Hemiphragmoceratidae

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m (Protected "Hemiphragmoceratidae" ([move=sysop] (indefinite)))
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The Middle to Upper Silurian (possibly to Middle Devonian) Hemiphragmoceratidae were a very distinctive family of oncocerid cephalopods. At maturity, large lappets developed at the aperture of the body cavity, restricting the shell's opening. Exactly what sort of animal inhabited such a shell and how it lived are currently unknown.
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'''Characters''' (from Sweet 1964): Compressed endogastric brevicones, curved adapically, straight adorally, with ventral, nummuloidal, actinosiphonate siphuncle and elaborately visored aperture. Actinosiphonate deposits continuous between segments. Mature peristome with hyponomic sinus on spoutlike process, paired lateral sinuses and mid-dorsal salient.
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==Taxonomy==
  [[Oncoceratidae|<==]]Hemiphragmoceratidae
  [[Oncoceratidae|<==]]Hemiphragmoceratidae
     |--''Hemiphragmoceras'' Hyatt ''in'' Zittel 1900 [=''Hemiphraygmoceras'' (''l. c.'')] S64
     |--''Hemiphragmoceras'' Hyatt ''in'' Zittel 1900 [=''Hemiphraygmoceras'' (''l. c.'')] S64

Revision as of 00:34, 19 January 2011

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