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Eurysphaeridium
From Fensome et al., 2019:
"Eurysphaeridium", Wilson in Slimani, 1994, p.77.
Name not validly published: no description. See discussion under Neoeurysphaeridium.
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Original description: [Slimani, 1994, p. 77] (as Neoeurysphaeridium) (translated from French):
Derivation of the name:
Greek: neo, new; Eurysphaeridium, see synonymy below.
Synonymy:
?1974: Eurysphaeridium g. nov. in Wilson, p. 383.
Diagnosis:
Skolochorate, gonyaulacoid cyst. The central body is subspheroidal to ellipsoidal, devoid of parasutural reliefs and bears an apical protrusion and intratabular processes. The precingulate and postcingulate processes, one per plate, are tubular, very wide, closed or open distally and occupy almost all the intratabular surfaces while the apical, paracingulate, parasulcal and antapical processes are smaller, thinner, simple solid or hollow. The antapical process and/or rare (1-3) precingulate and postcingulate processes often undergo a change in size and shape. The periphragm and endophragm are attached between the processes. The paratabulation is of the gonyaulacoid type, conforming to the following formula: 4', 5'', 6c, 4-5''', 3-5s, 1p, 1''''. The archaeopyle is precingulate of the P type (only 3''), the operculum is free. The paracingulum and parasulcus are usually indicated by 2-3 simple processes per plate.
Type species:
Neoeurysphaeridium glabrum sp. nov. Upper Campanian - early lower Maastrichtian Turnhout and Maastricht region.
Comparison:
Neoeurysphaeridium g. nov. and Achilleodinium EATON (1976) resemble each other by the presence of a distinctly precingulate P-type archaeopyle (3'') and by the similar arrangement of the large and small processes; but they are distinguished by the presence in Neoeurysphaeridium of an apical protrusion and by the variability of size and shape especially within the precingulate and postcingulate processes; the basal margins of the large processes are much better defined than in Achilleodinium. Florentinia DAVEY & VERDIER (1973) emend. DUXBURY (1980) is defined by a variable type archaeopyle tA+P or P, but species of this genus that have the P-type archaeopyle differ from Neoeurysphaeridium by the absence of an apical protrusion and by the presence of fissures between the apical and precingulate paraplates. It is for this last reason that LENTIN and WILLIAMS (1981: p. 1) and (1985: p. 2) do not retain the synonymy between Achilleodinium and Florentinia proposed by DUXBURY (1980: p. 119), (1983: p. 46) and BELOW (1982c: p. 7). Hystrichokolpoma KLUMPP (1953) is very clearly distinguished from Neoeurysphaeridium g. nov. among other things by its apical archaeopyle.
"Eurysphaeridium", Wilson in Slimani, 1994, p.77.
Name not validly published: no description. See discussion under Neoeurysphaeridium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Slimani, 1994, p. 77] (as Neoeurysphaeridium) (translated from French):
Derivation of the name:
Greek: neo, new; Eurysphaeridium, see synonymy below.
Synonymy:
?1974: Eurysphaeridium g. nov. in Wilson, p. 383.
Diagnosis:
Skolochorate, gonyaulacoid cyst. The central body is subspheroidal to ellipsoidal, devoid of parasutural reliefs and bears an apical protrusion and intratabular processes. The precingulate and postcingulate processes, one per plate, are tubular, very wide, closed or open distally and occupy almost all the intratabular surfaces while the apical, paracingulate, parasulcal and antapical processes are smaller, thinner, simple solid or hollow. The antapical process and/or rare (1-3) precingulate and postcingulate processes often undergo a change in size and shape. The periphragm and endophragm are attached between the processes. The paratabulation is of the gonyaulacoid type, conforming to the following formula: 4', 5'', 6c, 4-5''', 3-5s, 1p, 1''''. The archaeopyle is precingulate of the P type (only 3''), the operculum is free. The paracingulum and parasulcus are usually indicated by 2-3 simple processes per plate.
Type species:
Neoeurysphaeridium glabrum sp. nov. Upper Campanian - early lower Maastrichtian Turnhout and Maastricht region.
Comparison:
Neoeurysphaeridium g. nov. and Achilleodinium EATON (1976) resemble each other by the presence of a distinctly precingulate P-type archaeopyle (3'') and by the similar arrangement of the large and small processes; but they are distinguished by the presence in Neoeurysphaeridium of an apical protrusion and by the variability of size and shape especially within the precingulate and postcingulate processes; the basal margins of the large processes are much better defined than in Achilleodinium. Florentinia DAVEY & VERDIER (1973) emend. DUXBURY (1980) is defined by a variable type archaeopyle tA+P or P, but species of this genus that have the P-type archaeopyle differ from Neoeurysphaeridium by the absence of an apical protrusion and by the presence of fissures between the apical and precingulate paraplates. It is for this last reason that LENTIN and WILLIAMS (1981: p. 1) and (1985: p. 2) do not retain the synonymy between Achilleodinium and Florentinia proposed by DUXBURY (1980: p. 119), (1983: p. 46) and BELOW (1982c: p. 7). Hystrichokolpoma KLUMPP (1953) is very clearly distinguished from Neoeurysphaeridium g. nov. among other things by its apical archaeopyle.