Turnoceras

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''Turnoceras'' is a nothoceratid genus (Oncocerida) characterized by depressed exogastric cyrtocones with flattened venters and strongly curved and expanded phragmocones, the lateral sides of which are straight and divergent to the aperture. The dorsal and ventral sides of body chamber become parallel resulting in a consistant height. The hyponomic sinus is lacking. Sihuncle segments, characteristic of the family, are concavosiphonate with actinosiphonate deposits.  
''Turnoceras'' is a nothoceratid genus (Oncocerida) characterized by depressed exogastric cyrtocones with flattened venters and strongly curved and expanded phragmocones, the lateral sides of which are straight and divergent to the aperture. The dorsal and ventral sides of body chamber become parallel resulting in a consistant height. The hyponomic sinus is lacking. Sihuncle segments, characteristic of the family, are concavosiphonate with actinosiphonate deposits.  
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''Turnoceras'' is similar in form to ''[[Blakeoceras]]'' from which it is apparently derived, but is more strongly curved, and to ''[[Conostrichoceras]]'' and ''[[Cyrthocerites]]'' with which it seems closely related in what could be a subfamily.
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''Turnoceras'' is similar in form to ''[[Blakeoceras]]'' from which it is apparently derived, but is more strongly curved, and to ''[[Conostichoceras]]'' and ''[[Cyrthocerites]]'' with which it seems closely related in what could be a subfamily.
''Turnoceras'', named by Foerte, 1926, has been found in the Middle Devonian of North America (NY) and central Europe (ex Czechoslovakia). The type species is ''Cyrtoceras turnus''Barrande, 1877.
''Turnoceras'', named by Foerte, 1926, has been found in the Middle Devonian of North America (NY) and central Europe (ex Czechoslovakia). The type species is ''Cyrtoceras turnus''Barrande, 1877.

Revision as of 14:41, 6 April 2013

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