Yanhecerida

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The Yanhecerida comprises an order of early, [[Late Cambrian]], cephalopods known from northeastern China.  The order so far contains only four genera, all included in a single family, the Yanheceratidae.   
The Yanhecerida comprises an order of early, [[Late Cambrian]], cephalopods known from northeastern China.  The order so far contains only four genera, all included in a single family, the Yanheceratidae.   
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==<small>Diagnosis</small>
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==<small>Diagnosis</small>==
The Yanhecerida, established for the Yanheceratidae, proposed by Chen and Qi, 1979, are characterized by small, laterally compressed, straight or endogastrically curved shells. Curvature is such that the ventral side is concave or the dorsal side more convex, in longitudinal profile. Septal necks range from orthochoanitic to subholochoanitic, in some loxochoanitic. Diaphragms are typically conical; their interval containing calcareous deposits in some, lacking in others.
The Yanhecerida, established for the Yanheceratidae, proposed by Chen and Qi, 1979, are characterized by small, laterally compressed, straight or endogastrically curved shells. Curvature is such that the ventral side is concave or the dorsal side more convex, in longitudinal profile. Septal necks range from orthochoanitic to subholochoanitic, in some loxochoanitic. Diaphragms are typically conical; their interval containing calcareous deposits in some, lacking in others.

Latest revision as of 18:46, 25 April 2012

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