Lingulata
Encyclopedia
Lingulata is a class of brachiopod
, among the oldest of all brachiopods having existed since the Cambrian
period (550 mya). They are also among the most morphologically conservative of the brachiopods, having lasted from their earliest appearance to the present with very little change in shape. Shells of living specimens found today in the waters around Japan
are almost identical to ancient Cambrian fossil
s.
The Lingulata have tongue-shaped shells (hence the name Lingulata, from the Latin
word for "tongue") with a long fleshy stalk, or pedicle
, with which the animal burrows into sandy or muddy sediments. They inhabit vertical burrows in these soft sediments with the anterior end facing up and slightly exposed at the sediment surface. The cilia of the lophophore
generate a feeding and respiratory current through the lophophore and mantle cavity. The gut is complete and J-shaped.
Lingulata shells are composed of a combination of calcium phosphate
, protein
and chitin
. This is unlike most other shelled marine animals, whose shells are made of calcium carbonate
. The Lingulata are inarticulate brachiopods, so named for the simplicity of their hinge mechanism. This mechanism lacks teeth and is held together only by a complex musculature. Both valves are roughly symmetrical.
The genus Lingula
(Bruguiere, 1797) is the oldest known animal genus that still containins extant species. It is primarily an Indo
-Pacific genus that is harvested for human consumption in Japan and Australia
.
Brachiopod
Brachiopods are a phylum of marine animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection...
, among the oldest of all brachiopods having existed since the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
period (550 mya). They are also among the most morphologically conservative of the brachiopods, having lasted from their earliest appearance to the present with very little change in shape. Shells of living specimens found today in the waters around 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...
are almost identical to ancient Cambrian fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s.
The Lingulata have tongue-shaped shells (hence the name Lingulata, 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 for "tongue") with a long fleshy stalk, or pedicle
Pedicle (zoology)
In zoology, the pedicle refers to a fleshy line brachiopods and some bivalve mollusks use to attach and anchor to a substrate. In brachiopods, the pedicle emerges from a pedicle opening. Some brachiopods do not have a functional pedicle, and thus do not have this pedicle opening....
, with which the animal burrows into sandy or muddy sediments. They inhabit vertical burrows in these soft sediments with the anterior end facing up and slightly exposed at the sediment surface. The cilia of the lophophore
Lophophore
The lophophore is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Entoprocta, and Phoronida. All lophophores are found in aquatic organisms.-Characteristics:...
generate a feeding and respiratory current through the lophophore and mantle cavity. The gut is complete and J-shaped.
Lingulata shells are composed of a combination of calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....
, protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
and chitin
Chitin
Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...
. This is unlike most other shelled marine animals, whose shells are made of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
. The Lingulata are inarticulate brachiopods, so named for the simplicity of their hinge mechanism. This mechanism lacks teeth and is held together only by a complex musculature. Both valves are roughly symmetrical.
The genus Lingula
Lingula (genus)
Lingula is a genus of brachiopods within the class Lingulata. Lingula is known since the Tertiary.-Species:The following species are recognised:*Lingula adamsi Dall, 1873*Lingula anatina Lamarck, 1801*Lingula dregeri Andreae, 1893...
(Bruguiere, 1797) is the oldest known animal genus that still containins extant species. It is primarily an Indo
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
-Pacific genus that is harvested for human consumption in Japan and 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...
.