Tectus+Maculatus

**Maculated Top Shell ** toc

Scientific name: //Trochus maculatus// Linnaeus 1758 Common names: Maculated Top Shell, Spotted Top Shell Snail Etymology: The species epithet refers to the snail's maculated (spoted) shell Synonyms: (from SeaLifeBase)
 * [|Trochus maculatus] || Linnaeus, 1758 || accepted name ||
 * [|Trochus stellatus] || (non Gmelin, 1791) || misapplied name ||
 * [|Tectus maculatus] || Linnaeus, 1758 || <span style="font-family: Georgia,serif;">synonym ||
 * <span style="font-family: Georgia,serif;">[|Trochus verrucosus] || <span style="font-family: Georgia,serif;">Gmelin, 1791 || <span style="font-family: Georgia,serif;">synonym ||

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Biology ** = <span style="font-family: Georgia,serif;">


 * <span style="color: #a10ca1; font-family: Georgia,serif;">Habitat **

<span style="font-family: Georgia,serif;">General: Coral rubble, rocky habitat. <span style="font-family: Georgia,serif;">From low in the intertidal zone to a depth of about 10m.

<span style="font-family: Georgia,serif;">In Singapore: T. maculatus is found mostly in crevices in seawalls, stones and large boulders, usually alone. Shores where they have been found include East Coast, Labrador, Pulau Sekudu, St John's Island, Lazarus Island, Kusu Island, Sisters Island, Pulau Hantu and Pulau Semakau, Tanah Merah, Sentosa and Cyrene Reef.

<span style="font-family: Georgia,serif;">** Feeding ** <span style="font-family: Georgia,serif;"> This species is a non-selective grazer and is considered to be a nocturnal feeder. It feeds on macrophytes, blue-green algae and benthic diatoms. Things common in its diet include green alga (Enteromorpha sp.), red alga (Hidenbrandtia sp.), and benthic diatoms (Navicula sp. and Nitzchia sp.) //T. maculatus// is not a picky eater and will consume other food when its preferred food is unavailable (Thapanand et al, 1995). A study has found that moderate disturbance in terms of freshwater runoff and ecologically relevant amounts of the heavy metal copper can reduce grazing activity by //T. maculatus// without a corresponding decrease in macro-algae production (Elfwing and Tedengren, 2002). Grazing helps to maintain low macroalgal standing crops in the tropics, and such a reduction in herbivory can result in phase shifts, where large and fleshy macroalgae increases at the expense of hard coral cover (Done, 1992; Hughes 1994).

<span style="font-family: Georgia,serif;">** Reproduction ** <span style="font-family: Georgia,serif;"> Separate sexes, external fertilization. Eggs are laid singly in seawater and hatched as free-swimming planktonic larvae, or bound in gelatinous masses and then frequently hatching as crawling juvelines (Rome, 1998). Fertilized eggs metamorphose into the creeping stage within 7 days and can be observed by the naked eye within a month. //T. maculatus// can only spawn in the new moon period and may be induced to do so using thermal shock (Chunhabundit et al, 1994).

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Commercial Value & Significance ** =

<span style="color: #a10ca1; font-family: Georgia,serif;">**Food** <span style="font-family: Georgia,serif;">Collected for its edible flesh and nacreous shell in Japan and Philippines and other Southeast Asian countries.

<span style="font-family: Georgia,serif;">Shells are utilized by shellcraft industries, sometimes serving as mother-of-pearl or as lime material.
 * <span style="color: #a10ca1; font-family: Georgia,serif;">Craft/Decorative **




 * <span style="color: #a10ca1; font-family: Georgia,serif;">Stamps **

<span style="font-family: Georgia,serif;">//T. maculatus// is featured on a 1985 stamp from the Cocos Islands (Keeling Islands): <span style="font-family: Georgia,serif;"> <span style="font-family: Georgia,serif;">(image from stamp-gallery)

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Distribution ** =

<span style="font-family: Georgia,serif;">//T. maculatus// is widespread in the Indo-West Pacific, from East Africa to Melanesia; north to Japan. and south to Southern Queensland and New Caledonia. Here is a map showing the distribution (Rome,1998):



=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Taxonavigation ** = <span style="font-family: Georgia,serif; font-size: 13px;">This information is provided to allow you to search for more general information on the upper hierarchical taxa (groupings) that //T. maculatus// belongs to//.//

<span style="font-family: Georgia,serif; font-size: 13px;">Kingdom: Animalia <span style="font-family: Georgia,serif; font-size: 13px;">Phylum: Mollusca <span style="font-family: Georgia,serif; font-size: 13px;">Class: Gastropoda <span style="font-family: Georgia,serif; font-size: 13px;">Subclass: Vetigastropoda <span style="font-family: Georgia,serif; font-size: 13px;">Superfamily: Trochoidea <span style="font-family: Georgia,serif; font-size: 13px;">Family: Trochidae <span style="font-family: Georgia,serif; font-size: 13px;">Subfamily: Trochinae <span style="font-family: Georgia,serif; font-size: 13px;">Genus: Trochus

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Diagnosis ** =

<span style="font-family: Georgia,serif; font-size: 15px;">Want to know for sure that the snail you're staring at on a rocky shore is //T. maculatus//? Here are some simple pointers on how to distinguish //T. maculatus// from other similar Trochidae species. (images from Rome, 1998)

> <span style="font-family: Georgia,serif;"> > <span style="font-family: Georgia,serif;"> >
 * 1) <span style="font-family: Georgia,serif; font-size: 15px;">Umbilicus is present. Should not be confused with members of the genus //Tectus//, which have no umbilicus.
 * 1) <span style="font-family: Georgia,serif; font-size: 15px;">Columella is dentate. Should not be confused with //Trochus conus,// which has a smooth columella.
 * 1) <span style="font-family: Georgia,serif; font-size: 15px;">May be distinguished by the axial streaks on its shell and base with radiating streaks or spots. Should not be confused with //Trochus hanleyanus// which has fine axial lines on its shell and base with numerous, crowded and wavy radiating lines.

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Description ** =

<span style="font-family: Georgia,serif;">** Shell Structure ** <span style="font-family: Georgia,serif;">

> rounded. > and finely beaded spiral threads. > corded.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Shell medium sized (up to 7 cm long), thick and solid, highly variable, **conical** in shape, about as wide as long to markedly longer.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Spire tall, often strongly narrowed in its upper part and with pointed apex, whorls either concave, flat or convexly bulging, their sides covered with numerous spiral rows of irregularly sized **granules** (usually 6 to 8 per whorl).
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Granules either rounded and separated or laterally compressed, like axial folds, giving occasionally short axial ribs at the otherwise rather shallow sutures.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Periphery of body whorl acutely
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Base of shell **flat**, with many low
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">**Umbilicus** present, spirally
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Aperture roughly quadrate to <span style="font-family: Georgia,serif;">[[image:taxo4254/trochh.JPG align="right"]] subtrigonal.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Outer lip strongly oblique above periphery, delicately lirate inside.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Columella with 4 to 5 low spiral cords, giving its margin a **multi-****dentate** aspect.

<span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">(Rome, 1998)

<span style="color: #a10ca1; font-family: Georgia,serif;">** Colour **


 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Outside of shell extremely variable, usually whitish with roughly axial stripes or blotches of deep red, purple, or brown, with the stripes occupying more space than the ground colour or vice-versa.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Stripes radiating, often narrower, discontinuous and somewhat lighter coloured on the base.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Umbilicus area and columella nacreous.
 * <span style="color: #231f20; font-family: Georgia,serif; font-size: 13px;">Shell often covered in algae and other encrusting organisms.

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Phylogenetic Position ** =

<span style="color: black; font-family: Georgia,serif;">Here are the resulting phylogenetic trees from 2 studies that have included //T. maculatus//.

<span style="color: black; font-family: Georgia,serif;">A molecular phylogeny by Williams et al. (2010) for Trochidae and Calliostomatidae based on analysis of concatenated sequences from four genes (28S rRNA, 12S rRNA, 16S rRNA and COI) produced by Bayesian analysis incorporating an uncorrelated relaxed, lognormal clock using BEAST. All taxa for which sequence was available for both 28S rRNA and at least two mitochondrial genes were included. Tree is a maximum clade credibility tree with median node height based on 67,500 trees. Support values are posterior probabilities (PP) (only shown where PP > 50%). All trochid subfamilies were recovered as monophyletic groups as indicated by grey boxes and are labelled on the right in grey text. No scale bar is provided because the root was arbitrarily set to one, and all other branch lengths are relative. Species names used in trees are ‘traditional’ names and do not reflect changes to taxonomy suggested by this study. <span style="font-family: Georgia,serif;">

<span style="font-family: Georgia,serif;">Below is a Wagner tree illustrating the hypothetical phylogenetic relationships among 6 taxa from the genera Trochus and Tectus. Total tree distance was 2.419 (Borsa and Benzie, 1993).

<span style="font-family: Georgia,serif;">

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif;">** Genome Information ** = <span style="font-family: Georgia,serif;">Here are some links to databases providing sequences for phylogenetic studies and other uses: <span style="font-family: Georgia,serif;">Nucleotide (14) <span style="font-family: Georgia,serif;">Protein (5) <span style="font-family: Georgia,serif;">PopSet (7) <span style="font-family: Georgia,serif;">Taxonomy (1)

=<span style="background-color: #ffffff; color: #008080; font-family: Georgia,serif; font-size: 160%;">Comments =

<span style="font-family: Georgia,serif;">If you have any suggestions or comments, please feel free to start a discussion under the 'Discussion' tab at the top of this page. All comments will appear in this section. Alternatively, you may directly click on a post below to reply to it.

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=<span style="color: #008080; font-family: Georgia,serif;">** References ** =

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Borsa, P., Benzie, J.A.H. (1993) Genetic relationships among the topshells Trochus and Tectus (Prosobranchia, Trochidae) from the great-barrier reef. Journal of Molluscan Studies Vol 59, p275-284 doi: 10.1093/mollus/59.3.275

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Chunhabundit, S., Thapanand, T. (1994) Some culture techniques of topshell Trochus maculatus L. Thai Journal of Aquatic Science.

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Elfwing, T., Tedengren, M. (2002) Effects of copper and reduced salinity on grazing activity and macroalgae production: a short-term study on a mollusc grazer, Trochus maculatus and two species of macroalgae in the inner Gulf of Thailand. Marine Biology Vol 140 Issue 5 p913-919 doi: 10.1007/s00227-001-0763-8

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Done, T.J. (1992) Phase shifts in coral reef communities and their ecological significance. Hydrobiologia 247:121-132

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Hughes T. (1994) Catastrophes, phase shifts, and large-scale degradation of a Caribbean coral reef. Science 265:1547-1551

<span style="color: black; font-family: Georgia,serif; font-size: 12px;">Rome. (1998) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume1. Seaweeds, corals, bivalves and gastropods. Food and Agriculture Organization of the United Nations.

<span style="font-family: Georgia,serif;"> Thapanand, T., Chunhabundit, S. (1995) Some biological aspects of topshell Trochus maculatus L. around Khang Khao Island, Cholburi. Thai Journal of Aquatic Science

<span style="color: black; font-family: Georgia,serif; text-decoration: none;">Williams, S.T., Donald, K.M., Spencer, H.G., Nakano, T. (2010) Molecular systematics of the marine gastropod families Trochidae Calliostomatidae (Mollusca: Superfamily Trochoidea). Molecular PHylogenetics and Evolution, Vol 54, Issue 3, p783-809

<span style="font-family: Georgia,serif;">Wilson, B., 1993. Australian Marine Shells. Prosobranch Gastropods Pt I. Odyssey Publishing, Leederville, W.A