Strombus canarium
Encyclopedia
Laevistrombus canarium, commonly known
as the dog conch and still better known under its synonym Strombus canarium, is a species
of edible sea snail
, a marine
gastropod mollusk in the family
Strombidae
, the true conch
s. An Indo-Pacific
species, L. canarium lives on mud and sandy bottoms, grazing on algae
and detritus
. The shell of adult individuals is colored light yellowish-brown to golden to gray. It has a characteristic inflated body whorl
, a flared and thick outer lip
, and a shallow stromboid notch
. Although it is considered to have value as an ornament, because the shell is heavy and compact it is often used as sinker for fishing nets.
The external anatomy of the soft parts of this species is similar to that of other strombid
snails; the animal has an elongate snout
, thin eyestalk
s with well-developed eyes and sensory tentacles, and a narrow, strong foot with a sickle-shaped operculum
attached. Among the predators of this snail are carnivorous gastropods such as cone snail
s and volutes
, as well as humans, who consume the soft parts in a wide variety of dishes.
The dog conch is an economically
important species in the Indo-West Pacific
, and several studies indicate that it may be currently suffering population
declines due to overfishing
and overexploitation
. Malacologists and ecologists have recommended the reduction of the current exploitation rates; recent initiatives in Thailand
are attempting to ensure the reproduction of younger individuals, as well as managing the natural populations in general.
The first published depictions of the shell of Laevistrombus canarium appeared in 1684, in the earliest book that was solely about sea shells, Recreatio mentis et oculi in observatione animalium testaceorum (translation: Refreshment of the mind and the eye in the observation of shell-bearing animals) by the Italian scholar Filippo Buonanni. The species was shown in the 1742 Index Testarum Conchyliorum, quae adservantur in Museo Nicolai Gualtieri (translation: List of the shells of shellfish which are preserved in the museum of Niccolò Gualtieri) by the Italian physician
and malacologist Niccolò Gualtieri
. In both books the morphology
of an adult dog conch shell was shown from different perspectives.
In 1758, the dog conch was formally described
by the Swedish naturalist
and taxonomist Carl Linnaeus. The specific name canarium is derived from the Latin
word canis
and its root can, meaning dog
. The original description
given by Linnaeus in the book Systema Naturae
is written in Latin, and reads as follows:
"S. testae labro rotundato brevi retuso, spiraque laevi." This can be translated as Strombus (S.) with a shell (testae) having a retuse (retuso), short (brevi), rounded (rotundato) lip
(labro), and (-que) a smooth (laevi) spire
(spira). Linnaeus did not mention a specific locality in his original description, giving only Eastern Asia as the area in which the species is found.
The synonym
s that are listed in the taxobox are other binomial names that were given over time to this taxon
by authors who were not aware that the specimens they were describing belonged to a species that Linnaeus had already described; in some cases they may have been misled into thinking they had a different species because of local variations in color and form. Strombus vanicorensis is a subsequent changed spelling of Strombus vanikorensis by one of the original authors of that species.
In the Malay Peninsula
, this species is known by the Malay
common names siput gonggong and gong-gong; "siput" means snail and "gonggong" means a dog's bark or howl. L. canarium comprises at least two known subspecies
, one of them being Laevistrombus canarium canarium (Linnaeus, 1758), and the other one is Laevistrombus canarium guidoi (Man in 't Veld & De Turck, 1998).
, the stromboid notch
on the outer lip is quite inconspicuous. When a normal adult dextral shell of this species is viewed ventrally, and with the anterior end pointing downwards, the stromboid notch can be observed to the right of the siphonal canal
as a shallow secondary anterior indentation in the lip. The siphonal canal itself is straight, short and ample, and the columella
is smooth without any folds
.
Adult specimens have a moderately flared outer lip, which is considerably thickened and completely devoid of marginal spikes or plicae. The body whorl
is roundly swollen at the shoulder, with a few anterior spiral grooves. The shell has a medium to high conoidal spire
, with at least five delicately furrowed whorl
s.
The shell color varies a great deal from golden yellow to light yellowish brown to gray. The underside of the shell is rarely dark, more frequently it is paler or totally white, but in all cases the shell aperture
is white. Mature specimens sometimes present a metallic gray or golden brown gloss on the margin of the outer lip and the callus. A zig-zag network of darker brown lines is sometimes present on the outside of the shell, but this is considered to be uncommon.
The periostracum
, a layer of protein (conchiolin
) which is the outermost part of the shell surface, is yellowish-brown in color, and is usually thick and reticulated (net-like), and is fimbriated (fringed) over the suture. The corneous
operculum
is dark brown in color. Its shape is fairly typical of the family Strombidae—a slightly bent sickle
, with seven to eight weak lateral serrations.
individuals of Laevistrombus canarium are generally larger (both shell and soft parts) than male
individuals, as is the case in other strombid
gastropods, among them the spider conch Lambis chiragra
and the queen conch Eustrombus gigas. The external anatomy of the soft parts of this species is very similar to that of the other members of the family: the animal has a long extensible snout and thin eyestalk
s (also known as ommatophores) having at the tips well developed lens eye
s. Each eyestalk has, branching off near the end, a small sensory tentacle. The large foot of the animal is narrow and strong, and is able to perform the leaping form of locomotion
which also occurs in other species of Strombidae
such as the queen conch E. gigas.
(a tree of descent
) that attempts to show the phylogenetic relationships of 34 species within the family Strombidae. The authors analysed 31 species in the genus Strombus
including Strombus canarium, and three species in the allied genus Lambis
. The cladogram was based on DNA
sequences of both nuclear histone H3
and mitochondrial cytochrome-c oxidase I
(COI) protein-coding gene
regions. In this proposed phylogeny, Strombus canarium, Strombus vittatus
and Strombus epidromis
are closely related and appear to share a common ancestor.
and Sri-Lanka to Melanesia
, southern Japan
and northern Australia
. Regions and countries where this species has been recorded include:
Tanjung Adang Shoal, Merambong
Shoal, Tanjung Bin, Tanjung Surat and Pasir Gogok in the Johor Straits
; Records also include Pulau Tinggi
, Pulau Besar
and Pulau Sibu
, Port Dickson
and Teluk Kemang in eastern Johor and Negeri Sembilan
, as well as Pulau Pangkor, Pulau Langkawi
, Cape Rachado, Kilat, and western Johor Straits. The dog conch has also been recorded in Thailand
, Indonesia
and Vietnam
.
. This curious series of maneuvers was first described by the American zoologist George Howard Parker
(1864–1955) in 1922. The animal first fixes the posterior end of the foot by having the point of the sickle-shaped operculum thrust into the substrate
. Then it extends its foot forward, further lifting the shell and throwing it ahead in a so-called leaping motion.
Burrowing behavior, in which an individual sinks itself entirely or partially into the substrate, is frequent among strombid gastropods. The burrowing behavior of S. canarium consists of a series of movements which are characteristic of the species. There are three consecutive phases: first the probing phase, in which the animal thrusts the anterior portion of the foot into the substrate to gain hold; then the shoveling phase, in which it pushes the substrate using the long extensible proboscis, and then finally the retracting phase, in which it moves the shell along an anterior-posterior axis in order to settle the substrate around it. Usually some of the dorsal portion of the shell is still visible, even though the ventral surface and the animal's soft parts are buried.
The escape response
in gastropods, which consists of the perception of stimuli (for example, the presence of a predator nearby) and a subsequent escape motion, is a frequent target of behavioral studies. In gastropods, the perception of environmental chemical stimuli originating, for example, from food or other organisms, is possibly mediated by sensory organs such as the osphradium
. In the case of S. canarium, the perception of a predator can occur either chemically or by vision, which is well-developed in strombid
gastropods. The presence of a predator can significantly alter the movement pattern of S. canarium, inducing an increase in the frequency of leaps.
and seagrass
beds of insular
and continental shores, and usually prefers major islands and continental coasts rather than the shores of small islands, though this may not be an absolute rule. It can be found in both the littoral
and sublittoral zones, from shallow waters to 55 m (180&n bsp;ft) depths. S. canarium is normally found in large colonies
, and is usually abundant wherever it occurs.
Strombid gastropods were commonly accepted as carnivore
s during the 19th century. This erroneous conception was based on the writings of the French naturalist
Jean Baptiste Lamarck, who classified strombids alongside other supposedly carnivorous snails. However, subsequent studies have refuted the concept completely, and proved that strombid gastropods are herbivorous animals. Nowadays, as is the case in other Strombidae
, Laevistrombus canarium is known to be a herbivore, feeding on algae
, and occasionally on detritus
.
Many carnivorous marine gastropod snails are known predators of S. canarium, including the volutes
Cymbiola nobilis
and Melo melo
, and the cone snail Conus textile
.
, which means that each individual animal is either distinctly male or female. The breeding season starts in late November and continues until early March. After internal fertilization
, the female of S. canarium produces and spawns
a long gelatinous tubular structure containing multiple egg
s. This structure then coils itself and compacts to form a creamy-white colored egg mass. Each one of those egg masses may contain about 50–70 thousand eggs, and the females usually lay them on seagrass
, where they remain attached. In approximately 110–130 hours, the embryo
of L. canarium grows from a single cell
to a veliger
, a larval form common to various marine and fresh-water gastropod and bivalve mollusks, and then hatches
. The hatching process requires 12–15 hours to occur. After hatching, L. canarium larvae
can be assigned to four distinct developmental stages throughout their short planktonic life, based on morphological features and other prominent characters. Usually, larvae that are 0–3 days old are Stage I veligers; 4–8 day old larvae are Stage II; 9–16 day old larvae are Stage III, and 17 day old until metamorphosis
are Stage IV. L. canarium larvae show a faster development when compared to other species in the same family, among which are the West Indian fighting conch Strombus pugilis
, and the milk conch Lobatus costatus. However, larval development may be highly influenced by environmental conditions, such as temperature and the quality and availability of food. The metamorphosis
in L. canarium can be recognized by the loss of the larval velar lobes, and by the typical leaping motion of juvenile
conch
s.
Studies from 2008 indicate that sexual dimorphism
occurs very early during this species' ontogeny
. L. canarium males reach their sexual maturity
at a lower shell length compared to females. Individuals are usually considered to be adult
by the time the outer lip
of their shell is noticeably thickened and flared; growing to adult size usually takes about a year. The maximum life span
of the dog conch differs between sexes, and is estimated at 2 and 2.5 years for females and males respectively.
s, cutlets, noodles, curry
, and chilli
. Despite their considerable ornamental value, L. canarium shells are also traditionally used by local fishermen as sinkers for their fishing net
s. Studies indicate that L. canarium has been overexploited and overfished recently in many areas, and malacologists and ecologists have recommended the reduction of exploitation rates in order to maintain its availability as a natural resource. For instance, dog conchs are now considered rare in Singapore
, probably as a result of unsustainable exploitation. Finding large dog conch individuals has become an increasingly difficult task in several regions where this species occurs. Recent initiatives conducted in Phuket
(Thailand
) intend to increase the depleted natural stocks of L. canarium by reintroducing cultured animals in local seagrass beds. Fishermen are being encouraged not to collect younger, smaller individuals, so that their future reproduction may be assured.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
as the dog conch and still better known under its synonym Strombus canarium, is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of edible sea snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Strombidae
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
, the true conch
Conch
A conch is a common name which is applied to a number of different species of medium-sized to large sea snails or their shells, generally those which are large and have a high spire and a siphonal canal....
s. An Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
species, L. canarium lives on mud and sandy bottoms, grazing on algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
. The shell of adult individuals is colored light yellowish-brown to golden to gray. It has a characteristic inflated body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
, a flared and thick outer lip
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
, and a shallow stromboid notch
Stromboid notch
The stromboid notch is an anatomical feature which is found in the shell of one taxonomic family of medium sized to large sea snails, the conches....
. Although it is considered to have value as an ornament, because the shell is heavy and compact it is often used as sinker for fishing nets.
The external anatomy of the soft parts of this species is similar to that of other strombid
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
snails; the animal has an elongate snout
Snout
The snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
, thin eyestalk
Eyestalk
In anatomy, an eyestalk is a protrusion that extends the eye away from the body, giving the eye a better field of view than if it were unextended. It is common in nature and in fiction....
s with well-developed eyes and sensory tentacles, and a narrow, strong foot with a sickle-shaped operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
attached. Among the predators of this snail are carnivorous gastropods such as cone snail
Cone snail
Conidae is a taxonomic family of minute to quite large sea snails, marine gastropod molluscs in the superfamily Conoidea.The snails within this family are sophisticated predatory animals...
s and volutes
Voluta
Voluta is a genus of medium to large sea snails, marine gastropod molluscs in the family Volutidae, the volutes. -Species:Species in the genus Voluta include:* Voluta ebraea Linnaeus, 1758* Voluta morrisoni...
, as well as humans, who consume the soft parts in a wide variety of dishes.
The dog conch is an economically
Economy
An economy consists of the economic system of a country or other area; the labor, capital and land resources; and the manufacturing, trade, distribution, and consumption of goods and services of that area...
important species in the Indo-West Pacific
Indo-West Pacific
The Indo-West Pacific, or IWP, is a zoogeographical region spanning the entire Indian Ocean including the Red Sea and the Pacific Ocean as far as the Caroline Islands but short of the Marshall Islands...
, and several studies indicate that it may be currently suffering population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
declines due to overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
and overexploitation
Overexploitation
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Sustained overexploitation can lead to the destruction of the resource...
. Malacologists and ecologists have recommended the reduction of the current exploitation rates; recent initiatives in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
are attempting to ensure the reproduction of younger individuals, as well as managing the natural populations in general.
Taxonomy and naming
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...
and malacologist Niccolò Gualtieri
Niccolò Gualtieri
Niccolò Gualtieri was an Italian doctor and malacologist. In 1742, he published Index Testarum Conchyliorum, quae adservantur in Museo Nicolai Gualtieri . Gualtieri was a professor at the University of Pisa...
. In both books the morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
of an adult dog conch shell was shown from different perspectives.
In 1758, the dog conch was formally described
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
by the Swedish naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
and taxonomist Carl Linnaeus. The specific name canarium is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
word canis
Canis
Canis is a genus containing 7 to 10 extant species, including dogs, wolves, coyotes, and jackals, and many extinct species.-Wolves, dogs and dingos:Wolves, dogs and dingos are subspecies of Canis lupus...
and its root can, meaning dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
. The original description
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
given by Linnaeus in the book Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
is written in Latin, and reads as follows:
"S. testae labro rotundato brevi retuso, spiraque laevi." This can be translated as Strombus (S.) with a shell (testae) having a retuse (retuso), short (brevi), rounded (rotundato) lip
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
(labro), and (-que) a smooth (laevi) spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
(spira). Linnaeus did not mention a specific locality in his original description, giving only Eastern Asia as the area in which the species is found.
The synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
s that are listed in the taxobox are other binomial names that were given over time to this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
by authors who were not aware that the specimens they were describing belonged to a species that Linnaeus had already described; in some cases they may have been misled into thinking they had a different species because of local variations in color and form. Strombus vanicorensis is a subsequent changed spelling of Strombus vanikorensis by one of the original authors of that species.
In the Malay Peninsula
Malay Peninsula
The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...
, this species is known by the Malay
Malay language
Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...
common names siput gonggong and gong-gong; "siput" means snail and "gonggong" means a dog's bark or howl. L. canarium comprises at least two known subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, one of them being Laevistrombus canarium canarium (Linnaeus, 1758), and the other one is Laevistrombus canarium guidoi (Man in 't Veld & De Turck, 1998).
Shell description
Laevistrombus canarium has a heavy shell with a rounded outline. The maximum shell length of this species is up to 100 mm (3.9 in), but more commonly it grows to about 65 mm (2.6 in). The outer surface of the shell is almost completely smooth, and unlike species in the genus StrombusStrombus
Strombus, common name the true conchs, is a genus of medium to large sea snails with an operculum, marine gastropod mollusks in the family Strombidae, the true conchs and their immediate relatives....
, the stromboid notch
Stromboid notch
The stromboid notch is an anatomical feature which is found in the shell of one taxonomic family of medium sized to large sea snails, the conches....
on the outer lip is quite inconspicuous. When a normal adult dextral shell of this species is viewed ventrally, and with the anterior end pointing downwards, the stromboid notch can be observed to the right of the siphonal canal
Siphonal canal
Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure...
as a shallow secondary anterior indentation in the lip. The siphonal canal itself is straight, short and ample, and the columella
Columella
Lucius Junius Moderatus Columella is the most important writer on agriculture of the Roman empire. Little is known of his life. He was probably born in Gades , possibly of Roman parents. After a career in the army , he took up farming...
is smooth without any folds
Plait (gastropod)
A plait is an anatomical feature which is present the shells of some snails, or gastropods. This sculpture occurs often in the shells of marine gastropod mollusks in the clade Neogastropoda, but it is also found in some pulmonate land snails....
.
Adult specimens have a moderately flared outer lip, which is considerably thickened and completely devoid of marginal spikes or plicae. The body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
is roundly swollen at the shoulder, with a few anterior spiral grooves. The shell has a medium to high conoidal spire
Spire
A spire is a tapering conical or pyramidal structure on the top of a building, particularly a church tower. Etymologically, the word is derived from the Old English word spir, meaning a sprout, shoot, or stalk of grass....
, with at least five delicately furrowed whorl
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
s.
The shell color varies a great deal from golden yellow to light yellowish brown to gray. The underside of the shell is rarely dark, more frequently it is paler or totally white, but in all cases the shell aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...
is white. Mature specimens sometimes present a metallic gray or golden brown gloss on the margin of the outer lip and the callus. A zig-zag network of darker brown lines is sometimes present on the outside of the shell, but this is considered to be uncommon.
The periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
, a layer of protein (conchiolin
Conchiolin
Conchiolin and perlucin are complex proteins which are secreted by a mollusc's outer epithelium ....
) which is the outermost part of the shell surface, is yellowish-brown in color, and is usually thick and reticulated (net-like), and is fimbriated (fringed) over the suture. The corneous
Corneous
Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals....
operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
is dark brown in color. Its shape is fairly typical of the family Strombidae—a slightly bent sickle
Sickle
A sickle is a hand-held agricultural tool with a variously curved blade typically used for harvesting grain crops or cutting succulent forage chiefly for feeding livestock . Sickles have also been used as weapons, either in their original form or in various derivations.The diversity of sickles that...
, with seven to eight weak lateral serrations.
Soft parts
FemaleFemale
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
individuals of Laevistrombus canarium are generally larger (both shell and soft parts) than male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
individuals, as is the case in other strombid
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
gastropods, among them the spider conch Lambis chiragra
Lambis chiragra
Harpago chiragra, common name the Chiragra spider conch, is a species of very large sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs. - Shell description :...
and the queen conch Eustrombus gigas. The external anatomy of the soft parts of this species is very similar to that of the other members of the family: the animal has a long extensible snout and thin eyestalk
Eyestalk
In anatomy, an eyestalk is a protrusion that extends the eye away from the body, giving the eye a better field of view than if it were unextended. It is common in nature and in fiction....
s (also known as ommatophores) having at the tips well developed lens eye
Mollusc eye
The molluscs have the widest variety of eye morphologies of any phylum, and a large degree of variation in their function. Cephalopods' eyes are as complex as those of vertebrates; scallops have up to 100 simple eyes; and some bivalves have compound eyes....
s. Each eyestalk has, branching off near the end, a small sensory tentacle. The large foot of the animal is narrow and strong, and is able to perform the leaping form of locomotion
Animal locomotion
Animal locomotion, which is the act of self-propulsion by an animal, has many manifestations, including running, swimming, jumping and flying. Animals move for a variety of reasons, such as to find food, a mate, or a suitable microhabitat, and to escape predators...
which also occurs in other species of Strombidae
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
such as the queen conch E. gigas.
Phylogeny
In 2006, Latiolais and colleagues proposed a cladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
(a tree of descent
Tree of life (science)
Charles Darwin proposed that phylogeny, the evolutionary relatedness among species through time, was expressible as a metaphor he termed the Tree of Life...
) that attempts to show the phylogenetic relationships of 34 species within the family Strombidae. The authors analysed 31 species in the genus Strombus
Strombus
Strombus, common name the true conchs, is a genus of medium to large sea snails with an operculum, marine gastropod mollusks in the family Strombidae, the true conchs and their immediate relatives....
including Strombus canarium, and three species in the allied genus Lambis
Lambis
Lambis is a genus of large sea snails sometimes known as spider conchs, marine gastropod mollusks in the family Strombidae, the true conch family...
. The cladogram was based on DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
sequences of both nuclear histone H3
Histone H3
Histone H3 is one of the five main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a string' structure...
and mitochondrial cytochrome-c oxidase I
Main subunit of cytochrome c oxidase
Cytochrome C and Quinol oxidase polypeptide I is main subunit of cytochrome c oxidase complex.Cytochrome c oxidase is a key enzyme in aerobic metabolism. Proton pumping heme-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes...
(COI) protein-coding gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
regions. In this proposed phylogeny, Strombus canarium, Strombus vittatus
Strombus vittatus
Doxander vittatus, common name : the Vitate Conch, is a species of medium-sized sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs...
and Strombus epidromis
Strombus epidromis
Labiostrombus epidromis is a species of sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs....
are closely related and appear to share a common ancestor.
Distribution
Laevistrombus canarium is native to the coastal waters of the Indo-Pacific region. It occurs in the Indo-Pacific from IndiaIndia
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and Sri-Lanka to Melanesia
Melanesia
Melanesia is a subregion of Oceania extending from the western end of the Pacific Ocean to the Arafura Sea, and eastward to Fiji. The region comprises most of the islands immediately north and northeast of Australia...
, southern Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and northern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Regions and countries where this species has been recorded include:
Tanjung Adang Shoal, Merambong
Pulau Merambong
Pulau Merambong is an uninhabited island located in Johor, Malaysia, just off the western side of the Malaysia-Singapore Border. The island is dominated by mangrove swamp.-Conservation:...
Shoal, Tanjung Bin, Tanjung Surat and Pasir Gogok in the Johor Straits
Johor
Johor is a Malaysian state, located in the southern portion of Peninsular Malaysia. It is one of the most developed states in Malaysia. The state capital city and royal city of Johor is Johor Bahru, formerly known as Tanjung Puteri...
; Records also include Pulau Tinggi
Pulau Tinggi
Pulau Tinggi, otherwise known as Tinggi Island is a large sparsely inhabited island, which rises 2000 ft above sea level off the east coast of Johor, Malaysia. It was nicknamed the "General's Hat Island" by Chinese seamen hundreds of years ago...
, Pulau Besar
Pulau Besar (Johor)
Besar Island is an island off the east coast of Johor, Malaysia. It is accessible by boat from Mersing town...
and Pulau Sibu
Pulau Sibu
Pulau Sibu, also known as Sibu Island, is a small island off Malaysia's eastern coast, facing the South China Sea. It is actually made up of several islands namely Sibu Besar Island, Sibu Tengah Island, Sibu Kukus Island and Sibu Hujung Island....
, Port Dickson
Port Dickson
Port Dickson or PD to locals is a beach and holiday destination situated about 32 km from Seremban and 90 km from Kuala Lumpur. It is located in the state of Negeri Sembilan in Peninsular Malaysia...
and Teluk Kemang in eastern Johor and Negeri Sembilan
Negeri Sembilan
Negeri Sembilan, one of the 13 states that constitutes Malaysia, lies on the western coast of Peninsular Malaysia, just south of Kuala Lumpur and borders Selangor on the north, Pahang in the east, and Malacca and Johor to the south....
, as well as Pulau Pangkor, Pulau Langkawi
Langkawi
Langkawi, officially known as Langkawi, the Jewel of Kedah is an archipelago of 104 islands in the Andaman Sea, some 30 km off the mainland coast of northwestern Malaysia. The islands are a part of the state of Kedah, which is adjacent to the Thai border...
, Cape Rachado, Kilat, and western Johor Straits. The dog conch has also been recorded in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
and Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
.
Behavior
Compared to other gastropods, Laevistrombus canarium has a rather unusual means of locomotion, which is common only among the StrombidaeStrombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
. This curious series of maneuvers was first described by the American zoologist George Howard Parker
George Howard Parker
George Howard Parker was an American zoologist. He was Professor of Zoology at Harvard University and Fellow of the American Academy of Arts and Sciences...
(1864–1955) in 1922. The animal first fixes the posterior end of the foot by having the point of the sickle-shaped operculum thrust into the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. Then it extends its foot forward, further lifting the shell and throwing it ahead in a so-called leaping motion.
Burrowing behavior, in which an individual sinks itself entirely or partially into the substrate, is frequent among strombid gastropods. The burrowing behavior of S. canarium consists of a series of movements which are characteristic of the species. There are three consecutive phases: first the probing phase, in which the animal thrusts the anterior portion of the foot into the substrate to gain hold; then the shoveling phase, in which it pushes the substrate using the long extensible proboscis, and then finally the retracting phase, in which it moves the shell along an anterior-posterior axis in order to settle the substrate around it. Usually some of the dorsal portion of the shell is still visible, even though the ventral surface and the animal's soft parts are buried.
The escape response
Escape response
Escape response, escape reaction, or escape behaviour is a possible reaction in response to stimuli indicative of danger, in particular, it initiates an escape motion of an animal...
in gastropods, which consists of the perception of stimuli (for example, the presence of a predator nearby) and a subsequent escape motion, is a frequent target of behavioral studies. In gastropods, the perception of environmental chemical stimuli originating, for example, from food or other organisms, is possibly mediated by sensory organs such as the osphradium
Osphradium
The osphradium is the olfactory organ in certain molluscs, linked with the respiration organ.The main function of this is to test incoming water for silt and other possible food particles.It is used by all members of the Genus Conus....
. In the case of S. canarium, the perception of a predator can occur either chemically or by vision, which is well-developed in strombid
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
gastropods. The presence of a predator can significantly alter the movement pattern of S. canarium, inducing an increase in the frequency of leaps.
Ecology
The dog conch lives on muddy sand bottoms among algaeAlgae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
beds of insular
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
and continental shores, and usually prefers major islands and continental coasts rather than the shores of small islands, though this may not be an absolute rule. It can be found in both the littoral
Littoral
The littoral zone is that part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to...
and sublittoral zones, from shallow waters to 55 m (180&n bsp;ft) depths. S. canarium is normally found in large colonies
Colony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
, and is usually abundant wherever it occurs.
Strombid gastropods were commonly accepted as carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s during the 19th century. This erroneous conception was based on the writings of the French naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
Jean Baptiste Lamarck, who classified strombids alongside other supposedly carnivorous snails. However, subsequent studies have refuted the concept completely, and proved that strombid gastropods are herbivorous animals. Nowadays, as is the case in other Strombidae
Strombidae
Strombidae, commonly known as the true conchs, is a taxonomic family of medium-sized to very large sea snails, marine gastropod mollusks in the superfamily Stromboidea....
, Laevistrombus canarium is known to be a herbivore, feeding on algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, and occasionally on detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
.
Volutidae
Volutidae, common name volutes, are a taxonomic family of predatory sea snails that range in size from 9 mm to over 500 mm, marine gastropod mollusks...
Cymbiola nobilis
Cymbiola nobilis
Cymbiola nobilis is a species of sea snail, a marine gastropod mollusk in the family Volutidae, the volutes....
and Melo melo
Melo melo
Melo melo, common name the Indian volute or bailer shell, is a very large sea snail, a marine gastropod mollusc in the family Volutidae, the volutes.-Distribution:...
, and the cone snail Conus textile
Conus textile
Conus textile, common name the cloth of gold cone is a venomous species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails, cone shells or cones. The species is extremely dangerous to humans.-Distribution:C...
.
Life cycle
Laevistrombus canarium is gonochoristicGonochorism
In biology, gonochorism or unisexualism describes sexually reproducing species in which individuals have just one of at least two distinct sexes. The term is most often used with animals . The sex of an individual may change during its lifetime, this can for example be found in parrotfish...
, which means that each individual animal is either distinctly male or female. The breeding season starts in late November and continues until early March. After internal fertilization
Internal fertilization
In mammals, internal fertilization is done through copulation, which involves the insertion of the penis into the vagina. Some other higher vertebrate animals reproduce internally, but their fertilization is cloacal.The union of spermatozoa of the parent organism. At some point, the growing egg or...
, the female of S. canarium produces and spawns
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
a long gelatinous tubular structure containing multiple egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s. This structure then coils itself and compacts to form a creamy-white colored egg mass. Each one of those egg masses may contain about 50–70 thousand eggs, and the females usually lay them on seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
, where they remain attached. In approximately 110–130 hours, the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
of L. canarium grows from a single cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
to a veliger
Veliger
A veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...
, a larval form common to various marine and fresh-water gastropod and bivalve mollusks, and then hatches
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
. The hatching process requires 12–15 hours to occur. After hatching, L. canarium larvae
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...
can be assigned to four distinct developmental stages throughout their short planktonic life, based on morphological features and other prominent characters. Usually, larvae that are 0–3 days old are Stage I veligers; 4–8 day old larvae are Stage II; 9–16 day old larvae are Stage III, and 17 day old until metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
are Stage IV. L. canarium larvae show a faster development when compared to other species in the same family, among which are the West Indian fighting conch Strombus pugilis
Strombus pugilis
Strombus pugilis, common names the fighting conch, or the West Indian fighting conch, is a species of medium to large sea snail, a marine gastropod mollusk in the family Strombidae, the true conchs....
, and the milk conch Lobatus costatus. However, larval development may be highly influenced by environmental conditions, such as temperature and the quality and availability of food. The metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
in L. canarium can be recognized by the loss of the larval velar lobes, and by the typical leaping motion of juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
conch
Conch
A conch is a common name which is applied to a number of different species of medium-sized to large sea snails or their shells, generally those which are large and have a high spire and a siphonal canal....
s.
Studies from 2008 indicate that sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
occurs very early during this species' ontogeny
Ontogeny
Ontogeny is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan...
. L. canarium males reach their sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at a lower shell length compared to females. Individuals are usually considered to be adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....
by the time the outer lip
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
of their shell is noticeably thickened and flared; growing to adult size usually takes about a year. The maximum life span
Maximum life span
Maximum life span is a measure of the maximum amount of time one or more members of a population has been observed to survive between birth and death.Most living species have at least one upper limit on the number of times cells can divide...
of the dog conch differs between sexes, and is estimated at 2 and 2.5 years for females and males respectively.
Human uses and conservation measures
The flesh of the dog conch is edible. It constitutes an important food staple for locals living along the seashore, and is fished in many parts of South East Asia. The meat is used in a wide variety of common dishes, such as soupSoup
Soup is a generally warm food that is made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth.Traditionally,...
s, cutlets, noodles, curry
Curry
Curry is a generic description used throughout Western culture to describe a variety of dishes from Indian, Pakistani, Bangladeshi, Sri Lankan, Thai or other Southeast Asian cuisines...
, and chilli
Chili con carne
Chili con carne is a spicy stew. The name of the dish derives from the Spanish chile con carne, "chili pepper with meat". Traditional versions are made, minimally, from chili peppers, garlic, onions, and cumin, along with chopped or ground beef. Beans and tomatoes are frequently included...
. Despite their considerable ornamental value, L. canarium shells are also traditionally used by local fishermen as sinkers for their fishing net
Fishing net
A fishing net or fishnet is a net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and...
s. Studies indicate that L. canarium has been overexploited and overfished recently in many areas, and malacologists and ecologists have recommended the reduction of exploitation rates in order to maintain its availability as a natural resource. For instance, dog conchs are now considered rare in Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
, probably as a result of unsustainable exploitation. Finding large dog conch individuals has become an increasingly difficult task in several regions where this species occurs. Recent initiatives conducted in Phuket
Phuket Province
Phuket , formerly known as Thalang and, in Western sources, Junk Ceylon , is one of the southern provinces of Thailand...
(Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
) intend to increase the depleted natural stocks of L. canarium by reintroducing cultured animals in local seagrass beds. Fishermen are being encouraged not to collect younger, smaller individuals, so that their future reproduction may be assured.