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Canadia (genus)
''Canadia'' (meaning ''of Canada'' or ''after Canada'') is a genus of extinct annelid worm present in Burgess Shale type Konservat-Lagerstätte. It is found in strata dating back to the Delamaran stage of the Middle Cambrian around 505 million years ago, during the time of the Cambrian explosion. It was about in length. Charles Doolittle Walcott named ''Canadia'' in 1911 after Canada, the country from which its remains have been found.
==Description==
The most notable feature of ''Canadia'' is the many notosetae (rigid setae extending from dorsal branches of notopodia) along the back of the animal that are characteristic of polychaete worms. It has been suggested that these notosetae may have been iridescent when the organism was alive due to evidence of diffraction gratings found on the surface of some fossils.〔Parker, A. R. 1998. Colour in Burgess Shale animals and the effects of light on evolution in the Cambrian. Proceedings of the Royal Society of London Series B 265:967-972.〕 Tentacles extended from the prostomium and may have served as sensory organs. The gut of ''Canadia'' was straight and had the ability to extend out of the body in the form of a proboscis, suggesting that the animal was carnivorous. This is further evidenced by the lack of sediments found in the gut that would be present in a benthic detritivore.〔http://paleobiology.si.edu/burgess/canadia.html〕 ''Canadia'' is thought to have swum above the seafloor as a primary means of locomotion by beating its numerous notosetae. It would also have had the ability to creep along the seafloor using the ventral counterpart of the notopodia, which are termed neuropodia (in reference to the proximity to the paired, ventral nerve cords characteristic of annelids). ''Canadia'' grew to 2-8 inches (5-20 centimeters) long.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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