sea scallop (Placopecten magellanicus) found off the northeastern United States and eastern Canada. Scallops are harvested using scallop dredges or bottom trawls. Most of the rest of the world's production of scallops is from Japan (wild, enhanced, and aquaculture) and China (mostly cultured Atlantic bay scallops).[57]: p.661 

In the D'Entrecasteaux Channel in the south of Tasmania dredging was banned in 1969, and since then divers have caught them in this area.[58] Attempts to use lighted pots to attract lobster and crab led to the discovery that they were effective in attracting scallops.[59]

Sustainability

The scallop fishery in New Zealand declined from a catch of 1246 tonnes in 1975 to 41 tonnes in 1980, at which point the government ordered the fishery closed. Spat seeding in the 1980s helped it recover, and catches in the 1990s were up to 684 tonnes.[60] The Tasman Bay / Te Tai-o-Aorere area was closed to commercial scallop harvesting from 2009 to 2011 due to a decline in the numbers. The commercial catch was down to 22 tonnes in 2015, and the fishery was closed again. The main causes for the decline seem to be fishing, climate effects, disease, pollutants, and sediment runoff from farming and forestry.[60] Forest and Bird list scallops as the "Worst Choice" in their Best Fish Guide for sustainable seafood species.[61][better source needed]

On the east coast of the United States, over the last 100 years, the populations of bay scallops have greatly diminished due to several factors but probably mostly due to a reduction in seagrasses (to which bay scallop spat attach) caused by increased coastal development and concomitant nutrient runoff. Another possible factor is the reduction of sharks from overfishing. A variety of sharks used to feed on rays, which are the main predator of bay scallops. With the shark population reduced – this apex predator in some places almost eliminated – the rays have been free to feed on scallops to greatly decrease their numbers.[62] By contrast, the Atlantic sea scallop (Placopecten magellanicus) is at historically high levels of abundance after recovery from overfishing.[63]

As food

 
Scallops with wine sauce

Scallops are characterized by offering two flavors and textures in one shell: the meat, called "scallop", which is firm and white, and the roe, called "coral", which is soft and often brightly coloured reddish-orange. Sometimes, markets sell scallops already prepared in the shell, with only the meat remaining. Outside the U.S., the scallop is often sold whole. They are available both with and without coral in the UK and Australia.[64]

Scallops without any additives are called "dry-packed", while scallops that are treated with sodium tripolyphosphate (STPP) are called "wet-packed". STPP causes the scallops to absorb moisture prior to the freezing process, thereby increasing their weight. The freezing process takes about two days.[65][better source needed]

In Galician cuisine, scallops are baked with breadcrumbs, ham, and onions.[citation needed] In Japanese cuisine, scallops may be served in soup or prepared as sashimi or sushi.[citation needed] In a sushi bar, hotategai (帆立貝, 海扇) is the traditional scallop on rice and, while kaibashira (貝柱) may be calscallop is more loosely used to include other shellfish species with round-shaped flesh (the adductor muscle), such as Atrina (帶子). Dried scallop is known in Cantonese Chinese cuisine as conpoy (乾瑤柱, 乾貝, 干貝).[citation needed] Smoked scallops are sometimes served as appetizers or used as an ingredient in the preparation of various dishes and appetizers.[66]

Scallops have lent their name to the culinary term "scalloped", which originally referred to seafood creamed and served hot in the shell.[67] Today, it means a creamed casserole dish such as scalloped potatoes, which contains no seafood at all.[citation needed]

Symbolism of the shell

Shell of Saint James

 
Shield with symbol of St. James the Great, Church of the Good Shepherd (Rosemont, Pennsylvania)

The scallop shell is the traditional emblem of St James the Great and is popular with pilgrims returning from the Way of St James (Camino de Santiago) and the apostle's shrine at Santiago de Compostela in Galicia, Spain.[68] Medieval Christians would collect a scallop shell while at Compostela as evidence of having made the journey. The association of Saint James with the scallop can most likely be traced to the legend that the apostle once rescued a knight covered in scallops.[69] An alternative version of the legend holds that while St. James' remains were being transported to Galicia (Spain) from Jerusalem, the disciples witnessed a bridegroom on horseback fall into the water and emerge covered in the shells.[70]

Indeed in French, the mollusc itself – as well as a popular preparation of it in cream sauce – is called coquille St. Jacques. In German they are Jakobsmuscheln – literally "James's shellfish". Curiously the Linnaean name Pecten jacobeus is given to the Mediterranean scallop, while the scallop endemic to Galicia is called Pecten maximus due to its bigger size.[71] The scallop shell is represented in the decoration of churches named after St. James, such as in St James' Church, Sydney, where it appears in a number of places, including in the mosaics on the floor of the chancel.[72]

When referring to St James, a scallop shell valve is displayed with its convex outer surface showing. In contrast, when the shell refers to the goddess Venus (see below), it is displayed with its concave interior surface showing.[71]

Shell of Saint Augustine

Saint Augustine is said to have been walking along the seashore, meditating on the unfathomable mystery of the Holy Trinity. A boy was using a shell to pour seawater into a little hole. When Augustine asked what he was doing, he replied, "I am emptying the sea into this hole." Thus did Augustine understand that man would never penetrate to the depths of the mystery of God.[73]

This symbolic meaning was taken up by Joseph Ratzinger in his coat of arms as Archbishop of Munich, and also retained by him when elected Pope Benedict XVI. While a doctoral candidate in 1953, Ratzinger wrote his dissertation on The People of God and the House of God in Augustine's Teaching, and the shell, therefore, has a personal connection with the thought of Saint Augustine.[73]

Badge

 
A scallop shell in a German coat of arms

The scallop shell symbol found its way into heraldry as a badge of those who had been on the pilgrimage to Compostela, although later, it became a symbol of pilgrimage in general. Winston Churchill and Diana, Princess of Wales' family, the Spencer family coat of arms includes a scallop, as well as both of Diana's sons Prince William, Duke of Cambridge and Prince Harry's personal coats of arms; also Pope Benedict XVI's personal coat of arms includes a scallop; another example is the surname Wilmot and also John Wesley's (which as a result the scallop shell is used as an emblem of Methodism). However, charges in heraldry do not always have an unvarying symbolic meaning, and there are cases of arms in which no family member went on a pilgrimage, and the occurrence of the scallop is simply a pun on the name of the armiger (as in the case of Jacques Coeur), or for other reasons.[74] In 1988, the State of New York in the US chose the bay scallop (Argopecten irradians) as its state shell.[75]

Fertility symbol

 
Aphrodite Anadyomene, from Amisos, 1st century BC – 1st century AD

Throughout antiquity, scallops and other hinged shells have symbolized the feminine principle.[76] Outwardly, the shell can symbolize the protective and nurturing principle, and inwardly, the "life-force slumbering within the Earth",[77] an emblem of the vulva.[78][79]

Many paintings of Venus, the Roman goddess of love and fertility, included a scallop shell in the painting to identify her. This is evident in Botticelli's classically inspired 15th century painting The Birth of Venus.[80]

One legend of the Way of St. James holds that the route was seen as a fertility pilgrimage, undertaken when a young couple desired to bear offspring. The scallop shell is believed to have originally been carried by pagans as a symbol of fertility.[81][82]

Other interpretations

Alternatively, the scallop resembles the setting sun, which was the focus of the pre-Christian Celtic rituals of the area.[citation needed] To wit, the pre-Christian roots of the Way of St. James was a Celtic death journey westwards towards the setting sun, terminating at the End of the World (Finisterra) on the "Coast of Death" (Costa da Morte) and the "Sea of Darkness" (i.e., the Abyss of Death, the Mare Tenebrosum, Latin for the Atlantic Ocean, itself named after the Dying Civilization of Atlantis).[83][better source needed]

Contemporary art

 
Large sculpture by Maggi Hambling titled The Scallop erected in 2003 on the beach at Aldeburgh, England

The beach at Aldeburgh, Suffolk, England, features Maggi Hambling's steel sculpture, The Scallop, erected in 2003 as a memorial to the composer Benjamin Britten, who had a long association with the town.[84]

See also

Explanatory notes

  1. ^ Also occasionally written scollop and once spelled scalap, -opp, scalop, skalop, scalepp, -oppe, scalloppe, skallap, -op, scallope, scallap, s(c)kollop, and scollup, -op as well as escallop, escalop, and escollop, though scallop appears to have become the dominant way of spelling the word in English.[1]
  2. ^ Raines, B. K. & Poppe, G. T. (2006): The Family Pectinidae.[38]

Citations

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  2. ^ Robinson & Robinson 2000, p. 65.
  3. ^ Shumway & Parsons 2011, p. 207.
  4. ^ Shumway & Parsons 2011, p. 124.
  5. ^ Milsom & Rigby 2009, p. 62.
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  7. ^ Shumway & Parsons 2011, p. 59.
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General bibliography

External links

scallop, verb, senses, potato, scallops, potato, cake, scalloped, potatoes, gratin, potatoes, gratiné, meat, escalope, scallop, shell, moth, rheumaptera, undulata, common, name, that, encompasses, various, species, marine, bivalve, mollusks, taxonomic, family,. For verb senses see Scalloping For potato scallops see Potato cake For scalloped potatoes see Gratin Potatoes gratine For the cut of meat see Escalope For the scallop shell moth see Rheumaptera undulata Scallop ˈ s k ɒ l e p ˈ s k ae l e p a is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae the scallops However the common name scallop is also sometimes applied to species in other closely related families within the superfamily Pectinoidea which also includes the thorny oysters ScallopTemporal range Middle Triassic present 247 0 Ma PreꞒ Ꞓ O S D C P T J K Pg NArgopecten irradians the Atlantic bay scallopScientific classificationKingdom AnimaliaPhylum MolluscaClass BivalviaOrder PectinidaSuperfamily PectinoideaFamily PectinidaeWilkes 1810GeneraSee textSynonymsPectenidaeScallops are a cosmopolitan family of bivalves found in all of the world s oceans although never in fresh water They are one of the very few groups of bivalves to be primarily free living with many species capable of rapidly swimming short distances and even migrating some distance across the ocean floor A small minority of scallop species live cemented to rocky substrates as adults while others attach themselves to stationary or rooted objects such as seagrass at some point in their lives by means of a filament they secrete called a byssal thread The majority of species however live recumbent on sandy substrates and when they sense the presence of a predator such as a starfish they may attempt to escape by swimming swiftly but erratically through the water using jet propulsion created by repeatedly clapping their shells together Scallops have a well developed nervous system and unlike most other bivalves all scallops have a ring of numerous simple eyes situated around the edge of their mantles Many species of scallops are highly prized as a food source and some are farmed as aquaculture The word scallop is also applied to the meat of these bivalves the adductor muscle that is sold as seafood The brightly coloured symmetric fan shaped shells of scallops with their radiating and often fluted ornamentation are valued by shell collectors and have been used since ancient times as motifs in art architecture and design Owing to their widespread distribution scallop shells are a common sight on beaches and are often brightly coloured making them a popular object to collect among beachcombers and vacationers 2 The shells also have a significant place in popular culture Contents 1 Biology 1 1 Distribution and habitat 1 2 Anatomy and physiology 1 2 1 Orientation 1 2 2 Valves 1 2 3 Muscular system 1 2 4 Digestive system 1 2 5 Nervous system 1 2 6 Reproduction 1 2 7 Eyes 1 2 8 Adductor muscles 1 2 9 Locomotion 1 2 10 Mobility and behavior 1 2 11 Pearls 1 2 12 Mutualism 1 2 13 Lifecycle and growth 1 3 Taxonomy and phylogeny 1 3 1 Etymology 1 3 2 Phylogeny 1 3 3 Taxonomic structure 1 3 4 List of subfamilies and genera 2 Seafood industry 2 1 Aquaculture 2 2 Wild fisheries 2 3 Sustainability 3 As food 4 Symbolism of the shell 4 1 Shell of Saint James 4 2 Shell of Saint Augustine 4 3 Badge 4 4 Fertility symbol 4 5 Other interpretations 4 6 Contemporary art 5 See also 6 Explanatory notes 7 Citations 8 General bibliography 9 External linksBiology EditDistribution and habitat Edit Scallops inhabit all the oceans of the world with the largest number of species living in the Indo Pacific region Most species live in relatively shallow waters from the low tide line to 100 m while others prefer much deeper water Although some species only live in very narrow environments most are opportunistic and can live under a wide variety of conditions Scallops can be found living within upon or under either rocks coral rubble sea grass kelp sand or mud Most scallops begin their lives as byssally attached juveniles an ability that some retain throughout their lives while others grow into free living adults 3 Anatomy and physiology Edit Very little variation occurs in the internal arrangement of organs and systems within the scallop family and what follows can be taken to apply to the anatomy of any given scallop species 4 Orientation Edit Anatomical diagram of an Atlantic bay scallop with the left i e upper valve removed anterior is to the left posterior to the right The shell of a scallop consists of two sides or valves a left valve and a right one divided by a plane of symmetry 5 Most species of scallops rest on their right valve and consequently this valve is often deeper and more rounded than the left i e upper valve which in many species is actually concave With the hinge of the two valves oriented towards the top one side corresponds to the animal s morphological anterior or front the other is the posterior or rear the hinge is the dorsal or back top region and the bottom corresponds to the ventral or as it were underside belly 6 However as many scallop shells are more or less bilaterally symmetrical equivalved as well as symmetrical front back equilateral determining which way a given animal is facing requires detailed information about its valves citation needed Valves Edit Diagram of a scallop with two differently sized valves shown positioned in ocean floor sediment the right valve shown at the bottom much deeper than the left allowing the scallop to appear less visible to predators The model scallop shell consists of two similarly shaped valves with a straight hinge line along the top devoid of teeth and producing a pair of flat wings or ears sometimes called auricles though this is also the term for two chambers in its heart on either side of its midpoint a feature which is unique to and apparent in all adult scallops 7 These ears may be of similar size and shape or the anterior ear may be somewhat larger the posterior ear is never larger than the anterior one an important feature for distinguishing which valve is which As is the case in almost all bivalves a series of lines and or growth rings originates at the center of the hinge at a spot called the beak surrounded by a generally raised area called the umbo These growth rings increase in size downwards until they reach the curved ventral edge of the shell The shells of most scallops are streamlined to facilitate ease of movement during swimming at some point in their lifecycles while also providing protection from predators Scallops with ridged valves have the advantage of the architectural strength provided by these ridges called ribs although the ribs are somewhat costly in weight and mass A unique feature of the scallop family is the presence at some point during the animal s lifecycle of a distinctive and taxonomically important shell feature a comb like structure called a ctenolium located on the anterior edge of the right valve next to the valve s byssal notch Though many scallops lose this feature as they become free swimming adults all scallops have a ctenolium at some point during their lives and no other bivalve has an analogous shell feature The ctenolium is found in modern scallops only both putative ancestors of modern scallops the entoliids and the Aviculopectinidae did not possess it 8 Muscular system Edit A live opened scallop showing the internal anatomy The pale orange circular part is the adductor muscle the darker orange curved part is the coral a culinary term for the ovary or roe Like the true oysters family Ostreidae scallops have a single central adductor muscle thus the inside of their shells has a characteristic central scar marking the point of attachment for this muscle The adductor muscle of scallops is larger and more developed than those of oysters because scallops are active swimmers some species of scallops are known to move en masse from one area to another In scallops the shell shape tends to be highly regular and is commonly used as an archetypal form of a seashell 6 Digestive system Edit Scallops are filter feeders and eat plankton Unlike many other bivalves they lack siphons Water moves over a filtering structure where food particles become trapped in mucus Next the cilia on the structure move the food toward the mouth Then the food is digested in the digestive gland an organ sometimes misleadingly referred to as the liver which envelops part of the oesophagus intestine and entire stomach Waste is passed on through the intestine the terminus of which like that of many mollusks enters and leaves the animal s heart and exits via the anus 6 p 20 Nervous system Edit Neural map of a giant scallop Like all bivalves scallops lack actual brains Instead their nervous system is controlled by three paired ganglia located at various points throughout their anatomy the cerebral or cerebropleural ganglia the pedal ganglia and the visceral or parietovisceral ganglia All are yellowish The visceral ganglia are by far the largest and most extensive of the three and occur as an almost fused mass near the center of the animal proportionally these are the largest and most intricate sets of ganglia of any modern bivalve From this radiate all of the nerves which connect the visceral ganglia to the circumpallial nerve ring which loops around the mantle and connects to all of the scallop s tentacles and eyes This nerve ring is so well developed that in some species it may be legitimately considered an additional ganglion 6 p 46 The visceral ganglia are also the origin of the branchial nerves which control the scallop s gills The cerebral ganglia are the next largest set of ganglia and lie distinct from each other a significant distance dorsal to the visceral ganglia They are attached to the visceral ganglia by long cerebral visceral connectives and to each other via a cerebral commissure that extends in an arch dorsally around the esophagus The cerebral ganglia control the scallop s mouth via the palp nerves and connect to statocysts which help the animal sense its position in the surrounding environment They are connected to the pedal ganglia by short cerebral pedal connectives The pedal ganglia though not fused are situated very close to each other near the midline From the pedal ganglia the scallop puts out pedal nerves which control the movement of and sensation in its small muscular foot 6 pp 43 47 Reproduction Edit The scallop family is unusual in that some members of the family are dioecious males and females are separate while others are simultaneous hermaphrodites both sexes in the same individual and a few are protoandrous hermaphrodites males when young then switching to female Red roe is that of a female and white is that of a male Spermatozoa and ova are released freely into the water during mating season and fertilized ova sink to the bottom After several weeks the immature scallops hatch and the larvae miniature transparent versions of the adults called spat drift in the plankton until settling to the bottom again an event called spatfall to grow usually attaching by means of byssal threads Some scallops such as the Atlantic bay scallop Argopecten irradians are short lived while others can live 20 years or more Age can often be inferred from annuli the concentric rings of their shells 6 Eyes Edit Closeups of the iridescent blue eyes of the bay scallop Argopecten irradians 9 Scallops have a large number up to 200 of small about 1 mm eyes arranged along the edge of their mantles These eyes represent a particular innovation among molluscs relying on a concave parabolic mirror of guanine crystals to focus and retro reflect light instead of a lens as found in many other eye types 10 Additionally their eyes possess a double layered retina the outer retina responding most strongly to light and the inner to abrupt darkness 11 While these eyes are unable to resolve shapes with high fidelity the combined sensitivity of both retinas to light entering the eye and light retro reflected from the mirror grants scallops exceptional contrast definition as well as the ability to detect changing patterns of light and motion 12 13 Scallops primarily rely on their eyes as an early warning threat detection system scanning around them for movement and shadows which could potentially indicate predators Additionally some scallops alter their swimming or feeding behaviour based on the turbidity or clarity of the water by detecting the movement of particulate matter in the water column 14 Adductor muscles Edit Adductor muscles of a scallop a photo in a live scallop b after removal of organs and tissues Scallops possess fast striated and slow smooth adductor muscles which have different structures and contractile properties These muscles lie closely apposed to one another but are divided by a connective tissue sheet The striated adductor muscle contracts very quickly for swimming whereas the smooth catch adductor muscle lacks striations and contracts for long periods keeping shells closed with little expenditure of energy 15 Locomotion Edit Overhead view of a scallop engaged in a zig zag swimming motion Overhead view of a scallop engaged in a unidirectional jumping motion Scallops are mostly free living and active unlike the vast majority of bivalves which are mostly slow moving and infaunal All scallops are thought to start out with a byssus which attaches them to some form of substrate such as eelgrass when they are very young Most species lose the byssus as they grow larger A very few species go on to cement themselves to a hard substrate e g Chlamys distorta and Hinnites multirigosus 16 However the majority of scallops are free living and can swim with brief bursts of speed to escape predators mostly starfish by rapidly opening and closing their valves Indeed everything about their characteristic shell shape its symmetry narrowness smooth and or grooved surface small flexible hinge powerful adductor muscle and continuous and uniformly curved edge facilitates such activity They often do this in spurts of several seconds before closing the shell entirely and sinking back to the bottom of their environment Scallops are able to move through the water column either forward ventrally termed swimming by sucking water in through the space between their valves an area called the gape and ejecting it through small holes near the hinge line called exhalant apertures or backward dorsally termed jumping by ejecting the water out the same way it came in i e ventrally A jumping scallop usually lands on the sea floor between each contraction of its valves whereas a swimming scallop stays in the water column for most or all of its contractions and travels a much greater distance though seldom at a height of more than 1 m off the sea bed and seldom for a distance of greater than 5 m 16 Both jumping and swimming movements are very energy intensive and most scallops cannot perform more than four or five in a row before becoming completely exhausted and requiring several hours of rest Should a swimming scallop land on its left side it is capable of flipping itself over to its right side via a similar shell clapping movement called the righting reflex So called singing scallops are rumored to make an audible soft popping sound as they flap their shells underwater though whether or not this happens is open to some debate 17 Other scallops can extend their foot from between their valves and by contracting the muscles in their foot they can burrow into sand 18 Mobility and behavior Edit Most species of the scallop family are free living active swimmers propelling themselves through the water through the adductor muscles to open and close their shells Swimming occurs through the clapping of valves for water intake Closing the valves propels water with a strong force near the hinge via the velum a curtain like fold of the mantle that directs water expulsion around the hinge Scallops swim in the direction of the valve opening unless the velum directs an abrupt change in course direction 19 20 Other species of scallops can be found on the ocean floor attached to objects by byssal threads Byssal threads are strong silky fibers extending from the muscular foot used to attach to a firm support such as a rock Some can also be found on the ocean floor moving with an extendable foot between their valves or burrowing themselves in the sand by extending and retracting their feet 6 Scallops are highly sensitive to shadows vibrations water movement and chemical stimuli 21 All possess a series of 100 blue eyes embedded on the edge of the mantle of their upper and lower valves that can distinguish between light and darkness They serve as a vital defense mechanism for avoiding predators Though rather weak their series of eyes can detect surrounding movement and alert precaution in the presence of predators most commonly sea stars crabs and snails 6 Physiological fitness and exercise of scallops decrease with age due to the decline of cellular and especially mitochondrial function 22 thus increasing the risk of capture and lowering rates of survival Older individuals show lower mitochondrial volume density and aerobic capacity as well as decreased anaerobic capacity construed from the amount of glycogen stored in muscle tissue 22 Environmental factors such as changes in oxidative stress parameters can inhibit the growth and development of scallops 23 Seasonal changes in temperature and food availability have been shown to affect muscle metabolic capabilities The properties of mitochondria from the phasic adductor muscle of Euvola ziczac varied significantly during their annual reproductive cycle Summer scallops in May have lower maximal oxidative capacities and substrate oxidation than any other time in the year This phenomenon is due to lower protein levels in adductor muscles 24 Pearls Edit A scallop pearl Scallops do occasionally produce pearls though scallop pearls do not have the buildup of translucent layers or nacre which give desirability to the pearls of the feather oysters and usually lack both lustre and iridescence They can be dull small and of varying colour but exceptions occur that are appreciated for their aesthetic qualities 25 Mutualism Edit Some scallops including Chlamys hastata frequently carry epibionts such as sponges and barnacles on their shells The relationship of the sponge to the scallop is characterized as a form of mutualism because the sponge provides protection by interfering with adhesion of predatory sea star tube feet 26 27 28 camouflages Chlamys hastata from predators 27 or forms a physical barrier around byssal openings to prevent sea stars from inserting their digestive membranes 28 Sponge encrustation protects C hastata from barnacle larvae settlement serving as a protection from epibionts that increase susceptibility to predators Thus barnacle larvae settlement occurs more frequently on sponge free shells than on sponge encrusted shells 26 In fact barnacle encrustation negatively influences swimming in C hastata Those swimming with barnacle encrustation require more energy and show a detectable difference in anaerobic energy expenditure than those without encrustation In the absence of barnacle encrustation individual scallops swim significantly longer travel further and attain greater elevation 29 Lifecycle and growth Edit Many scallops are hermaphrodites having female and male organs simultaneously altering their sex throughout their lives while others exist as dioecious species having a definite sex In this case males are distinguished by roe containing white testes and females with roe containing orange ovaries At the age of two they usually become sexually active but do not contribute significantly to egg production until four The reproduction process occurs externally through spawning in which eggs and sperm are released into the water Spawning typically occurs in late summer and early autumn spring spawning may also take place in the Mid Atlantic Bight 30 The females of scallops are highly fecund capable of producing hundreds of millions of eggs per year 30 Once an egg is fertilized it is then planktonic a collection of microorganisms that drift abundantly in fresh or salt water Larvae stay in the water column for four to seven weeks before dissipating to the ocean floor where they attach themselves to objects through byssus threads Byssus is eventually lost with adulthood transitioning almost all scallop species into free swimmers Rapid growth occurs within the first several years with an increase of 50 80 in shell height and quadrupled size in meat weight and reaches a commercial size at about four to five years of age 30 The lifespans of some scallops have been known to extend over 20 years 31 Taxonomy and phylogeny Edit Etymology Edit The family name Pectinidae which is based on the name of the type genus Pecten comes from the Latin pecten meaning comb in reference to a comb like structure of the shell which is situated next to the byssal notch 32 Phylogeny Edit Fossil scallop Chlamys with encrusters Nicosia Formation Pliocene of Cyprus The fossil history of scallops is rich in species and specimens The earliest known records of true scallops those with a ctenolium can be found from the Triassic period over 200 million years ago 8 The earliest species were divided into two groups one with a nearly smooth exterior Pleuronectis von Schlotheim 1820 while the other had radial ribs or riblets and auricles Praechlamys Allasinaz 1972 33 Fossil records also indicate that the abundance of species within the Pectinidae has varied greatly over time Pectinidae was the most diverse bivalve family in the Mesozoic era but the group almost disappeared completely by the end of the Cretaceous period The survivors speciated rapidly during the Tertiary period Nearly 7 000 species and subspecies names have been introduced for both fossil and recent Pectinidae 34 The cladogram is based on molecular phylogeny using mitochondrial 12S 16S and nuclear 18S 28S and H3 gene markers by Yaron Malkowsky and Annette Klussmann Kolb in 2012 35 Pteriomorphia c 247 mya Pectinidae Palliolinae in part Palliolinae in part and CamptonectinaeChlamydinae 70 mya Pecten Flexopecten 247 mya Aequipecten Limidae file shells other Pteriomorphia oysters mussels Taxonomic structure Edit Scallops are the family Pectinidae marine bivalve molluscs within the superfamily Pectinoidea Other families within this same superfamily share a somewhat similar overall shell shape and some species within some of the related families are also commonly referred to as scallops for example Propeamussiidae the glass scallops The family Pectinidae is the most diversified of the pectinoideans in present day oceans It is one of the largest marine bivalve families and contains over 300 extant species in 60 genera Its origin dates back to the Middle Triassic Period approximately 240 million years ago 8 in terms of diversity it has been a thriving family to the present day 36 Evolution from its origin has resulted in a successful and diverse group pectinids are present in the world s seas found in environments ranging from the intertidal zone to the hadal depths The Pectinidae play an extremely important role in many benthic communities and exhibit a wide range of shell shapes sizes sculptures and cultures 37 Raines and Poppe b listed nearly 900 species names of scallops but most of these are considered either questionable or invalid Raines and Poppe mentioned over 50 genera around 250 species and subspecies Although species are generally well circumscribed their attribution to subfamilies and genera is sometimes equivocal and information about phylogeny and relationships of the species are minimal not the least because most work has been based only on adult morphology 39 This family s earliest and most comprehensive taxonomic treatments were based on macroscopic morphological characters of the adult shells and represent broadly divergent classification schemes 40 41 Some level of taxonomic stability was achieved when Waller s studies in 1986 1991 and 1993 concluded evolutionary relationships between pectinid taxa based on hypothesized morphological synapomorphies which previous classification systems of Pectinidae failed to do He created three Pectinidae subfamilies Camptonectinidae Chlamydinae and Pectininae 42 43 44 The framework of its phylogeny shows that repeated life habit states derive from evolutionary convergence and parallelism 45 46 Studies have determined the family Pectinidae is monophyletic developing from a single common ancestor The direct ancestors of Pectinidae were scallop like bivalves of the family Entoliidae 47 Entoliids had auricles and a byssal notch only at youth but they did not have a ctenolium a comb like arrangement along the margins of the byssal notch in Pectinidae The ctenolium is the defining feature of the modern family Pectinidae and is a characteristic that has evolved within the lineage 48 In a 2008 paper Puslednik et al identified considerable convergence of shell morphology in a subset species of gliding Pectinidae which suggests iterative morphological evolution may be more prevalent in the family than previously believed 49 There have been a number of efforts to address phylogenetic studies Only three have assessed more than ten species 50 51 52 and only one has included multiple outgroups 51 Nearly all previous molecular analyses of the Pectinidae have only utilized mitochondrial data Phylogenies based only on mitochondrial sequence data do not always provide an accurate estimation on the species tree Complicated factors can arise due to the presence of genetic polymorphisms in ancestral species and resultant lineage sorting 53 54 In molecular phylogenies of the Bivalvia both the Spondylidae and the Propeamussiidae have been resolved as sister to the Pectinidae 51 55 List of subfamilies and genera Edit Bractechlamys vexillum Pecten tigris Lamarck 1819 museum specimens The following are recognised in the family Pectinidae Subfamily Camptonectinae Habe 1977 56 Camptonectes Agassiz 1864 Ciclopecten Seguenza 1877 Delectopecten Stewart 1920 Hyalopecten A E Verrill 1897 Pseudohinnites Dijkstra 1989 Sinepecten Schein 2006 Subfamily Palliolinae Korbkov in Eberzin 1960 Tribe Adamussiini Habe 1977 Adamussium Thiele 1934 Antarctipecten Beu amp Taviani 2013 Duplipecten Marwick 1928 Lentipecten Marwick 1928 Leoclunipecten Beu amp Taviani 2013 Ruthipecten Beu amp Taviani 2013 Tribe Eburneopectinini T R Waller 2006 Eburneopecten Conrad 1865 Tribe Mesopeplini T R Waller 2006 Kaparachlamys Boreham 1965 Mesopeplum Iredale 1929 Phialopecten Marwick 1928 Sectipecten Marwick 1928 Towaipecten Beu 1995 Tribe Palliolini Waller 1993 Karnekampia H P Wagner 1988 Lissochlamys Sacco 1897 Palliolum Monterosato 1884 Placopecten Verrill 1897 Pseudamussium Morch 1853 Tribe Serripectinini T R Waller 2006 Janupecten Marwick 1928 Serripecten Marwick 1928 Subfamily Pectininae Tribe Aequipectinini F Nordsieck 1969 Aequipecten P Fischer 1886 Argopecten Monterosato 1889 Cryptopecten Dall Bartsch amp Rehder 1938 Flexopecten Sacco 1897 Haumea Dall Bartsch amp Rehder 1938 Leptopecten Verrill 1897 Volachlamys Iredale 1939 Tribe Amusiini Ridewood 1903 Amusium Roding 1798 Dentamussium Dijkstra 1990 Euvola Dall 1898 Leopecten Masuda 1971 Ylistrum Mynhardt amp Alejandrino 2014 Tribe Austrochlamydini Jonkers 2003 Austrochlamys Jonkers 2003 Tribe Decatopectinini Waller 1986 Anguipecten Dall Bartsch amp Rehder 1938 Antillipecten T R Waller 2011 T R Waller 2011 Bractechlamys Iredale 1939 Decatopecten Ruppell in G B Sowerby II 1839 Excellichlamys Iredale 1939 Glorichlamys Dijkstra 1991 Gloripallium Iredale 1939 Juxtamusium Iredale 1939 Lyropecten Conrad 1862 Mirapecten Dall Bartsch amp Rehder 1938 Nodipecten Dall 1898 Tribe Pectinini Wilkes 1810 Annachlamys Iredale 1939 Fascipecten Freneix Karache amp Salvat 1971 Gigantopecten Rovereto 1899 Minnivola Iredale 1939 Oopecten Sacco 1897 Oppenheimopecten Teppner 1922 Pecten Muller 1776 Serratovola Habe 1951 Subfamily Pedinae Bronn 1862 Tribe Chlamydini von Teppner 1922 Austrohinnites Beu amp Darragh 2001 Azumapecten Habe 1977 Chesapecten Ward amp Blackwelder 1975 Chlamys Roding 1798 Chokekenia Santelli amp del Rio 2018 Ckaraosippur Santelli amp del Rio 2019 Complicachlamys Iredale 1939 Coralichlamys Iredale 1939 Dietotenhosen Santelli amp del Rio 2019 Equichlamys Iredale 1929 Hemipecten A Adams amp Reeve 1849 Hinnites Deference 1821 Laevichlamys Waller 1993 Manupecten Monterosato 1872 Moirechlamys Santelli amp del Rio 2018 Notochlamys Cotton 1930 Pascahinnites Dijkstra amp Raines 1999 Pixiechlamys Santelli amp del Rio 2018 Praechlamys Allasinaz 1972 Scaeochlamys Iredale 1929 Semipallium Jousseaume in Lamy 1928 Swiftopecten Hertlein 1936 Talochlamys Iredale 1929 Veprichlamys Iredale 1929 Yabepecten Masuda 1963 Zygochlamys Ihering 1907 Tribe Crassadomini Waller 1993 Caribachlamys Waller 1993 Crassadoma Bernard 1986 Tribe Fortipectinini Masuda 1963 Fortipecten Yabe amp Hatai 1940 Kotorapecten Masuda 1962 Masudapecten Akiyama 1962 Mizuhopecten Masuda 1963 Nipponopecten Masuda 1962 Patinopecten Dall 1898 Tribe Mimachlamydini Waller 1993 Mimachlamys Iredale 1929 Spathochlamys Waller 1993 Tribe Pedini Bronn 1862 Pedum Bruguiere 1792 Subfamily incertae sedis Agerchlamys Damborenea 1993 Athlopecten Marwick 1928 Camptochlamys Arkell 1930 Indopecten Douglas 1929 Jorgechlamys del Rio 2004 Lamellipecten Dijkstra amp Maestrati 2010 Lindapecten Petuch 1995 Mixtipecten Marwick 1928 Pseudopecten Bayle 1878 Pearl nets used to grow spat to juveniles in scallop aquacultureSeafood industry EditAquaculture Edit Main article Scallop aquaculture Wild fisheries Edit The largest wild scallop fishery is for the Atlantic sea scallop Placopecten magellanicus found off the northeastern United States and eastern Canada Scallops are harvested using scallop dredges or bottom trawls Most of the rest of the world s production of scallops is from Japan wild enhanced and aquaculture and China mostly cultured Atlantic bay scallops 57 p 661 In the D Entrecasteaux Channel in the south of Tasmania dredging was banned in 1969 and since then divers have caught them in this area 58 Attempts to use lighted pots to attract lobster and crab led to the discovery that they were effective in attracting scallops 59 Sustainability Edit The scallop fishery in New Zealand declined from a catch of 1246 tonnes in 1975 to 41 tonnes in 1980 at which point the government ordered the fishery closed Spat seeding in the 1980s helped it recover and catches in the 1990s were up to 684 tonnes 60 The Tasman Bay Te Tai o Aorere area was closed to commercial scallop harvesting from 2009 to 2011 due to a decline in the numbers The commercial catch was down to 22 tonnes in 2015 and the fishery was closed again The main causes for the decline seem to be fishing climate effects disease pollutants and sediment runoff from farming and forestry 60 Forest and Bird list scallops as the Worst Choice in their Best Fish Guide for sustainable seafood species 61 better source needed On the east coast of the United States over the last 100 years the populations of bay scallops have greatly diminished due to several factors but probably mostly due to a reduction in seagrasses to which bay scallop spat attach caused by increased coastal development and concomitant nutrient runoff Another possible factor is the reduction of sharks from overfishing A variety of sharks used to feed on rays which are the main predator of bay scallops With the shark population reduced this apex predator in some places almost eliminated the rays have been free to feed on scallops to greatly decrease their numbers 62 By contrast the Atlantic sea scallop Placopecten magellanicus is at historically high levels of abundance after recovery from overfishing 63 As food Edit Scallops with wine sauce Wikimedia Commons has media related to Scallop dishes Scallops are characterized by offering two flavors and textures in one shell the meat called scallop which is firm and white and the roe called coral which is soft and often brightly coloured reddish orange Sometimes markets sell scallops already prepared in the shell with only the meat remaining Outside the U S the scallop is often sold whole They are available both with and without coral in the UK and Australia 64 Scallops without any additives are called dry packed while scallops that are treated with sodium tripolyphosphate STPP are called wet packed STPP causes the scallops to absorb moisture prior to the freezing process thereby increasing their weight The freezing process takes about two days 65 better source needed In Galician cuisine scallops are baked with breadcrumbs ham and onions citation needed In Japanese cuisine scallops may be served in soup or prepared as sashimi or sushi citation needed In a sushi bar hotategai 帆立貝 海扇 is the traditional scallop on rice and while kaibashira 貝柱 may be calscallop is more loosely used to include other shellfish species with round shaped flesh the adductor muscle such as Atrina 帶子 Dried scallop is known in Cantonese Chinese cuisine as conpoy 乾瑤柱 乾貝 干貝 citation needed Smoked scallops are sometimes served as appetizers or used as an ingredient in the preparation of various dishes and appetizers 66 Scallops have lent their name to the culinary term scalloped which originally referred to seafood creamed and served hot in the shell 67 Today it means a creamed casserole dish such as scalloped potatoes which contains no seafood at all citation needed Adductor muscle meat of the giant scallop seven white circular items with a large shrimp Dried scallops also known as conpoy Taiwanese steamed scallops A scallop being grilled next to sausages in Japan Fried scallops on a stick served with rice Pan seared scallopsSymbolism of the shell Edit Saint James by Carlo Crivelli c 1480 Shell of Saint James Edit See also Camino de Santiago Scallop symbol Shield with symbol of St James the Great Church of the Good Shepherd Rosemont Pennsylvania The scallop shell is the traditional emblem of St James the Great and is popular with pilgrims returning from the Way of St James Camino de Santiago and the apostle s shrine at Santiago de Compostela in Galicia Spain 68 Medieval Christians would collect a scallop shell while at Compostela as evidence of having made the journey The association of Saint James with the scallop can most likely be traced to the legend that the apostle once rescued a knight covered in scallops 69 An alternative version of the legend holds that while St James remains were being transported to Galicia Spain from Jerusalem the disciples witnessed a bridegroom on horseback fall into the water and emerge covered in the shells 70 Indeed in French the mollusc itself as well as a popular preparation of it in cream sauce is called coquille St Jacques In German they are Jakobsmuscheln literally James s shellfish Curiously the Linnaean name Pecten jacobeus is given to the Mediterranean scallop while the scallop endemic to Galicia is called Pecten maximus due to its bigger size 71 The scallop shell is represented in the decoration of churches named after St James such as in St James Church Sydney where it appears in a number of places including in the mosaics on the floor of the chancel 72 When referring to St James a scallop shell valve is displayed with its convex outer surface showing In contrast when the shell refers to the goddess Venus see below it is displayed with its concave interior surface showing 71 Shell of Saint Augustine Edit Saint Augustine is said to have been walking along the seashore meditating on the unfathomable mystery of the Holy Trinity A boy was using a shell to pour seawater into a little hole When Augustine asked what he was doing he replied I am emptying the sea into this hole Thus did Augustine understand that man would never penetrate to the depths of the mystery of God 73 This symbolic meaning was taken up by Joseph Ratzinger in his coat of arms as Archbishop of Munich and also retained by him when elected Pope Benedict XVI While a doctoral candidate in 1953 Ratzinger wrote his dissertation on The People of God and the House of God in Augustine s Teaching and the shell therefore has a personal connection with the thought of Saint Augustine 73 Badge Edit A scallop shell in a German coat of arms The scallop shell symbol found its way into heraldry as a badge of those who had been on the pilgrimage to Compostela although later it became a symbol of pilgrimage in general Winston Churchill and Diana Princess of Wales family the Spencer family coat of arms includes a scallop as well as both of Diana s sons Prince William Duke of Cambridge and Prince Harry s personal coats of arms also Pope Benedict XVI s personal coat of arms includes a scallop another example is the surname Wilmot and also John Wesley s which as a result the scallop shell is used as an emblem of Methodism However charges in heraldry do not always have an unvarying symbolic meaning and there are cases of arms in which no family member went on a pilgrimage and the occurrence of the scallop is simply a pun on the name of the armiger as in the case of Jacques Coeur or for other reasons 74 In 1988 the State of New York in the US chose the bay scallop Argopecten irradians as its state shell 75 Fertility symbol Edit Aphrodite Anadyomene from Amisos 1st century BC 1st century AD Throughout antiquity scallops and other hinged shells have symbolized the feminine principle 76 Outwardly the shell can symbolize the protective and nurturing principle and inwardly the life force slumbering within the Earth 77 an emblem of the vulva 78 79 Many paintings of Venus the Roman goddess of love and fertility included a scallop shell in the painting to identify her This is evident in Botticelli s classically inspired 15th century painting The Birth of Venus 80 One legend of the Way of St James holds that the route was seen as a fertility pilgrimage undertaken when a young couple desired to bear offspring The scallop shell is believed to have originally been carried by pagans as a symbol of fertility 81 82 Other interpretations Edit Alternatively the scallop resembles the setting sun which was the focus of the pre Christian Celtic rituals of the area citation needed To wit the pre Christian roots of the Way of St James was a Celtic death journey westwards towards the setting sun terminating at the End of the World Finisterra on the Coast of Death Costa da Morte and the Sea of Darkness i e the Abyss of Death the Mare Tenebrosum Latin for the Atlantic Ocean itself named after the Dying Civilization of Atlantis 83 better source needed Contemporary art Edit Large sculpture by Maggi Hambling titled The Scallop erected in 2003 on the beach at Aldeburgh England The beach at Aldeburgh Suffolk England features Maggi Hambling s steel sculpture The Scallop erected in 2003 as a memorial to the composer Benjamin Britten who had a long association with the town 84 See also Edit Animals portalExplanatory notes Edit Also occasionally written scollop and once spelled scalap opp scalop skalop scalepp oppe scalloppe skallap op scallope scallap s c kollop and scollup op as well as escallop escalop and escollop though scallop appears to have become the dominant way of spelling the word in English 1 Raines B K amp Poppe G T 2006 The Family Pectinidae 38 Citations Edit Whitney D W 1890 Scallop The Century Dictionary An Encyclopedic Lexicon of the English Language p 5371 Century Company and 2009 The Oxford English Dictionary Second Edition Oxford University Robinson amp Robinson 2000 p 65 Shumway amp Parsons 2011 p 207 Shumway amp Parsons 2011 p 124 Milsom amp Rigby 2009 p 62 a b c d e f g h Drew 1906 pp 5 6 Shumway amp Parsons 2011 p 59 a b c Hautmann Michael 2010 The first scallop PDF Palaontologische Zeitschrift 84 2 317 322 doi 10 1007 s12542 009 0041 5 S2CID 84457522 Harris Olivia K Kingston Alexandra C N Wolfe Caitlin S Ghoshroy Soumitra Johnsen Sonke Speiser Daniel I 2019 Core shell nanospheres behind the blue eyes of the bay scallop Argopecten irradians Journal of the Royal Society Interface 16 159 doi 10 1098 rsif 2019 0383 PMC 6833330 PMID 31640501 Speiser Daniel I Johnsen Sonke 29 December 2008 Comparative Morphology of the Concave Mirror Eyes of Scallops Pectinoidea American Malacological Bulletin 26 1 2 27 33 doi 10 4003 006 026 0204 S2CID 11584708 Speiser Daniel I Loew Ellis R Johnsen Sonke 1 February 2011 Spectral sensitivity of the concave mirror eyes of scallops potential influences of habitat self screening and longitudinal chromatic aberration Journal of Experimental Biology 214 3 422 431 doi 10 1242 jeb 048108 PMID 21228201 Eyes detect changing movement patterns queen scallop asknature org Land M F Fernald R D March 1992 The Evolution of Eyes Annual Review of Neuroscience 15 1 1 29 doi 10 1146 annurev ne 15 030192 000245 PMID 1575438 Speiser Daniel I Johnsen Sonke 1 July 2008 Scallops visually respond to the size and speed of virtual particles Journal of Experimental Biology 211 13 2066 2070 doi 10 1242 jeb 017038 PMID 18552295 Sun Xiujun Liu Zhihong Wu Biao Zhou Liqing Wang Qi Wu Wei Yang Aiguo 2018 Differences between fast and slow muscles in scallops revealed through proteomics and transcriptomics BMC Genomics 19 1 377 doi 10 1186 s12864 018 4770 2 PMC 5963113 PMID 29783952 Material was copied from this source which is available under a Creative Commons Attribution 4 0 International License a b Shumway amp Parsons 2011 pp 689 690 Dore 2013 p 152 Gosling 2015 p 29 Cheng J Y Davison I G Demont M E 1996 Dynamics and energetics of scallop locomotion Journal of Experimental Biology 199 9 1931 1946 doi 10 1242 jeb 199 9 1931 PMID 9319845 Joll L M 1989 Swimming behavior of the saucer scallop Amusium balloti Mollusca Pectinidae Marine Biology 102 3 299 305 doi 10 1007 BF00428481 S2CID 84250961 Land M F 1966 Activity in the optic nerve of Pecten maximus in response to changes in light intensity and to pattern and movements in optical environment PDF Journal of Experimental Biology 45 1 83 99 doi 10 1242 jeb 45 1 83 PMID 5969013 a b Philipp E E R Schmidt M Gsottbauer C Sanger A M Abele D 2008 Size and age dependent changes in adductor muscle swimming physiology of the scallop Aequipecten opercularis Journal of Experimental Biology 211 15 2492 2501 doi 10 1242 jeb 015966 PMID 18626084 Guerra C Zenteno Savin T Maeda Martinez A N Abele D Philipp E E R 2013 The effect of predator exposure and reproduction on oxidative stress parameters in the Catarina scallop Argopecten ventricosus Comparative Biochemistry and Physiology A 165 1 89 96 doi 10 1016 j cbpa 2013 02 006 PMID 23416890 Boadas M A Nusetti O Mundarain F 1997 Seasonal variation in the properties of muscle mitochondria from the tropical scallop Euvola Pecten ziczac Marine Biology 128 2 247 255 doi 10 1007 s002270050089 S2CID 84538863 Matlins 2001 p 56 a b Bloom S 1975 The motile escape response of a sessile prey a sponge scallop mutualism Journal of Experimental Biology and Ecology 17 3 311 321 doi 10 1016 0022 0981 75 90006 4 a b Pitcher C R Butler A J 1987 Predation by asteroids escape response and morphometrics of scallops with epizoic sponges Journal of Experimental Marine Biology and Ecology 112 3 233 249 doi 10 1016 0022 0981 87 90071 2 a b Forester A J 1979 The association between the sponge Halichondria panicea Pallas and scallop Chlamys varia L a commensal protective mutualism Journal of Experimental Marine Biology and Ecology 36 1 1 10 doi 10 1016 0022 0981 79 90096 0 Donovan D Bingham B Farren H Gallardo R Vigilant V 2002 Effects of sponge encrustation on the swimming behaviour energetics and morphometry of the scallop Chlamys hastata PDF Journal of the Marine Biological Association of the United Kingdom 82 3 469 476 doi 10 1017 s0025315402005738 S2CID 56338849 a b c Hart D R Chute A S 2004 Essential Fish Habitat Source Document Sea Scallop Placopecten magellanicus Life History and Habitat Characteristics PDF NOAA Tech Memo NMFS NE 189 Scallop Aquaculture PDF College of Marine Science University of South Florida Rice 2012 p 47 Waller T R 1993 The evolution of Chlamys Mollusca Bivalvia Pectinidae in the tropical western Atlantic and eastern Pacific American Malacological Bulletin 10 2 195 249 Harper et al 2000 p 254 Malkowsky Yaron Klussmann Kolb Annette May 2012 Phylogeny and spatio temporal distribution of European Pectinidae Mollusca Bivalvia Systematics and Biodiversity 10 2 233 242 doi 10 1080 14772000 2012 676572 S2CID 84085349 Waller Thomas R 2006 Shumway Sandra E ed New phylogenies of the Pectinidae Mollusca Bivalvia Reconciling morphological and molecular approaches Scallops biology ecology and aquaculture II Amsterdam Elsevier pp 1 44 Brand A R 2006 Scallop ecology distributions and behavior Scallops Biology Ecology and Aquaculture Developments in Aquaculture and Fisheries Science Vol 35 pp 651 744 doi 10 1016 S0167 9309 06 80039 6 ISBN 9780444504821 Raines Poppe amp Groh 2006 Barucca M Olmo E Schiaparelli S amp Canapa A 2004 Molecular phylogeny of the family Pectinidae Mollusca Bivalvia Waller Thomas R 1972 The functional significance of some shell micro structures in the Pectinacea Paleontology International Geological Congress pp 48 56 Shumway Sandra E Parsons G Jay eds 7 June 2016 Scallops Biology Ecology Aquaculture and Fisheries Elsevier Science p 5 ISBN 978 0 444 62719 3 Waller Thomas R 1986 A new genus and species of scallop Bivalvia Pectinidae from off Somalia and the definition of a new tribe Decatopectinin i Nautilus 100 2 39 46 doi 10 5962 bhl part 26491 Shumway amp Waller 1991 pp 1 73 sfn error no target CITEREFShumwayWaller1991 help Waller Thomas R 1993 The evolution of Chlamys Mollusca Bivalvia Pectinidae in the tropical western Atlantic and eastern Pacific American Malacological Bulletin 10 2 195 249 Alejandrino A Puslednik L Serb J M 2011 Convergent and parallel evolution in life habit of the scallops BMC Evolutionary Biology 11 1 164 doi 10 1186 1471 2148 11 164 PMC 3129317 PMID 21672233 Waller Thomas R 2007 The evolutionary and biogeographic origins of the endemic Pectinidae Mollusca Bivalvia of the Galapagos Islands Journal of Paleontology 81 5 929 950 doi 10 1666 pleo05 145 1 S2CID 86121432 Dijkstra H H Maestrati P 2012 Pectinoidea Mollusca Bivalvia Propeamussiidae Cyclochlamydidae n fam Entoliidae and Pectinidae from the Vanuatu Archipelago Zoosystema 34 2 389 408 doi 10 5252 z2012n2a12 S2CID 85935928 Waller Thomas R 1984 The ctenolium of scallop shells functional morphology and evolution of a key family level character in the Pectinacea Mollusca Bivalvia Malacologia 25 1 203 219 Puslednik L Serb J M 2008 Molecular phylogenetics of the Pectinidae Mollusca Bivalvia and the effect of outgroup selection and increased taxon sampling on tree topology Molecular Phylogenetics and Evolution 48 3 1178 1188 doi 10 1016 j ympev 2008 05 006 PMID 18579415 Barucca M Olmo E Schiaparelli S Capana A 2004 Molecular phylogeny of the family Pectinidae Mollusca Bivalvia based on mitochondrial 16S and 12S rRNA genes Molecular Phylogenetics and Evolution 31 1 89 95 doi 10 1016 j ympev 2003 07 003 PMID 15019610 a b c Matsumoto M Hayami I 2000 Phylogenetic analysis of the family Pectinidae Bivalvia based on mitochondrial cytochrome C oxidase subunit Journal of Molluscan Studies 66 4 477 488 doi 10 1093 mollus 66 4 477 Saavedra C Pena J B 2006 Phylogenetics of American scallops Bivalvia Pectinidae based on partial 16S and 12S ribosomal RNA gene sequences Marine Biology 150 1 111 119 doi 10 1007 s00227 006 0335 z S2CID 84205954 Pamilo P Nei M 1988 Relationships between gene trees and species trees Molecular Biology and Evolution 5 5 568 583 doi 10 1093 oxfordjournals molbev a040517 PMID 3193878 Wu C I 1991 Inferences of species phylogeny in relation to segregation of ancient polymorphisms Genetics 127 2 429 435 doi 10 1093 genetics 127 2 429 PMC 1204370 PMID 2004713 Waller Thomas R 1998 Origin of the Molluscan Class Bivalvia and a Phylogeny of Major Groups Pp 1 45 In P A Johnston amp J W Haggart eds Bivalves An Eon of Evolution Calgary University of Calgary Press xiv 461 pp Habe 1977 Shumway amp Parsons 2011 p 902 Walker Margaret 1991 What price Tasmanian scallops A report of morbidity and mortality associated with the scallop diving season in Tasmania 1990 South Pacific Underwater Medicine Society Journal 21 1 Archived from the original on 2013 10 20 Retrieved 2013 07 16 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint unfit URL link Orkney part of scallop discos fishing trial BBC News BBC 2022 06 06 Retrieved 2022 06 07 a b Arnold Naomi July August 2018 What we do in the shallows New Zealand Geographic 152 56 73 Scallops Forest and Bird Pinet 2011 p 333 Granata Flick amp Martin 2012 p 96 Shumway amp Parsons 2011 p 1355 Rolnick amp Peterson 2014 p 47 Broder Andy June 7 2012 AndyTalk Beyond Lox Smoked Seafood Hold the Bagels Phoenix New Times Archived from the original on June 9 2012 Retrieved January 31 2017 Rombauer amp Becker 1964 p 369 Thomas Hope B Werness line drawings by Joanne H Benedict and Hope B Werness additional drawings by Tiffany Ramsay Lozano and Scott 2003 The continuum encyclopedia of animal symbolism in art New York Continuum p 359 ISBN 9780826415257 Pullan Wendy 2013 Tracking the Habitual Observations on the Pilgrim s Shell Architecture and Pilgrimage 1000 1500 Ashgate Publishing Company p 67 ISBN 9781472410832 Starkie 1965 pp 70 71 a b Davies Paul Howard Deborah Pullan Wendy eds 2013 Architecture and pilgrimage 1000 1500 southern Europe and beyond Aldershot Hamps Ashgate Publishing pp 73 86 ISBN 9781472410832 The Church 1963 p 22 sfn error no target CITEREFThe Church1963 help a b Willard amp Owens 1997 p 68 Stix Stix amp Abbott 1968 p pages needed New York State Shell Bay Scallop State Symbols USA Retrieved 2012 05 24 Salisbury 2001 p 11 Fontana 1994 pp 88 103 Gutzwiller K 1992 The Nautilus the Halycon and Selenaia Callimachus s Epigram 5 Pf 14 G P Classical Antiquity 11 2 194 209 doi 10 2307 25010972 JSTOR 25010972 Johnson 1994 p 230 Birth of Venus artble com 2017 Retrieved 25 February 2017 Slavin S 2003 Walking as Spiritual Practice The Pilgrimage to Santiago de Compostela Body and Society 9 1 18 doi 10 1177 1357034X030093001 S2CID 144403461 Gauding 2009 p 169 Thomas Isabella Pilgrim s Progress Europe in the UK European Commission Archived from the original on March 23 2008 Retrieved January 21 2017 Dunford amp Lee 2012 p 486 General bibliography EditDore Ian 29 June 2013 The New Fresh Seafood Buyer s Guide A manual for distributors restaurants and retailers Boston MA Springer Science amp Business Media p 152 ISBN 978 1 4757 5990 7 Drew Gilman Arthur 1906 The Habits Anatomy and Embryology of the Giant Scallop Pecten Tenuicostatus Mighels Orono Maine pp 5 6 Dunford Martin Lee Phil 13 September 2012 The Rough Guide to Norfolk amp Suffolk Rough Guides p 486 ISBN 978 1 4053 9037 8 Fontana David 1994 The secret language of symbols a visual key to symbols and their meanings San Francisco Chronicle Books pp 88 103 ISBN 978 0 8118 0462 2 Gauding Madonna 2009 The Signs and Symbols Bible The Definitive Guide to Mysterious Markings Sterling Publishing Company p 169 ISBN 978 1 4027 7004 3 Gosling Elizabeth 27 April 2015 Marine Bivalve Molluscs John Wiley amp Sons p 29 ISBN 978 1 119 04522 9 Granata Linda Ankenman Flick George J Jr Martin Roy E 8 February 2012 The Seafood Industry Species Products Processing and Safety John Wiley amp Sons p 96 ISBN 978 1 118 22953 8 Habe Tadashige 1977 Bivalvia and Scaphopoda Systematics of mollusca in Japan Bivalvia and Scaphopoda Hokuryukan Harper Elizabeth Taylor John David Crame J Alistair Geological Society of London 2000 The Evolutionary Biology of the Bivalvia Geological Society of London ISBN 978 1 86239 076 8 Johnson Buffie 1994 Lady of the beasts the Goddess and her sacred animals Rochester Vt Inner Traditions Bear amp Company p 230 ISBN 978 0 89281 523 4 Matlins Antoinette L 2001 The Pearl Book The Definitive Buying Guide how to Select Buy Care for amp Enjoy Pearls New York NY Gemstone p 56 ISBN 978 0 943763 35 4 Milsom Clare Rigby Sue 1 April 2009 Fossils at a Glance Chichester John Wiley amp Sons p 62 ISBN 978 1 4443 1123 5 Pinet Paul R 28 December 2011 Invitation to Oceanography Jones amp Bartlett Publishers p 333 ISBN 978 1 4496 0192 8 Rice Tony 3 December 2012 Can Squid Fly Can squid fly answers to a host of fascinating questions about the sea and sea life London Thomas Reed publications Bloomsbury Publishing p 47 ISBN 978 1 4081 5130 3 Rolnick Glenn Peterson Chris November 4 2014 Carmine s celebrates classic Italian recipes for everyday feasts New York St Martin s Press p 47 ISBN 978 1 4668 3723 2 Raines Bret K Poppe Guido T Groh Klaus 2006 A conchological iconography Hackenheim Germany ConchBooks p 402 ISBN 978 3 925919 78 7 Robinson Chuck Robinson Debbie 2000 The Art of Shelling A Complete Guide to Finding Shells and Other Beach Collectibles at Shelling Locations from Florida to Maine Old Squan Village Publishing p 65 ISBN 978 0 9647267 8 9 Rombauer Irma S Becker Marion Rombauer 1964 1931 The Joy of Cooking Indianapolis Indiana Bobbs Merrill p 369 ISBN 978 0 452 25665 1 Salisbury Joyce E 2001 Encyclopedia of women in the ancient world Santa Barbara Calif ABC CLIO p 11 ISBN 978 1 57607 092 5 Shumway Sandra E Parsons G Jay eds 22 September 2011 Scallops Biology Ecology and Aquaculture 2nd ed Amsterdam Boston Elsevier pp 689 690 ISBN 978 0 08 048077 0 Starkie Walter 1965 1959 The Road to Santiago Berkeley Los Angeles University of California Press p 71 Retrieved 20 January 2017 Stix Hugh Stix Marguerite Abbott Robert Tucker 1968 The Shell Five Hundred Million Years of Inspired Design First ed New York NY Harry N Abrams Inc ISBN 978 0810904750 Willard Barbara Owens Mary B 1 September 1997 Augustine Came to Kent Warsaw N D San Francisco Bethlehem Books Ignatius Press ISBN 978 1 883937 21 8 External links Edit Look up scallop in Wiktionary the free dictionary Wikispecies has information related to Pectinidae Wikibooks Cookbook has a recipe module on Scallop Mollusca Bivalvia Pectinidae at Natural History Museum Rotterdam photos of Pectinidae shells Retrieved from https en wikipedia org w index php title Scallop amp oldid 1136403968, wikipedia, wiki, book, books, library,

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