Welcome to the Treatise on Invertebrate Paleontology!
Please enter a genera name to retrieve more information.
Proagnostus
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Agnostida
Superfamily:
Agnostoidea
Family:
Agnostidae
Formal Genus Name and Reference:
Proagnostus Butts, 1926, p. 76, Proagnostus (Paragnostacus) PENG, 1992, p. 85
Type Species:
P. bulbus, OD, lectotype (Butts, 1926, pl. 9, fig. 12, SD ROBISON, 1988, p. 41, fig. 8.12), 94867, USNM, Washington, D.C.
Images
(Click to enlarge in a new window)
.png)
Fig. 220,3a–c. *P. bulbus; a, Upper Cambrian (Dresbachian), USA (Cedar Bluff, Alabama), lectotype, exoskeleton, USNM 94867, ×10 (Resser, 1938, pl. 10, fig. 17); b,c, latest Middle Cambrian (Lejopye laevigata Zone), northern Greenland (Gustav Holm Dal, Peary Land), b, pygidium, MGUH 17.128 and c, cephalon, MGUH 17.126, ×8 (Robison, 1988, fig. 8.14–15).
Synonyms
Agnostascus
Geographic Distribution
northern Greenland; USA (Alabama), Cedaria Zone; Canada (Northwest Territories), Cedaria minor Zone; Australia (Queensland), E. eretes Zone, (Tasmania), L. laevigata Zone; China (Hunan, Guizhou), Paradamesops jimaensis-Cyclolorenzella tuma Zones, (Xinjiang), Agnostascus orientalis (=Proagnostus orientalis) Zone; Kazakhstan, Kormagnostus simplex Zone; Russia (Siberia), L. laevigata to G. stolidotus Zones.
Age Range
Beginning Stage in Treatise Usage:
upper Middle Cambrian
Beginning International Stage:
Drumian
Fraction Up In Beginning Stage:
0
Beginning Date:
504.5
Ending Stage in Treatise Usage:
lower Upper Cambrian
Ending International Stage:
Fraction Up In Ending Stage:
0
Ending Date:
493.4
Description
Cephalon narrow, trapeziform or semiovate, with nondeliquiate border furrows and with a narrow border in the cephalon and a wider, flattened border in the pygidium. Median preglabellar furrow well developed. Glabella with subquadrate to semiovate anterior lobe, F3 straight or bent strongly forward, posterior lobe with well-developed F2 furrows, glabellar culmination broadly rounded to obtusely angular, glabellar node in front of F2 furrows. Pygidial spines retral or advanced, axis with well-developed constriction across M2, F1 weakly impressed or effaced, F2 weakly impressed or absent, deflected posteriorly by strong axial node.
References
Butts, C. 1926. The Palaeozoic Rocks. In G. I. Adams, C. Butts, L. W. Stephanson, \& W. Cooke, eds., Geology of Alabama. Geological Survey of Alabama, Special Report 14. p. 41-230, pl. 3-76.
Museum or Author Information
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Agnostida
Superfamily:
Agnostoidea
Family:
Agnostidae
Formal Genus Name and Reference:
Proagnostus Butts, 1926, p. 76, Proagnostus (Paragnostacus) PENG, 1992, p. 85
Type Species:
P. bulbus, OD, lectotype (Butts, 1926, pl. 9, fig. 12, SD ROBISON, 1988, p. 41, fig. 8.12), 94867, USNM, Washington, D.C.
Images
(Click to enlarge in a new window)
Fig. 220,3a–c. *P. bulbus; a, Upper Cambrian (Dresbachian), USA (Cedar Bluff, Alabama), lectotype, exoskeleton, USNM 94867, ×10 (Resser, 1938, pl. 10, fig. 17); b,c, latest Middle Cambrian (Lejopye laevigata Zone), northern Greenland (Gustav Holm Dal, Peary Land), b, pygidium, MGUH 17.128 and c, cephalon, MGUH 17.126, ×8 (Robison, 1988, fig. 8.14–15).
Synonyms
Agnostascus
Geographic Distribution
northern Greenland; USA (Alabama), Cedaria Zone; Canada (Northwest Territories), Cedaria minor Zone; Australia (Queensland), E. eretes Zone, (Tasmania), L. laevigata Zone; China (Hunan, Guizhou), Paradamesops jimaensis-Cyclolorenzella tuma Zones, (Xinjiang), Agnostascus orientalis (=Proagnostus orientalis) Zone; Kazakhstan, Kormagnostus simplex Zone; Russia (Siberia), L. laevigata to G. stolidotus Zones.
Age Range
Beginning Stage in Treatise Usage:
upper Middle Cambrian
Beginning International Stage:
Drumian
Fraction Up In Beginning Stage:
0
Beginning Date:
504.5
Ending Stage in Treatise Usage:
lower Upper Cambrian
Ending International Stage:
Fraction Up In Ending Stage:
0
Ending Date:
493.4
Description
Cephalon narrow, trapeziform or semiovate, with nondeliquiate border furrows and with a narrow border in the cephalon and a wider, flattened border in the pygidium. Median preglabellar furrow well developed. Glabella with subquadrate to semiovate anterior lobe, F3 straight or bent strongly forward, posterior lobe with well-developed F2 furrows, glabellar culmination broadly rounded to obtusely angular, glabellar node in front of F2 furrows. Pygidial spines retral or advanced, axis with well-developed constriction across M2, F1 weakly impressed or effaced, F2 weakly impressed or absent, deflected posteriorly by strong axial node.
References
Butts, C. 1926. The Palaeozoic Rocks. In G. I. Adams, C. Butts, L. W. Stephanson, \& W. Cooke, eds., Geology of Alabama. Geological Survey of Alabama, Special Report 14. p. 41-230, pl. 3-76.