Armenoceras

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''Armenoceras'' was a genus of actinocerid cephalopods that lived from the Middle Ordovician to the Upper Silurian.
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'''''Armenoceras''''' is a genus of actinocerid cephalopods that lived from the Middle Ordovician to the Upper Silurian.
'''Characters''' (from Teichert 1964): Medium-sized to large straight shell. Siphuncle off-centre, large; adnation areas broad; septal necks very short, brims wide and in contact with posterior surface of septa; endosiphuncular canals well developed, commonly complex. Cameral deposits rare.
'''Characters''' (from Teichert 1964): Medium-sized to large straight shell. Siphuncle off-centre, large; adnation areas broad; septal necks very short, brims wide and in contact with posterior surface of septa; endosiphuncular canals well developed, commonly complex. Cameral deposits rare.
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==Distribution==
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From Flower, 1957.
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''Armenoceras numatai'' Endo (1932), which comes from the White Rockian age Wuting Fm of Mancheria, is the oldest known member of the genus. Numerous representative of Armenoceras have been found in the overlying Ssuyan Ls, apparently equivalent to the ''Actinoceras'' ls of Grabau and the Makkol ls of Kabayashi. 
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In North America no Armenocreas is found in beds of Chazyan age.  ''A. ehlersi'' from St Joseph Island is a ''Murrayoceras'', and the inclusion of ''A. milleri''  from the Perryville ls of Kentucky is doubtful.
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''A. brevicameratum'' from the late Trenton Catheys ls of Tennessee and ''A. vaupli'' from the equivalent Cynthiana ls of Kentucky are closely related.
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''Armenoceras'' is unknown in Eden or Masyville are units, but ''A. richmondense'' and A. madissonense'' occure in the late Richmond Whitewater and Saluda of Ohio and Indiana.    Further west, ''A. lowense'' and ''A. clermontense'' are found in the Maquoketa shale of Iowa.
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Large ''Armenoceras'' are found, sometimes in great abundance, in Red River and Richmond faunas in more western North America. Boulders of Burnam ls from the Llano Uplift, Texas, have produced large and abundant specimens of the general aspect of ''A. barnsi''.
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In southern New Mexico ''A. callaghani'', ''A. australe'', and ''A. verperal''i have been taken from the Lower Montoya Upham dolomite and Second Value formation of Red River age. Higher in the section the Upper Montoya Aleman of Richmond age has yealded ''A. lenticonstracum''.
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''A. rchardsoni'' is the most abundant and characteristic single cephalopod from the Selkirk limestone of southern Manitoba and ''A. arcticum'' and ''A. concinnum'', described by Troedsson, are found in the Cape Calhoun beds in northern Greenland.
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==Taxonomy==
==Taxonomy==
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==References==
==References==
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Flower, Rousseau H. 1957. Studies of the Actinoceratida. Memoir 2, New Mexico Bureau of Mines and Mineral Resources. Socorro, New Mexico. 
[P68] Purnell, L. R. 1968. Catalog of the Type Specimens of Invertebrate Fossils. Part I: Paleozoic Cephalopoda. ''United States National Museum Bulletin'' 262: 1-198.
[P68] Purnell, L. R. 1968. Catalog of the Type Specimens of Invertebrate Fossils. Part I: Paleozoic Cephalopoda. ''United States National Museum Bulletin'' 262: 1-198.

Latest revision as of 21:16, 28 November 2012

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