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Polygonium jurassicum
Polygonium jurassicum Bucefalo Palliani et al., 1996
Holotype. Bucefalo Palliani et al. 1996: Plate 1, fig.8
Locus typicus: 50,3.50 m from the base of the Pozzale section.
Stratum typcim: Marne di Monte Serrone Formation, lowerToarcian.
Original diagnosis. Bucefalo Palliani et al. 1996, p. 160
Vesicle hollow, subspheroidal to subpolygonal. Eilyma thin and microscabrate, bearing 15 to 20 spines. The spines are smooth, hollow, simple and homomorphic. They are closed and pointed while proximally they have relatively broad bases. The spines are of differing length, are distributed on several planes on the vesicle and, because of their broad bases, impart a relatively subpolygonal outline to the vesicle. There is no communication between the spine cavity and the vesicle interior. No opening is visible.
Remarks. Bucefalo Palliani et al. 1996, p. 160
Polygonium? aster (Sarjeant 1967) Erkmen & Sarjeant 1980, the other Jurassic species of the genus Polygonium, is significantly more polygonal in shape than Polygonium jurassicum sp. nov. Moreover, Polygonium? asteronly bears 9 to 10 spines and an opening is visible. The morphological features of Polygonium jurassicum s p. nov. are illustrated in Text-Figure 3.
Dimensions: Holotype: Diameter 28.6µm; mean length of the spines 17.5 µm.
Dimensions (µm). 20 specimens measured.
Minimum Mean Maximum
Overall vesicle diameter: 17.0 22.5 27.8
Mean length of the spines: 12.6 µm
Stratigraphic Distribution. Umbria-Marche area (central Italy) and Lefkas Island (northwest Greece). Lower Toarcian, lower Dactylioceras tenuicostatum Zone. The stratigraphic range is between two calcareous nannofossil bioevents: the first occurrences of Carinolithus superbus and Discorhabdus ignotus.
Holotype. Bucefalo Palliani et al. 1996: Plate 1, fig.8
Locus typicus: 50,3.50 m from the base of the Pozzale section.
Stratum typcim: Marne di Monte Serrone Formation, lowerToarcian.
Original diagnosis. Bucefalo Palliani et al. 1996, p. 160
Vesicle hollow, subspheroidal to subpolygonal. Eilyma thin and microscabrate, bearing 15 to 20 spines. The spines are smooth, hollow, simple and homomorphic. They are closed and pointed while proximally they have relatively broad bases. The spines are of differing length, are distributed on several planes on the vesicle and, because of their broad bases, impart a relatively subpolygonal outline to the vesicle. There is no communication between the spine cavity and the vesicle interior. No opening is visible.
Remarks. Bucefalo Palliani et al. 1996, p. 160
Polygonium? aster (Sarjeant 1967) Erkmen & Sarjeant 1980, the other Jurassic species of the genus Polygonium, is significantly more polygonal in shape than Polygonium jurassicum sp. nov. Moreover, Polygonium? asteronly bears 9 to 10 spines and an opening is visible. The morphological features of Polygonium jurassicum s p. nov. are illustrated in Text-Figure 3.
Dimensions: Holotype: Diameter 28.6µm; mean length of the spines 17.5 µm.
Dimensions (µm). 20 specimens measured.
Minimum Mean Maximum
Overall vesicle diameter: 17.0 22.5 27.8
Mean length of the spines: 12.6 µm
Stratigraphic Distribution. Umbria-Marche area (central Italy) and Lefkas Island (northwest Greece). Lower Toarcian, lower Dactylioceras tenuicostatum Zone. The stratigraphic range is between two calcareous nannofossil bioevents: the first occurrences of Carinolithus superbus and Discorhabdus ignotus.