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Devonian Fossil Gallery - Brachiopod
Brachiopoda, Articulata, Strophomenida
(Phylum, Class, Order)
Red text = needs information
Fossil identification by Jo Cox unless otherwise noted
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Chonetidae
(Family)
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Chonetinella choteauensis Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 16 mm hinge |
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Description: convexi-concave, fine radial ribs --- slight sulcus on the pedicle valve, widest at hinge |
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like Chonetinella sp. Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 14 mm wide |
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Description: convexi-concave, fine radial ribs --- slight sulcus on the pedicle valve, hinge narrower than width |
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like Chonetinella sp. Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 13 mm wide |
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Description: convexi-concave, fine radial ribs --- very convex --- hinge almost equal to width |
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Neochonetes sp. (? brazosensis) Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Identification: Charles Newsom, U. of Iowa Size: 21 mm hinge |
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Description: convexi-flat, fine radial ribs, fine growth rings --- widest at hinge. There are two kinds of specimens: one's wall thickness is much thinner. |
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Neochonetes sp. (? granulifer) Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 26 mm hinge |
#1
#2
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Description: convexi-flat, very thick, fine radial ribs --- narrow sulcus on the brachial valve is in does not reach beak or anterior edge, valve is domed to fit thickened marginal ridges of pedicle valve --- corresponding fold on the pedicle valve, valve has very thick marginal ridges --- widest at hinge --- interarea forms a "V" |
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Neochonetes sp. Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 16 mm hinge |
#3
similar to #1 except smaller with straighter sides and no wings |
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Description: convexi-flat, fine radial ribs --- deep sulcus on the brachial valve, very slight fold on the pedicle valve --- hinge almost equal to width |
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Orthotetidae
(Family)
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Derbyia crassa Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 17 mm wide |
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Description: both valves almost flat convex, fine even radial ribs --- growth rings --- hinge nearly as wide as valve |
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Strophalosiidae
(Family)
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Heteralosia slocomi Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 11 mm hinge (right) |
2 specimens |
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Description: convexi-concave --- pedicle valve very convex, growth lines have spine attachments, beak overhangs --- brachial valve is flat-ish with growth rings --- hinge is nearly as wide as valve but without interarea |
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Meekellidae
(Family)
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Cyrtina sp. Period: Devonian Stage: Frasnian Formation: Lime Creek Member: Cerro Gordo Location: Bird Hill, north central Iowa Collection: Jo Cox Size: 21 mm wide Identification: Charles Newsom, U. of Iowa Size: 8 mm hinge |
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Description: convexi-flat, radial ribs, overhanging beak --- tall pointed pedicle valve, wide shallow sulcus, wider than tall triangular interarea --- slight convex brachial valve with gentle fold --- widest at hinge. The Devonian name is Cyrtina hamiltoniae, Cyrtina crassa. The modern descendent is Cyrtina hamiltonensis. |
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