Blakeoceras

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Genus: ''Blakeoceras''
Genus: ''Blakeoceras''
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''Blakeoceras'' is a nothoceratid with an exograstric shell consisting of a rapidly expanding phragmocone and a relatively short body chamber, such that the lower or ventral side has a convex profile. Chambers are short, septa are close-spsced. The Siphuncle is concavosiphonate, segments being more or less spool-shaped, with discontinuous actinosiphonate deposits.       
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''Blakeoceras'' is a nothoceratid with an exograstric shell consisting of a rapidly expanding phragmocone and a relatively short body chamber, such that the lower or ventral side has a convex profile. Chambers are short, septa are close-spaced. The Siphuncle is concavosiphonate, segments being more or less spool-shaped, with discontinuous actinosiphonate deposits.       
''Blakeoceras'' is probably derived from the exogastrically cyroconic Upper Silurian ''[[Perimecoceras]]'', which  has a more consistent diameter but also a siphuncle with concave segments by becoming more expansive and may have given rise to ''[[Conostrichoceras]]'' and ''[[Turnoceras]]''.
''Blakeoceras'' is probably derived from the exogastrically cyroconic Upper Silurian ''[[Perimecoceras]]'', which  has a more consistent diameter but also a siphuncle with concave segments by becoming more expansive and may have given rise to ''[[Conostrichoceras]]'' and ''[[Turnoceras]]''.

Revision as of 12:13, 6 April 2013

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