Welcome to the Treatise on Invertebrate Paleontology!
Please enter a genera name to retrieve more information.
Amorphognathus
Classification
Phylum:
Conodonta
Class:
Conodonta
Order:
Conodontophorida
Superfamily:
Prioniodontacea
Family:
Balognathidae
Formal Genus Name and Reference:
Amorphognathus Branson & MEHL, 1933b, p. 126
Type Species:
A. ordovicica, OD
Images
(Click to enlarge in a new window)
FIG. 71,1. *A. ordovicicus, U.Ord.(Maravillas F.), USA (Texas); Ia.b, sinistral Pa element, upper and lower views, X32, X35; Ic, dextral Pa element, upper view, X 32; 1d,e, sinistral Pb element, ant.lat. and lower views, X62; If, dextral Pb element, ant.-Iat. view, X62; Ig, M element, lat. view, X60; Ih, Se element, lat. view, X62; Ii, Sa element, lat. view, X62; Ij, sb element, lat. view, X 62; 1 k, Sd element, lat. view, X 62 (Bergstrom, n).
Synonyms
Ambalodus; Balognathus; Holodontus; Keislognathus; Rosagnathus; Goniodontus; Tvaerenognathus; ?Tripodontus
Geographic Distribution
N.Am.-Eu.
Age Range
Beginning Stage in Treatise Usage:
L.Ord., M.Ord
Beginning International Stage:
Tremadocian
Fraction Up In Beginning Stage:
0
Beginning Date:
486.85
Ending Stage in Treatise Usage:
U.Ord.
Ending International Stage:
Telychian
Fraction Up In Ending Stage:
100
Ending Date:
432.93
Description
Apparatus septimembrate, with morphologically different left and right elements in P positions. P a elements pastiniscaphate, greatly expanded laterally, with simple or bifid lateral processes and wide basal cavity, denticulation of upper surface of all processes restricted to central row without lateral ribs or nodes. Pb elements pastinate with well-developed posterior and lateral processes and short anterior process. M elements tertiopedate with short, weakly denticulate posterior process and longer, denticulate anterior and lateral processes. Sa elements alate with long posterior process and shorter lateral process. Sb elements tertiopedate but otherwise similar to Sa elements. Se elements bipennate with long, laterally denticulate anterior process. Sd elements quadriramate with long pOSterior and shorter anterior and lateral processes. In most species, processes of all ramiform elements laterally compressed and narrow basal cavity extending along entire length; denticulation on posterior process of " hindeodelloid" type. [Apparatus reconstruction: BERGSTROM, 1971.]
References
Bergström, S. M., , Carnes, J. B., Ethington, R. L., Votaw, R. B., & Wigley, P. B., , Epstein, A. G., & Epstein, J. B., , & Sweet, W. C., 1966, Conodonts from the Lexington Limestone (Middle Ordovician) of Kentucky and its lateral equivalents in Ohio and Indiana: Bull. Am. Paleontol., v. 50, no. 229, p. 271-441, 13 text-fig., pl. 28-35.
Museum or Author Information
Classification
Phylum:
Conodonta
Class:
Conodonta
Order:
Conodontophorida
Superfamily:
Prioniodontacea
Family:
Balognathidae
Formal Genus Name and Reference:
Amorphognathus Branson & MEHL, 1933b, p. 126
Type Species:
A. ordovicica, OD
Images
(Click to enlarge in a new window)
FIG. 71,1. *A. ordovicicus, U.Ord.(Maravillas F.), USA (Texas); Ia.b, sinistral Pa element, upper and lower views, X32, X35; Ic, dextral Pa element, upper view, X 32; 1d,e, sinistral Pb element, ant.lat. and lower views, X62; If, dextral Pb element, ant.-Iat. view, X62; Ig, M element, lat. view, X60; Ih, Se element, lat. view, X62; Ii, Sa element, lat. view, X62; Ij, sb element, lat. view, X 62; 1 k, Sd element, lat. view, X 62 (Bergstrom, n).
Synonyms
Ambalodus; Balognathus; Holodontus; Keislognathus; Rosagnathus; Goniodontus; Tvaerenognathus; ?Tripodontus
Geographic Distribution
N.Am.-Eu.
Age Range
Beginning Stage in Treatise Usage:
L.Ord., M.Ord
Beginning International Stage:
Tremadocian
Fraction Up In Beginning Stage:
0
Beginning Date:
486.85
Ending Stage in Treatise Usage:
U.Ord.
Ending International Stage:
Telychian
Fraction Up In Ending Stage:
100
Ending Date:
432.93
Description
Apparatus septimembrate, with morphologically different left and right elements in P positions. P a elements pastiniscaphate, greatly expanded laterally, with simple or bifid lateral processes and wide basal cavity, denticulation of upper surface of all processes restricted to central row without lateral ribs or nodes. Pb elements pastinate with well-developed posterior and lateral processes and short anterior process. M elements tertiopedate with short, weakly denticulate posterior process and longer, denticulate anterior and lateral processes. Sa elements alate with long posterior process and shorter lateral process. Sb elements tertiopedate but otherwise similar to Sa elements. Se elements bipennate with long, laterally denticulate anterior process. Sd elements quadriramate with long pOSterior and shorter anterior and lateral processes. In most species, processes of all ramiform elements laterally compressed and narrow basal cavity extending along entire length; denticulation on posterior process of " hindeodelloid" type. [Apparatus reconstruction: BERGSTROM, 1971.]
References
Bergström, S. M., , Carnes, J. B., Ethington, R. L., Votaw, R. B., & Wigley, P. B., , Epstein, A. G., & Epstein, J. B., , & Sweet, W. C., 1966, Conodonts from the Lexington Limestone (Middle Ordovician) of Kentucky and its lateral equivalents in Ohio and Indiana: Bull. Am. Paleontol., v. 50, no. 229, p. 271-441, 13 text-fig., pl. 28-35.