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Amphorosphaeridium majus
Amphorosphaeridium majus, (Lejeune-Carpentier, 1940, p. B220–B221; text-fig.13), Lejeune-Carpentier and Sarjeant, 1981, p.12. Emendation: Lejeune-Carpentier and Sarjeant, 1981, p.12
NOW Exochosphaeridium. Originally Hystrichosphaeridium, subsequently Polysphaeridium?, thirdly Cordosphaeridium, fourthly Dapsilidinium? (combination not validly published), fifthly Amphorosphaeridium, sixthly (and now) Exochosphaeridium.
Taxonomic junior synonyms: Baltisphaeridium (as Exochosphaeridium) bifidum and Exochosphaeridium bifidum var. involutum (as Exochosphaeridium bifidum subsp. involutum), both according to Peyrot (2011, p.284).
Holotype: Lejeune-Carpentier, 1940, text-fig.13; Streel et al., 1977, pl.1, fig.7; Lejeune-Carpentier and Sarjeant, 1981, pl.2, figs.6–7; text-fig.7.
Age: Late Cretaceous.
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Supplemental description:
Corradini, 1973, p. 149:
Description:
Test subspherical, composed of thick, smooth or slightly punctate endophragm and smooth to slightly fibrous periphragm from which arise tubiform, lemniscate or taeniate processes. They have fairly broad bases and are distally aculeate or secate, sometimes branched. The length of the processes not vary considerably in the same specimen and rarely exceed half the diameter of the central body. The width on the contrary, may vary considerably. The number of processes normally varies between 40 and 60.
Precingular archeopyle horse-shoe shaped.
Dimensions:
Diameter of the central body 55-(61)-70x60-(63)-70 µm, length of the processes 18-(23)-30 µm.
Remarks:
There are no differences between Northern Apennines specimens and those described by Lejeune-Carpentier (1940) as Hystrichosphaeridium major from Upper Cretaceous flints of Belgium. This species, however, belong to the genus Cordosphaeridium owing to the shape of the archeopyle and to the position of coupled processes around the sagittal line. Therefore I do not agree with Davey & Williams (1966, 1969) which have transferred, even if dubitatively, the species to their genus Polysphaeridium probably on the bases of the high number of processes carried by these forms. The high number of processes is here not considered sufficient to take this species out of the genus Cordosphaeridium. The high variability of the number of processes of Cordosphaeridium may possibly be accounted to the working hypotesis of the double tabulation recently proposed by Gocht (1969, p. 3641) for C. inodes (Klumpp). Thanks to the double tabulation, intratabular, sutural and gonal processes coexist in the tabulation of Cordosphaeridium and for this reason it is easy to explain their high number. This high number of processes makes it extremely difficult for the reflected tabulation to be determined. However, I believe that this tabulation could be.quite similar to that of C. inodes, chiefly in epitractal area. An attempt to reconstruct the tabulation has been made studying about 40 specimens and the result is a reflected tabulation like 3", 6"", 6c, 6""", 1p, 1"""", and a variable number of sulcal plates. However, it is impossible to solve definitely this problem because of the great variability in the number of the processes chiefly as far as the ventral surface is concerned. As by C. commune sp. nov., the tabulation here proposed is therefore mostly hypothctical.
To conclude, it must be pointed out that C. major differs from C. commune only in having a higher number of processes, which are, however, shorter, and a less granular central body.
NOW Exochosphaeridium. Originally Hystrichosphaeridium, subsequently Polysphaeridium?, thirdly Cordosphaeridium, fourthly Dapsilidinium? (combination not validly published), fifthly Amphorosphaeridium, sixthly (and now) Exochosphaeridium.
Taxonomic junior synonyms: Baltisphaeridium (as Exochosphaeridium) bifidum and Exochosphaeridium bifidum var. involutum (as Exochosphaeridium bifidum subsp. involutum), both according to Peyrot (2011, p.284).
Holotype: Lejeune-Carpentier, 1940, text-fig.13; Streel et al., 1977, pl.1, fig.7; Lejeune-Carpentier and Sarjeant, 1981, pl.2, figs.6–7; text-fig.7.
Age: Late Cretaceous.
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Supplemental description:
Corradini, 1973, p. 149:
Description:
Test subspherical, composed of thick, smooth or slightly punctate endophragm and smooth to slightly fibrous periphragm from which arise tubiform, lemniscate or taeniate processes. They have fairly broad bases and are distally aculeate or secate, sometimes branched. The length of the processes not vary considerably in the same specimen and rarely exceed half the diameter of the central body. The width on the contrary, may vary considerably. The number of processes normally varies between 40 and 60.
Precingular archeopyle horse-shoe shaped.
Dimensions:
Diameter of the central body 55-(61)-70x60-(63)-70 µm, length of the processes 18-(23)-30 µm.
Remarks:
There are no differences between Northern Apennines specimens and those described by Lejeune-Carpentier (1940) as Hystrichosphaeridium major from Upper Cretaceous flints of Belgium. This species, however, belong to the genus Cordosphaeridium owing to the shape of the archeopyle and to the position of coupled processes around the sagittal line. Therefore I do not agree with Davey & Williams (1966, 1969) which have transferred, even if dubitatively, the species to their genus Polysphaeridium probably on the bases of the high number of processes carried by these forms. The high number of processes is here not considered sufficient to take this species out of the genus Cordosphaeridium. The high variability of the number of processes of Cordosphaeridium may possibly be accounted to the working hypotesis of the double tabulation recently proposed by Gocht (1969, p. 3641) for C. inodes (Klumpp). Thanks to the double tabulation, intratabular, sutural and gonal processes coexist in the tabulation of Cordosphaeridium and for this reason it is easy to explain their high number. This high number of processes makes it extremely difficult for the reflected tabulation to be determined. However, I believe that this tabulation could be.quite similar to that of C. inodes, chiefly in epitractal area. An attempt to reconstruct the tabulation has been made studying about 40 specimens and the result is a reflected tabulation like 3", 6"", 6c, 6""", 1p, 1"""", and a variable number of sulcal plates. However, it is impossible to solve definitely this problem because of the great variability in the number of the processes chiefly as far as the ventral surface is concerned. As by C. commune sp. nov., the tabulation here proposed is therefore mostly hypothctical.
To conclude, it must be pointed out that C. major differs from C. commune only in having a higher number of processes, which are, however, shorter, and a less granular central body.