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Opsidiscus
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Agnostida
Superfamily:
Eodiscoidea
Family:
Eodiscidae
Formal Genus Name and Reference:
Opsidiscus Westergård, 1950b, p. 606, nom. nov. pro Aulacodiscus Westergård, 1946, p. 26, non DOUVILLÉ, 1921
Type Species:
*Aulacodiscus bilobatus WestergÅrd, 1946, p. 26, OD, holotype (WESTERG&̊RD, 1946, pl. 1, fig. 21), 4702, SGU, Uppsala
Images
(Click to enlarge in a new window)
Fig. 253,1a,b. *O. bilobatus, upper Middle Cambrian (Lejopyge laevigata Zone), Sweden; a, holotype, cranidium, Östergotland, ×8; b, pygidium, Västergotland, × 8 (Westergård, 1946).
Synonyms
Geographic Distribution
Sweden, Russia (Siberian Platform, GornoAltayskaya), Australia (Queensland, Tasmania), India, Antarctica
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:
upper Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
0
Ending Date:
498.75
Description
Small species, like Pagetia, but has small abathochroal eye and fused facial suture. Thorax with two segments, the second segment bearing small, geniculate median spine. Pygidium with axis of two to six rings plus terminal portion but no terminal spine. Upper Middle Cambrian: Sweden, Russia (Siberian Platform, GornoAltayskaya), Australia (Queensland, Tasmania), India, Antarctica.
References
Museum or Author Information
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Agnostida
Superfamily:
Eodiscoidea
Family:
Eodiscidae
Formal Genus Name and Reference:
Opsidiscus Westergård, 1950b, p. 606, nom. nov. pro Aulacodiscus Westergård, 1946, p. 26, non DOUVILLÉ, 1921
Type Species:
*Aulacodiscus bilobatus WestergÅrd, 1946, p. 26, OD, holotype (WESTERG&̊RD, 1946, pl. 1, fig. 21), 4702, SGU, Uppsala
Images
(Click to enlarge in a new window)
Fig. 253,1a,b. *O. bilobatus, upper Middle Cambrian (Lejopyge laevigata Zone), Sweden; a, holotype, cranidium, Östergotland, ×8; b, pygidium, Västergotland, × 8 (Westergård, 1946).
Synonyms
Geographic Distribution
Sweden, Russia (Siberian Platform, GornoAltayskaya), Australia (Queensland, Tasmania), India, Antarctica
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:
upper Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
0
Ending Date:
498.75
Description
Small species, like Pagetia, but has small abathochroal eye and fused facial suture. Thorax with two segments, the second segment bearing small, geniculate median spine. Pygidium with axis of two to six rings plus terminal portion but no terminal spine. Upper Middle Cambrian: Sweden, Russia (Siberian Platform, GornoAltayskaya), Australia (Queensland, Tasmania), India, Antarctica.