| Tonicella marmorea | |
|---|---|
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Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Polyplacophora |
| Order: | Chitonida |
| Family: | Ischnochitonidae |
| Genus: | Tonicella |
| Species: | T. marmorea |
| Binomial name | |
| Tonicella marmorea (O. Fabricius, 1780) [1] | |
| Synonyms [1] | |
| |
Tonicella marmorea is a species of chiton, a polyplacophoran mollusc found in the Arctic Ocean and the North Atlantic Ocean. It was first described by the Danish missionary and naturalist Otto Fabricius. [2]
Tonicella marmorea is broadly oval and grows to a length of about 4 cm (1.6 in). The eight plates of which the shell is composed are smooth and glossy, reddish-brown, marbled or patterned with intricate pale brown or white zigzag lines. The girdle which surrounds the shell is wide, thin and leathery, and also reddish-brown. Round its margin are small, flattened spines in red, purple or green, sometimes with paler bands. There are 17 to 25 pairs of gills, usually in the posterior part of the mantle groove, but sometimes scattered along the groove. [3] On the ventral side is the yellowish muscular foot, with the mouth at the anterior end and the anus at the posterior end. [4] In the northwestern Atlantic the colouring may vary. [5]
This species occurs in the Arctic Ocean and the North Atlantic Ocean. Its range includes the eastern coast of North America, Greenland, Norway, Sweden, and Britain, where it is largely confined to Scotland, Northern Ireland and northern England. It is quite common in Scottish sea lochs, and it has been common in Strangford Lough, but is becoming less so. [6] It lives on rocks, and on and under pebbles at depths from the littoral zone down to about 200 m (660 ft). [3]
Tonicella marmorea has a strong muscular foot that enables it to grip the substrate firmly; the plates have individual bundles of muscle fibres and this allows it to conform to the irregularities of the rock surface. If it becomes detached from the substrate, it can roll itself defensively into a ball. It lacks eyes or sensory organs on the head, but instead has aesthetes on its plates and girdle; these are sensory organs and function as a dispersed, compound eye. Beneath the mantle, cilia on the gills create a water current for respiration, and this current also carries away waste products. In its feeding habits, the chiton resembles a gastropod, grazing on algae with its reinforced radula. However, it differs from a gastropod in having a long, coiled gut, and forming faecal pellets, which pass out with the water current. [5]
The sexes are separate in this species. The gametes pass out with the water current and are liberated into the sea. In many chiton species, the timing of liberation of gametes is synchronized with the phase of the moon and the tides. The larvae are planktonic and when sufficiently developed, settle on the seabed and undergo metamorphosis into juveniles without passing through an intervening veliger stage. [5]
Chitons are marine molluscs of varying size in the class Polyplacophora, formerly known as Amphineura. About 940 extant and 430 fossil species are recognized.
The tusk shells or tooth shells, technically the Scaphopoda, are members of a class of shelled marine mollusc with worldwide distribution, and are the only class of exclusively infaunal marine molluscs. Shells of species within this class range from about 0.5 to 15 cm in length. Members of the order Dentaliida tend to be significantly larger than those of the order Gadilida.
The gumboot chiton also known as the giant western fiery chiton, is the largest of the chitons, growing to 36 cm (14 in) and over 2 kg (4.4 lb). It is found along the shores of the northern Pacific Ocean from Central California to Alaska, across the Aleutian Islands to the Kamchatka Peninsula and south to Japan. It inhabits the lower intertidal and subtidal zones of rocky coastlines.
Acanthochitona zelandica is a species of chiton in the family Acanthochitonidae, also sometimes known as the hairy, or "tufted," chiton. It probably developed during the mid to late Pleistocene, and is endemic to New Zealand.
Tonicella lineata, commonly known as the lined chiton, is a species of chiton from the North Pacific.
Mopalia spectabilis, commonly known as the red-flecked mopalia, is a species of chiton.
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Splendrillia lucida is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.
Mopalia ciliata is a chiton in the genus Mopalia, commonly known as the hairy chiton. It is a medium-sized marine mollusc up to 5.0 cm in length. It is oval shaped with 8 separate moderately elevated, overlapping ridged valves on its dorsal surface. It resides along the coast of North America.
Katharina tunicata is commonly known as the black Katy chiton, black Leather chiton, black chiton, or leather chiton is a species of chiton in the family Mopaliidae.
Acanthochitona fascicularis is a common chiton in the family Acanthochitonidae.
Tryblidiida is a taxon of monoplacophoran molluscans containing the only extant representatives: 37 species are still alive today, inhabiting the ocean at depths of between 175 and 6,400 metres.
Lolliguncula brevis, or the Atlantic brief squid, is a small species of squid in the Loliginidae family. It is found in shallow parts of the western Atlantic Ocean.
Donax vittatus, or the banded wedge shell, is a species of bivalve mollusc in the order Cardiida. It is found on beaches in northwest Europe buried in the sand on the lower shore.
Onchidoris proxima is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusc in the family Onchidorididae. This species is found in the northeastern and northwestern parts of the Atlantic Ocean. It is also reported from the northeastern Pacific Ocean. Previously in the genus Adalaria this species was moved to Onchidoris as a result of a molecular phylogeny study.
Chiton olivaceus, the green chiton, is a species of chiton, a marine polyplacophoran mollusk in the family Chitonidae, the typical chitons.
Acanthochitona garnoti, the spiny chiton, is a medium-sized polyplacophoran mollusc in the family Acanthochitonidae, found on the coast of southern Africa.
Biuve fulvipunctata, the white-speckled headshield slug, is a species of sea slug or headshield slug, a marine opisthobranch gastropod mollusc in the family Aglajidae. This species is widespread in the Indian and Pacific Oceans but has invaded the Mediterranean Sea since 1961, despite apparently being absent from the Red Sea until recorded there in the 21st century. It is the only species in the monotypic genus Biuve.
Pontobdella muricata is a species of marine leech in the family Piscicolidae. It is a parasite of fishes and is native to the northeastern Atlantic Ocean, the Baltic Sea, the North Sea, and the Mediterranean Sea.
Acanthochitona crinita is a species of marine chiton in the family Acanthochitonidae. It is found on rocky coasts in the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea.
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