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Symphysurus
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Ptychopariida
Superfamily:
Uncertain
Family:
Nileidae
Formal Genus Name and Reference:
Symphysurus GOLDFUSS, 1843
Type Species:
Asaphus palpebrosus DALMAN, 1827; SD BARRANDE, 1852
Images
(Click to enlarge in a new window)
Fig. 267, 8. *S. (S.) palpebrosus (Dalman), M.Ord., Swed., exoskel., X1 (modified from 1).
Synonyms
Geographic Distribution
Eu.-N.Am. S.Am.
Age Range
Beginning Stage in Treatise Usage:
L.Ord.(Tremadoc.)
Beginning International Stage:
Tremadocian
Fraction Up In Beginning Stage:
0
Beginning Date:
486.85
Ending Stage in Treatise Usage:
M.Ord.
Ending International Stage:
Darriwilian
Fraction Up In Ending Stage:
0
Ending Date:
458.18
Description
Differs from Nilells in having semicircular to parabolic cephalon; strongly convex glabella, defined by well-impressed axial furrows; narrower, more convex, tapering thoracic axis; and more evenly convex pygidium, without border and with distinct axis. It differs from Barrandia in its narrower exoskeleton, and pygidium shorter than thorax; surface usually covered with fine, raised, inosculating lines (18, 114, 153, 182, 294).
References
Museum or Author Information
Classification
Phylum:
Unknown
Class:
Trilobata
Order:
Ptychopariida
Superfamily:
Uncertain
Family:
Nileidae
Formal Genus Name and Reference:
Symphysurus GOLDFUSS, 1843
Type Species:
Asaphus palpebrosus DALMAN, 1827; SD BARRANDE, 1852
Images
(Click to enlarge in a new window)
Fig. 267, 8. *S. (S.) palpebrosus (Dalman), M.Ord., Swed., exoskel., X1 (modified from 1).
Synonyms
Geographic Distribution
Eu.-N.Am. S.Am.
Age Range
Beginning Stage in Treatise Usage:
L.Ord.(Tremadoc.)
Beginning International Stage:
Tremadocian
Fraction Up In Beginning Stage:
0
Beginning Date:
486.85
Ending Stage in Treatise Usage:
M.Ord.
Ending International Stage:
Darriwilian
Fraction Up In Ending Stage:
0
Ending Date:
458.18
Description
Differs from Nilells in having semicircular to parabolic cephalon; strongly convex glabella, defined by well-impressed axial furrows; narrower, more convex, tapering thoracic axis; and more evenly convex pygidium, without border and with distinct axis. It differs from Barrandia in its narrower exoskeleton, and pygidium shorter than thorax; surface usually covered with fine, raised, inosculating lines (18, 114, 153, 182, 294).