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Disphaerogena lemniscata
Disphaerogena lemniscata (Corradini 1973) Lentin and Williams 1989
Originally Cordosphaeridium, subsequently Cordosphaeridium?, thirdly Plethysyrinx, fourthly Cyclapophysis, fifthly (and now) Disphaerogena.
Holotype: Corradini, 1973, pl.22, fig.5
Locus typicus: Castel di Casio, Bologna, Italy
Stratum typicum: Late Cretaceous-Paleocene
Original diagnosis: Corradini, 1973, p.153: Cordosphaeridium lemniscatum
Ellipsoidal celntral body with wall composed of smooth endophragm and roughly fibrous periphragm. Wide taeniate processes, strongly fibrous, with undulose margins but more often united distally by fibrous-reticulate ribbons. Apical and antapical processes often recognizable. Archeopyle, when present, precingular in position.
Dimensions: Holotype: diameter of the central body 56x58 Ám, length of processes 20-30 Ám. Range: diameter of the central body 38-(49)-58x52-(62)-70 Ám, length of processes 15-30 Ám.
Original description: Corradini, 1973, p. 153: Cordosphaeridium lemniscatum
The test possesses a thick (2Á) endophragm. From the strongly fibrous periphragnl arise taeniate processes composed by fibres that get distally frayed when processes present undulose margins. Processes are distallv expanded and usually connected by wide fibrousreticulate ribbons. The processes seem to reflect, on the central body, the tabulation 3", 6", ?c, 5""", 1p, 1"""". Process 1" is generally narrow and truncated; 2" and 3" are also narrow but sometimes joined by a fibrous membrane, distal margins being connected by a ribbon-like membrane. The same type of connection is present between precingular and postcingular processes. Generallv 1" is joined distally by a fibrous ribbon with 1"""; the same for the others. 6" seems to be connected, in many cases with the ribbon joining 5" to 5""".
lp is normally truncated distally and shows fibrous margin. The antapical process. when recognizable, is roughly tubiform and extends distally in a sort of fibrous brush. Archeopyle formed by the loss of a wide precingular plate.
Affinities:
Corradini, 1973, p. 153: Cordosphaeridium lemniscatum
C. Iemniscatum shows a high intraspecific variability both in the shape of central body, which is more large than high, and in the size of the processes and in developement of the ribbon-like membrans. Another character, difficult to state, is given by the apical and antapical processes which often are not recognizable. The new species is similar in shape, size of processes and general appearence of the test, to C. inodes (Klumpp) and even more to C. filosum Wilson (1967) and to Form F of Evitt (1961).
The latter taxa (probably consoecific, according to Wilson), differs from C. lemniscatum only in the lack of the large fibrous-reticulate ribbons which are typical of the new species. It is interesting to note that some specimens show an antapical bulge on the inner body, which, along with the high degree of differentiation of apical and antapical processes, is typical of Lanternosphaeridium. This confirms the close relationship between Lanternosphaeridium and Cordosphaeridium already pointed out by Morgenroth (1966) and Gocht (1969). Pending a revision which confirms and explains definitely the characters and the boundaries between these two genera I prefer to regard the new species as belonging to Cordosphaeridium.
Originally Cordosphaeridium, subsequently Cordosphaeridium?, thirdly Plethysyrinx, fourthly Cyclapophysis, fifthly (and now) Disphaerogena.
Holotype: Corradini, 1973, pl.22, fig.5
Locus typicus: Castel di Casio, Bologna, Italy
Stratum typicum: Late Cretaceous-Paleocene
Original diagnosis: Corradini, 1973, p.153: Cordosphaeridium lemniscatum
Ellipsoidal celntral body with wall composed of smooth endophragm and roughly fibrous periphragm. Wide taeniate processes, strongly fibrous, with undulose margins but more often united distally by fibrous-reticulate ribbons. Apical and antapical processes often recognizable. Archeopyle, when present, precingular in position.
Dimensions: Holotype: diameter of the central body 56x58 Ám, length of processes 20-30 Ám. Range: diameter of the central body 38-(49)-58x52-(62)-70 Ám, length of processes 15-30 Ám.
Original description: Corradini, 1973, p. 153: Cordosphaeridium lemniscatum
The test possesses a thick (2Á) endophragm. From the strongly fibrous periphragnl arise taeniate processes composed by fibres that get distally frayed when processes present undulose margins. Processes are distallv expanded and usually connected by wide fibrousreticulate ribbons. The processes seem to reflect, on the central body, the tabulation 3", 6", ?c, 5""", 1p, 1"""". Process 1" is generally narrow and truncated; 2" and 3" are also narrow but sometimes joined by a fibrous membrane, distal margins being connected by a ribbon-like membrane. The same type of connection is present between precingular and postcingular processes. Generallv 1" is joined distally by a fibrous ribbon with 1"""; the same for the others. 6" seems to be connected, in many cases with the ribbon joining 5" to 5""".
lp is normally truncated distally and shows fibrous margin. The antapical process. when recognizable, is roughly tubiform and extends distally in a sort of fibrous brush. Archeopyle formed by the loss of a wide precingular plate.
Affinities:
Corradini, 1973, p. 153: Cordosphaeridium lemniscatum
C. Iemniscatum shows a high intraspecific variability both in the shape of central body, which is more large than high, and in the size of the processes and in developement of the ribbon-like membrans. Another character, difficult to state, is given by the apical and antapical processes which often are not recognizable. The new species is similar in shape, size of processes and general appearence of the test, to C. inodes (Klumpp) and even more to C. filosum Wilson (1967) and to Form F of Evitt (1961).
The latter taxa (probably consoecific, according to Wilson), differs from C. lemniscatum only in the lack of the large fibrous-reticulate ribbons which are typical of the new species. It is interesting to note that some specimens show an antapical bulge on the inner body, which, along with the high degree of differentiation of apical and antapical processes, is typical of Lanternosphaeridium. This confirms the close relationship between Lanternosphaeridium and Cordosphaeridium already pointed out by Morgenroth (1966) and Gocht (1969). Pending a revision which confirms and explains definitely the characters and the boundaries between these two genera I prefer to regard the new species as belonging to Cordosphaeridium.