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Nemagraptus
Classification
Phylum:
Hemichordata
Class:
Pterobranchia
Order:
Graptoloidea
Superfamily:
Unknown
Family:
Dicranograptidae
Formal Genus Name and Reference:
Nemagraptus EMMONS, 1855, p. 109
Type Species:
*Graptolithus gracilis Hall, 1847, p. 274, =Nemagraptus elegans Emmons, 1855, p. 109, SD HALL, 1868, p. 211
Images
(Click to enlarge in a new window)
Fig. 245,1a–b. *N. gracilis (Hall); 1a, AMNH 30458, lectotype; 1b, AMNH 36766, more complete specimen; Normans Kill Shales, Kenwood, New York, USA; scale bars, 1 mm (Finney, 1985a, fig. 10,1–2).——Fig. 245,1c–d. Nemagraptus sp. B, Athens Shale, Calera, Alabama, USA; 1c, OSU 32976, paired cladia on left stipe, scale bar, 1 mm; 1d, OSU 32975, showing Nemagraptus-type proximal end; scale bar, 1 mm (Finney, 1985a, fig. 27,1,3; as Amphigraptus sp. B).——Fig. 245,1e. Nemagraptus sp. A, OSU 32973, paired cladia on distal part of stipe, Athens Shale, Pratt’s syncline section, Alabama, USA, scale bar, 1 mm (Finney, 1985a, fig. 273; as Amphigraptus sp. A).
Synonyms
Coenograptus, Geitonograptus, Helicograpsus, Ordosograptus, Stephanograptus
Geographic Distribution
Alabama, USA, worldwide
Age Range
Beginning Stage in Treatise Usage:
Middle Ordovician (Darriwilian, Corymbograptus retroflexus Biozone)
Beginning International Stage:
Darriwilian
Fraction Up In Beginning Stage:
0
Beginning Date:
469.42
Ending Stage in Treatise Usage:
Upper Ordovician (Sandbian, Nemagraptus gracilis Biozone)
Ending International Stage:
Sandbian
Fraction Up In Ending Stage:
0
Ending Date:
452.75
Description
isolated metasicula as the main synapomorphy, variable development of cladia, thecae possess considerable overlap and indications of intrathecal folds in Nemagraptus linmassiae, shorter thecae lacking introverted thecal apertures and lateral lappets in Nemagraptus gracilis, paired cladia on left stipe or distal part of stipe in some specimens
References
Emmons, Ebenezer. 1855. American Geology, Containing a Statement of the Principles of the Science, with Full Illustrations of the Characteristic American Fossils, Also an Atlas and a Geological Map of the United States. Part 2. The Taconic System. J. Munsell. Albany. 251 p., 18 pl.
Museum or Author Information
Classification
Phylum:
Hemichordata
Class:
Pterobranchia
Order:
Graptoloidea
Superfamily:
Unknown
Family:
Dicranograptidae
Formal Genus Name and Reference:
Nemagraptus EMMONS, 1855, p. 109
Type Species:
*Graptolithus gracilis Hall, 1847, p. 274, =Nemagraptus elegans Emmons, 1855, p. 109, SD HALL, 1868, p. 211
Images
(Click to enlarge in a new window)
Fig. 245,1a–b. *N. gracilis (Hall); 1a, AMNH 30458, lectotype; 1b, AMNH 36766, more complete specimen; Normans Kill Shales, Kenwood, New York, USA; scale bars, 1 mm (Finney, 1985a, fig. 10,1–2).——Fig. 245,1c–d. Nemagraptus sp. B, Athens Shale, Calera, Alabama, USA; 1c, OSU 32976, paired cladia on left stipe, scale bar, 1 mm; 1d, OSU 32975, showing Nemagraptus-type proximal end; scale bar, 1 mm (Finney, 1985a, fig. 27,1,3; as Amphigraptus sp. B).——Fig. 245,1e. Nemagraptus sp. A, OSU 32973, paired cladia on distal part of stipe, Athens Shale, Pratt’s syncline section, Alabama, USA, scale bar, 1 mm (Finney, 1985a, fig. 273; as Amphigraptus sp. A).
Synonyms
Coenograptus, Geitonograptus, Helicograpsus, Ordosograptus, Stephanograptus
Geographic Distribution
Alabama, USA, worldwide
Age Range
Beginning Stage in Treatise Usage:
Middle Ordovician (Darriwilian, Corymbograptus retroflexus Biozone)
Beginning International Stage:
Darriwilian
Fraction Up In Beginning Stage:
0
Beginning Date:
469.42
Ending Stage in Treatise Usage:
Upper Ordovician (Sandbian, Nemagraptus gracilis Biozone)
Ending International Stage:
Sandbian
Fraction Up In Ending Stage:
0
Ending Date:
452.75
Description
isolated metasicula as the main synapomorphy, variable development of cladia, thecae possess considerable overlap and indications of intrathecal folds in Nemagraptus linmassiae, shorter thecae lacking introverted thecal apertures and lateral lappets in Nemagraptus gracilis, paired cladia on left stipe or distal part of stipe in some specimens
References
Emmons, Ebenezer. 1855. American Geology, Containing a Statement of the Principles of the Science, with Full Illustrations of the Characteristic American Fossils, Also an Atlas and a Geological Map of the United States. Part 2. The Taconic System. J. Munsell. Albany. 251 p., 18 pl.