Ellesmerocerida

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m (Protected "Ellesmerocerida" [move=sysop])
m (Gasconadian Recovery: typo)
 
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==Taxonomic Position==
==Taxonomic Position==
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The Ellesmerocerida comprise an order of Nautiloid Cephalopods included in the superorder Plectronoceratoidea and are derived from the Plectronocerida in the Late Cambrian. The Ellesmerocerida are divided into two suborders, the Ellesmeroceratina and the Cyrtocerinina.  
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The Ellesmerocerida comprise an order of Nautiloid Cephalopods included in the superorder Plectronoceratoidea and are derived from the Plectronocerida in the Late Cambrian. The Ellesmerocerida are divided into two suborders, the Ellesmeroceratina and the [[Cyrtocerinina]].  
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Later in the Gasconadian additional modifications showed up, mainly in the aperture which in some, such as the endgastirc ''Barnseoceras'' and ''Buehleroceras'' became constricted. Other developments include the broad grooves that run along the flanks of ''Oneotoceras''.
Later in the Gasconadian additional modifications showed up, mainly in the aperture which in some, such as the endgastirc ''Barnseoceras'' and ''Buehleroceras'' became constricted. Other developments include the broad grooves that run along the flanks of ''Oneotoceras''.
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Also from the Gasconadian are the ellesmeroceratid ''Pachendocera'' which gave rise to the [[Endocerida]] through ''Proendoceras'' and ''Bassleroceras'' which belongs in the Bassleroceratidae and which gave irse to the [[Tarphycerida]]  
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Also from the Gasconadian are the ellesmeroceratid ''Pachendocera'' which gave rise to the [[Endocerida]] through ''Proendoceras'' and ''Bassleroceras'' which belongs in the Bassleroceratidae and which gave rise to the [[Tarphycerida]]
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== Post Gasconadian Expansion==
== Post Gasconadian Expansion==
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The Ellesmeroceratidae continued to the end of the Lower Ordovician (Canadian), although as a minor contribution to the total cephalopod fauna. Also continuing to the end of the Canadian are the Bassleroceratidae and Protocycloceratidae which have their beginnings in the Gasconadian ellesmeroceratids. The Protocycloceratidae apparently gave rise to the Cyclostomiceratidae in the Late Canadian (Cassinian). All belong to the Ellesmeroceratina, except perhaps the Bassleroceratidae which Rousseau Flower included in the Tarphycerida.  
The Ellesmeroceratidae continued to the end of the Lower Ordovician (Canadian), although as a minor contribution to the total cephalopod fauna. Also continuing to the end of the Canadian are the Bassleroceratidae and Protocycloceratidae which have their beginnings in the Gasconadian ellesmeroceratids. The Protocycloceratidae apparently gave rise to the Cyclostomiceratidae in the Late Canadian (Cassinian). All belong to the Ellesmeroceratina, except perhaps the Bassleroceratidae which Rousseau Flower included in the Tarphycerida.  
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Also, with its beginning early in the Middle Canadian, is the Eothinoceratidae, first of the Cyrtocerinina. ''Eothinoceras'', the sole known genus of the family gave rise in the Late Canadian to ''Bathmoceras'' the sole genus of the Bathmoceratidae which stands as a possible origin of the [[Actinocerida]]., and to the Late Ordovician [[Cyrtocerinidae]]
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Also, with its beginning early in the Middle Canadian, is the Eothinoceratidae, first of the Cyrtocerinina. ''Eothinoceras'', the sole known genus of the family gave rise in the Late Canadian to ''Bathmoceras'' the sole genus of the Bathmoceratidae which stands as a possible origin of the [[Actinocerida]]., and to the Late Ordovician [[Cyrtocerinina|Cyrtocerinidae]]
== Ellesmerocerid Derivatives==
== Ellesmerocerid Derivatives==

Latest revision as of 22:30, 20 January 2009

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