Thursday, 24 May 2012

Azores’s marine Invertebrate -2010

The Portuguese archipelago of the Azores, isolated in the middle of the Atlantic Ocean and more than 1300 km from the nearest continent, is formed by the nine immersed tops of an underwater mountain range. On July 01, 2010, Portugal Post (Azores) issued the stamp set  to  recall special attention to the necessary ecological alarm against mankind’s aggressions to the planet’s frail balance.

Portuguese stamps displaying regional themes from the Azores. This is the case with the stamps that over the years have been devoted to the flora and fauna of the Azores, and with this issue as well, which focuses on the archipelago’s marine invertebrates. In the large group formed by animals without backbone, marine species usually stand out to the layman because of their shapes and colors that never cease to amaze us.
Grapsus adscenionis

Grapsus adscenionis is found   in Ascension Island, Azores Exclusive Economic Zone , East Atlantic . Despite the low commercial interest as food for human consumption, this species is becoming popular in aquaculture. Therefore,general biology and specific reproduction related information of the species will support a sustainable use of this fishery resource to avoid overexploitation.

The color pattern of Grapsus adscensionis varies according to the habitat. Adults have bright-red chelas with yellow-orange legs, brownish-red or spotted brown carapace.This species is an omnivorous opportunistic feeder and, apart from algae, it preys on another available food (worms, mollusks, dead animals, food wastes and other crustaceans).

The issue  stamps seek to recreate this world of beauty and polychromy, bringing attention not only to the starfish, the berried anemone, the spiral tube worm and the hermit crab, but first and foremost, on the two philatelic blocks to the peculiar natural framing of the red rock crab and the purple sea urchin.
Sphaerechinus granularis

Sphaerechinus granularis is a large sea urchin, somewhat flattened dorsally and growing to fifteen centimetres in diameter. There are two distinct colour forms. The test is purple in both but one has purple spines and the other white. The spines are short and blunt, all the same length, and arranged neatly in rows.S. granularis is found in the Mediterranean Sea and the eastern Atlantic Ocean, from the Channel Islands south to Cape Verde and the Gulf of Guinea. It favours sheltered locations and lives on rocks covered with seaweed or gravelly substrates.
Dardanus Calidus

Dardanus calidus is a scavenger, feeding on decaying matter from the sea bed.It has been collected from depths greater than 100 metres , but is more typically found in shallower water. Dardanus calidus is a species of hermit crab. Dardanus calidus can grow to a length of 12 centimetres.It uses large gastropod shells, such as those of Tonna galea and Charonia species, which it often decorates with one or more sea anemones of the species Calliactis parasitica. The relationship with the anemone is truly symbiotic, since the anemone gains scraps of food from the hermit crab, while the crab benefits from the anemone's stinging tentacles deterring predators.
Alicia Mirabilis

Alicia mirabilis is a large sea anemone species in the genus Alicia which found in East Atlantic Ocean, Mediterranean Sea. During the day time it may be found in a contracted state, shield shaped, brown in colour and covered with tubercles, while during night time it grows up in a columnar body, ending with many tentacles, extremely long and thin. The body become whitish or slightly blue, translucent, with scattered brown tubercles. It may reach forty centimetres of length.

Alicia mirabilis lives on rocks and between the roots of the Posidonia oceanica meadows.With its long tentacles, very poisoning even for human beings, it prey small fishes and swimming invertebrates.
Ophidiaster ophidianus

Ophidiaster ophidianus is a sea star of a diameter of 20 cm but sometimes up to 40 cm. the central disc is small. It has five long arms, round in cross-section and of the same size nearly on its whole length slightly tappering at their end. The arms tighten at the junction with the central disc. On the arms, short respiratory papillae arranged in lines run from the central disc to the arm ends. The purple starfish has variable colour : purple, orange or red sometimes with darker purple patches. Ophidiaster ophidianus is found on rocks from 5 to 25 m deep in the Mediterranean Sea and the Atlantic Ocean from the Azores to the Canary Islands, Madeira and Guinea Gulf.
Sabella spallanzanii

The European fan worm (Sabella spallanzanii) is one of the largest species in the family Sabellidae. It is a filter-feeding tube worm which has the potential to alter native marine ecosystems and compete with native organisms for food and space. The species also has the potential to influence aquaculture operations, both as a nuisance fouler and as a competitor to cultured filter-feeding species such as oysters and mussels.

The European fan worm is native to Mediterranean and eastern Atlantic Coast European countries including Spain, Portugal, Italy, France, Turkey and South America. It is commonly found in its native region in shallow subtidal areas and shows a clear preference for sheltered nutrient rich waters.

The European fan worm is a large tube dwelling annelid worm with a crown of feeding tentacles formed in two layers. One layer of tentacles is distinctly spiralled. The feeding tentacles can vary in colour from a uniform dull white to brightly banded with stripes of orange, purple and white.

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