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Zygospiraella
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Atrypida
Superfamily:
Atrypoidea
Family:
Atrypidae
Formal Genus Name and Reference:
Zygospiraella Nikiforova, 1961, p. 237
Type Species:
Terebratula duboisi de VERNEUL, 1845, p. 97, OD
Images
(Click to enlarge in a new window)
Fig. 949a-d. *Z. duboisi (de Verneuil), Rhuddanian, Estonia, serial sections, and reconstruction of brachidia, x5$ (Copper, 1982)., ——FIG. 949 e-j. Z. planoconvexa (Hall), Rhuddanian, eastern Canada, dorsal, ventral, lateral, anterior, posterior views, internal ventral valve, x2$ (Copper, 1982).
Synonyms
Megumatrypa, Cryptospira
Geographic Distribution
Eurasia, North America, Tasmania
Age Range
Beginning Stage in Treatise Usage:
Silurian (lower Llandovery)
Beginning International Stage:
Rhuddanian
Fraction Up In Beginning Stage:
0
Beginning Date:
443.07
Ending Stage in Treatise Usage:
Silurian (lower Llandovery)
Ending International Stage:
Rhuddanian
Fraction Up In Ending Stage:
100
Ending Date:
440.49
Description
Small, planoconvex to ventribiconvex, lacking distinct carination, small orthocline area, apical-transapical foramen, ribs continuous, anteriorly interrupted by short growth interruptions, frills absent, rectimarginate to weakly sulcate commissure, short teeth, small dental cavities, hinge plate shallow, wide cardinal pit, small crural bases, partly feathered crura, mediodorsal spiralia with fewer than 6 whorls, jugal processes tipped by small jugal plates. [Hinge plates, jugal processes, and crura as in Protatrypa, but differing in small size, convexity, lack of carination, presence of cardinal pit.]
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Atrypida
Superfamily:
Atrypoidea
Family:
Atrypidae
Formal Genus Name and Reference:
Zygospiraella Nikiforova, 1961, p. 237
Type Species:
Terebratula duboisi de VERNEUL, 1845, p. 97, OD
Images
(Click to enlarge in a new window)
Fig. 949a-d. *Z. duboisi (de Verneuil), Rhuddanian, Estonia, serial sections, and reconstruction of brachidia, x5$ (Copper, 1982)., ——FIG. 949 e-j. Z. planoconvexa (Hall), Rhuddanian, eastern Canada, dorsal, ventral, lateral, anterior, posterior views, internal ventral valve, x2$ (Copper, 1982).
Synonyms
Megumatrypa, Cryptospira
Geographic Distribution
Eurasia, North America, Tasmania
Age Range
Beginning Stage in Treatise Usage:
Silurian (lower Llandovery)
Beginning International Stage:
Rhuddanian
Fraction Up In Beginning Stage:
0
Beginning Date:
443.07
Ending Stage in Treatise Usage:
Silurian (lower Llandovery)
Ending International Stage:
Rhuddanian
Fraction Up In Ending Stage:
100
Ending Date:
440.49
Description
Small, planoconvex to ventribiconvex, lacking distinct carination, small orthocline area, apical-transapical foramen, ribs continuous, anteriorly interrupted by short growth interruptions, frills absent, rectimarginate to weakly sulcate commissure, short teeth, small dental cavities, hinge plate shallow, wide cardinal pit, small crural bases, partly feathered crura, mediodorsal spiralia with fewer than 6 whorls, jugal processes tipped by small jugal plates. [Hinge plates, jugal processes, and crura as in Protatrypa, but differing in small size, convexity, lack of carination, presence of cardinal pit.]