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''Gromia sphaerica'' is a large spherical testate amoeba, a single-celled organism classed among the protists and is the largest in the genus ''Gromia''. It was discovered in 2000, along the Oman margin of the Arabian sea, at depths from . Specimens range in size from in diameter. The test (organic shell) is usually spherical in shape and honeycombed with pores. There are filaments on the bottom of the organism, where it is in contact with the seafloor, and it is mostly filled with stercomata (waste pellets).〔(Centre National de la Recherche Scientifique, "A large testate protist, ''Gromia sphaerica sp. nov.'' (Order Filosea), from the bathyal Arabian Sea" )〕 In 2008, specimens were found off the coast of Little San Salvador in the Bahamas by researchers from the University of Texas. These ''Gromia'' were discovered to make mud trails as much as in length. It was previously thought that single-celled organisms were incapable of making these kinds of trails, and their cause was previously a source of speculation. The mud trails made by the Bahamian ''Gromia'' appear to match prehistoric mud trails from the Precambrian, including 1.8 billion year-old fossil trails in the Stirling formation in Australia.〔( University of Texas at Austin College of Natural Sciences, "Discovery of Giant Roaming Deep Sea Protist Provides New Perspective on Animal Evolution" )〕〔http://www.sciencedaily.com/releases/2008/12/081203190030.htm〕 File:Gromia in situ closeup.png|Close-up of Gromia in place. Note the particles of sand and muck stuck to the surface. File:Gromia-field wInset.jpg|Multiple individuals of Gromia sphaerica on the slope of Exuma Valley, together with a shrimp for scale. The shrimp is about 10 cm long and maintains a horizontal position. Inset: details of individual traces. File:Gromia microscope processed.jpg|This is a close-up of a cleaned Gromia. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gromia sphaerica」の詳細全文を読む スポンサード リンク
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