Pinctada fucata [Status Unaccepted]   (Gould,  1850) (Oyster)
Organism information awaits expert curation
Class: Bivalvia

Image copyrights: FAO

Color: The outer surface of the shell valves is reddish or yellowish-brown with radiating rays of lighter color. The nacreous layer is thick and has a bright golden-yellow metallic lustre.

The hinge is fairly long and its ratio to the broadest width of the shell is about 0.85 and that to the dorsoventral measurement is about 0.76. The left valve is deeper than the right. Hinge teeth are present in both valves, one each at the anterior and posterior ends of the ligament. The anterior ear is larger than in the other species, and the byssal notch, at the junction of the body of the shell and the ear, is slit-like. The posterior ear is fairly well developed. The adductor scar is elongated and sub-central. The pallial line and scars are caused by the insertion of the pallial muscles in fan-shaped bundles of fibers radiating outwards. There are 12–15 insertion scars between the umbo and antero-ventral border. Besides these distinct scars, there is a narrow continuous insertion band confluent with the posterior and ventral edges of the adductor scars. Its scar merges with that of the adductor scar. Body consists of a viscero-pedal mass covered by the
right and left mantle lobes which are free anteriorly, ventraUy and posteriorly
but fused dorsally. The mantle edge has two thin, folds with pigmented,
papillate edges. The outer fold is parallel to the inner surface of the xhdl .and
the inner fold called the pallial veil or velum projects at right angles from the mantle edges. In life the pallial veils of the opposite sides are in contact with
each other except in the regions of the inhalent aperture about mid-ventrally and the exhalent aperture at the posterior end. The foot is elongated and muscular arising about mid-way between the mouth and the intestinal lobe and has a groove ventrally. The byssus is at the proximal end of the foot and bears byssus fibres with which the pearl oyster attaches itself to the substratum. The adductor muscle consists of a narrow region formed of white, glistening muscle fibres and a broad region of colourless semi-translucent fibres. The alimentary canal consists of the mouth provided with two pairs of labial palps, the oesophagus, the stomach and a coiled intestine. The digestive gland surrounds the stomach and in healthy oysters a crystalline style is present in the intestine. The rectum passes through the pericardium, curves ventrally and lies around the opsterior aspect of the adductor muscle terminating in the anus.

Mantle-The free edge of the mantle lobe is thick, pigmented and fringed with branched tentacles. The pallial edge of the mantle is attached to the shell, a little away from the margin. Each pallial lobe may be divided into three parts, the central, distal or muscular and marginal mantle.
Foot- The foot is highly mobile, tongue-shaped organ capable of considerable elongation and contraction. The major part of the foot is composed of a network of fibers running in various directions, thus ensuring a wide range of movement.
Byssal gland- The byssus gland organ is located ventrally at the proximal end of the foot. Each fiber of the byssus anchors the pearl oyster to rocks and other hard objects by means of a discoid attachment at the distal extremity.
Muscular system- The pearl oyster is monomyarian, possessing only the posterior adductor, the largest and the most important muscle in its body. The adductor muscle stretches transversely across the body from valve to valve. It is a massive wedge-shaped bundle of muscle fibers.
Digestive system- The oesophagus, stomach, and the greater portion of the intestine lie within the viscero-pedal mass. Two horizontal lips, the labial palps, conceal the aperture of the mouth. The mouth is a large, slit-like depression placed transversely between the anterior levator muscles of the foot.
Respiratory system-The gills consist of four crescent-shaped plates, two halfgills on each side which hang down from the roof of the mantle cavity like book leaves. They represent a series of ciliated sieves, providing an efficient feeding surface. Two rows of long delicate branchial filaments are inserted at right angles along the whole length of the axis or vascular base which extends from the ventral border of the palps anteriorly curving round ventrally and posteriorly to a point opposite the anus. Its convexity extends first forwards and then downwards. Where they terminate, the mantle lobes of the two sides are slightly united by the inner mantle folds thus dividing the mantle cavity into a large inhalant chamber containing the gills and a much smaller exhalant chamber. Water enters by one and leaves by the other.
Circulatory system- This system consists of a heart and a series of arteries which lie above the adductor, and contained in a pericardium. The heart consists of a single ventricle and a pair of contractile thin walled auricles, one on each side. They receive blood from the body by way of the gills and mantle, and pass it to the ventricle. Back-flow of blood is prevented by valves. The blood of the pearl oyster is colorless.
Excretory system- The excretory system consists of a pair of nephridia and numerous small pericardial glands projecting from the walls of the auricles. The nephridia are two large symmetrical pouch-like sacs located on either side in the hinder half of the viscero-pedal mass. Each nephridium opens into the pericardium by a wide duct and to the exterior by a minute pore.
Nervous system- The nervous system is laterally symmetrical and has three pairs of ganglia, (1) the cerebral ganglia at the sides of the oesophagus, (2) the pedals joined to form a single ganglion at the base of the foot and (3) a pair of large visceral or parieto-splanchnic ganglia lying upon the anterior surface of the adductor. The stout paired cerebro-visceral connectives link the cerebral ganglia with the parieto-splanchnic ganglia, while a pair of cerebro pedal connectives join the cerebral ganglia with the pedal nerve mass.
Reproductive system- The sexes are separate except in occasional cases. The gonads are paired but asymmetrical.

The sexes are separate although hermaphrodite conditions have been observed in some individuals. Change of sex takes place in some oyster towards the end of spawning. A slight rise in water temperature may be considered as the stimulating factor for the onset of the gametogenic cycle and a slight reduction in water temperature stimulates the oysters to spawn.

Synonym (s)
Avicula fucata Gould, 1850
Pinctada fucata Virabhadra Rao and Satyanarayana Rao, 1974
Perlamater vulgaris Schumacher, 1817
Pteria (Margaritifera) vulgaris Jameson, 1901
Margaritifera vulgaris Homell, 1922
Pteria vulgaris Gravely, 1941

Common Name (s)
• Muthu Chippi (Tamil)
• Pearl Oyster (English)
Economic Importance and Threats
Importance:  Commercial
(Production of pearls; edible)
Cultured:  Yes

Habitat:  Reef Associated, Rocky
Trophic Level:  Consumer
Prey:  Unicellular organisms (infusorians, foraminifers and radiolarians), minute embryos and larvae of various organisms, algal filaments, spicules of alcyonarians and sponges, diatoms, flagellates, larvae of lamellibranchs, gastropods, heteropods, crustacean nauplii, appendages and frustules of copepods, spicules of sponges and unidentified spores, algal filaments, detritus and sand particles
Predator:  Gastropods (Cymatium cingulatum and Murex virgeneus), benthic fish which feed on young oysters below one year of age, rays, octopods and starfish which feed on adult oysters; Some invertebrate animals and fishes


• Lakshadweep INDIA
• Gujarat, Pirotan Island INDIA
• Palk Bay INDIA
• Tamil Nadu, Tuticorin INDIA
• Tamil Nadu, Krusadai Island INDIA
• Andhra Pradesh, Vishakhapatnam INDIA
• Andaman and Nicobar Islands INDIA
• Red Sea
• Persian Gulf
• Karnataka, Netrani Island (Lat: 14.01) (Long: 74.33) INDIA (Record: 08/05/2006) (Depth: -12 mts)
• Tamil Nadu, Gulf of Mannar INDIA
• Gujarat, Gulf of Kachchh INDIA
• Kerala, Vizhinjam INDIA
• kerala INDIA
• Tamil Nadu, Dhanushkodi INDIA
• Andhra Pradesh, Visakhapatnam INDIA
• Tamil Nadu, Porto Novo (Lat: 11.48) (Long: 79.77) INDIA
• Gujarat, Saurashtra INDIA

Literature Source(s)
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Surya Rao, KV and Subba Rao, NV (1991) Mollusca State fauna series 2: Fauna of Lakshadweep ZSI, Calcutta 273-362 Available at - NIO, Goa
  • (1991) Pearl oyster farming and pearl culture Available at -
  • Zacharia, PU; Krishnakumar, PK; Dineshbabu, AP; Vijayakumaran, K; Rohit, P; Thomas, S; Sasikumar, G; Kaladharan, P; Durgekar, RN and Mohamed, KS (2008) Species assemblage in the coral reef ecosystem of Netrani Island off Karnataka along the southwest coast of India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin, India 50(1) 87-97 Available at - NIO, Goa
  • Rao, DVS; Rao, KS; Iyer, CSP and Chittibabu, P (2008) Possible ecological consequences from the Sethu Samudram Canal Project, India Marine Pollution Bulletin Elsevier 56(2) 170-186 Available at -
  • Mohamed, KS; Kripa, V; Jugnu, R; Radhakrishnan, P; Alloycious, PS; Sharma, J; Joseph, M and Velayudhan, TS (2007) Mortality of farmed pearl oyster Pinctada fucata (Gould, 1850) due to the blooming of Noctiluca scintillans and Cochlodinium sp. at Kollam Bay, Kerala journal of marine biological association of india Cochin, India 49(2) 213-218 Available at -
  • Alagarswami, K and Narasimham, KA (1973) Clam, cockle and oyster resources of the indian coasts Living resources of the seas around India CMFRI, Cochin 648-658 Available at -
  • Samuel, VD; Chacko, D and Edward, JKP (2005) Preliminary study on the molluscan diversity of “the lost world’’– Dhanushkodi, east coast of India Proceedings of the National Seminar on Reef Ecosystem Remediation SDMRI Special Research Publication No.9 54-58 Available at -
  • Rao, KV and Rao, KS (1974) Pearl Oysters The commercial molluscs of India Bulletin Of Central Marine Fisheries Research Institute CMFRI, Cochin 25 84-105 Available at -
  • Jones, S (1969) The molluscan fishery resources of India Proceedings of the Symposium on Mollusca CMFRI 906-918 Available at -
  • Dholakia, AD (2004) Marine resources Fisheries and aquatic resources of India Daya publishing house 271-303 Available at - NIO, Goa
  • Pati, SK; Rao, MV; Balaji, M and Pachu, AV (2011) Community Structure of fouling on a sunken vessel from Visakhapatnam harbour, east coast of India Journal of the Marine Biological Association of India The Marine Biological Association of India 53(1) 14-20 Available at - NIO,Goa
  • Pillai, PKM and Augustine, SK (2000) A code list of common marine living resources of the Indian seas CMFRI Special Publication No.12 CMFRI 1-115 Available at -
  • Jayabal, R and Kalyani, M (1989) Check list of estuarine and marine bivalves of Porto Novo waters Mahasagar NIO, Goa 22(3) 147-150 Available at - NIO,Goa

Page last updated on:2012-01-25

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