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Stiphrosphaeridium
From Williams et al., 2017:
[Stiphrosphaeridium, Davey, 1982, p. 16
Although the "type species" was not validly transferred by Davey (1982b, p.16,35), the generic name Stiphrosphaeridium was validly published by that author since it is based on a previously validly published species name (I.C.N. Article 40.3).
Type species: Stiphrosphaeridium dictyophorum, (Cookson and Eisenack, 1958), Davey, 1982
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Original description: [Davey 1982]:
Diagnosis:
Shape: The body is sphaerical to subsphaerical in shape with only minor dorso- ventral flattening.
Wall: The cyst wall is apparently two- layered, the two layers being closely appressed except where the periphragm alone forms the processes. The surface is smooth to scabrate.
Paratabulation: Parasutures not observed.
Processes: The plate- centred processes are solid and fenestrate. Paracingular processes are absent. The pre-, postcingular (2-6```) and antapical processes are the largest but do vary in size depending on their position on the cyst. The processes may be solid for most of their length before becoming fenestrate, or the fenestrations may extend down to the body surface. Distally these larger processes each terminate in a more or less complete circular trabeculum; in the smaller process (1-4`, 1ps, 1p) the trabeculae are sometimes incompletely developed. The process formula is 4`, 6``, 6```, 1p, 1````, 1ps, plus 0-4s.
Archaeopyle: An apical archaeopyle is developed by the apical paraplates as a unit (Type A, total). The archaeopyle has a strongly zig-zag margin.
Remarks:
An alternative way of defining most of the processes is to describe them as fenestrate funnels which may become solid proximally.
Affinities:
Stiphrosphaeridium is considered to be most closely related to Systematophora and differs principally by never having paracingular processes. Processes occupying the major plate series (i.e. pre-, postcingular and antapical) of Systematophora are never solid, one per paraplate, but always form annulate complexes which proximally typically extend over a large proportion of a paraplate. It is possible to interpret the larger processes of Stiphrosphaeridium, when they are fenestrate down to the cyst wall, as representing narrow or reduced annulate complexes. The processes of Oligosphaeridium are similarly distributed on the cyst surface but are tubiform.
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Modified description:
Stover and Williams, 1987, p. 203:
Synopsis:
Cysts skolochorate, body subspherical and bears 17 to 23 intratabular processes with mostly solid stems and hollow funnel-shaped, fenestrate distal expansions; cingular processes absent, adjacent processes not connected by trabeculae; paratabulation indicated by type [4A] apical archaeopyle and by processes; formula: 4`, 6``, 0c, 5-6```, 1p, 1```` and 1-5s; operculum free.
Description:
Shape: Body subspherical.
Wall relationships: Autophragm only or with endophragm and periphragm; when two-layered, walls are appressed except where periphragm forms processes.
Wall features: Intratabular processes funnel-shaped with generally solid stems and hollow, fenestrate, expanded distal ends; adjacent processes not connected by trabeculae. Cyst body smooth to scabrate.
Archaeopyle: Apical, type [4A], principal archaeopyle suture zigzag; operculum free.
Paratabulation: indicated by archaeopyle and by intratabular processes; formula: 4`, 6``, 0c, 5-6```, 1p. 1```` and 1-5s.
Paracingulum: Indicated by absence of processes.
Parasulcus: Indicated anteriorly by the sulcal notch and posteriorly by the posterior sulcal process; up to four additional sulcal processes may be present.
Affinities:
Stiphrosphaeridium differs from Oligosphaeridium Davey and Williams in Davey et al. 1966 emended Davey 1982 in having processes with solid stems and from Rigaudella Below 1982 in not having the processes interconnected by trabeculae. Surculosphaeridium Davey et al. 1966 emended Davey 1982, which also possesses processes with solid stems, has cingular processes which are branched rather than fenestrate distally.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Stiphrosphaeridium Davey, 1982b. Stover and Williams (1987, p.203) provided the following synopsis. Cysts skolochorate, body subspherical and bears 17 to 23 intratabular processes with mostly solid stems and hollow funnel-shaped, fenestrate distal expansions; cingular processes absent, adjacent processes not connected by trabeculae; paratabulation indicated by type (4A) apical archeopyle and by processes; formula: 4`, 6", 0c, 5-6```, 1p, 1```` and 1-5s: operculum free.
[Stiphrosphaeridium, Davey, 1982, p. 16
Although the "type species" was not validly transferred by Davey (1982b, p.16,35), the generic name Stiphrosphaeridium was validly published by that author since it is based on a previously validly published species name (I.C.N. Article 40.3).
Type species: Stiphrosphaeridium dictyophorum, (Cookson and Eisenack, 1958), Davey, 1982
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Davey 1982]:
Diagnosis:
Shape: The body is sphaerical to subsphaerical in shape with only minor dorso- ventral flattening.
Wall: The cyst wall is apparently two- layered, the two layers being closely appressed except where the periphragm alone forms the processes. The surface is smooth to scabrate.
Paratabulation: Parasutures not observed.
Processes: The plate- centred processes are solid and fenestrate. Paracingular processes are absent. The pre-, postcingular (2-6```) and antapical processes are the largest but do vary in size depending on their position on the cyst. The processes may be solid for most of their length before becoming fenestrate, or the fenestrations may extend down to the body surface. Distally these larger processes each terminate in a more or less complete circular trabeculum; in the smaller process (1-4`, 1ps, 1p) the trabeculae are sometimes incompletely developed. The process formula is 4`, 6``, 6```, 1p, 1````, 1ps, plus 0-4s.
Archaeopyle: An apical archaeopyle is developed by the apical paraplates as a unit (Type A, total). The archaeopyle has a strongly zig-zag margin.
Remarks:
An alternative way of defining most of the processes is to describe them as fenestrate funnels which may become solid proximally.
Affinities:
Stiphrosphaeridium is considered to be most closely related to Systematophora and differs principally by never having paracingular processes. Processes occupying the major plate series (i.e. pre-, postcingular and antapical) of Systematophora are never solid, one per paraplate, but always form annulate complexes which proximally typically extend over a large proportion of a paraplate. It is possible to interpret the larger processes of Stiphrosphaeridium, when they are fenestrate down to the cyst wall, as representing narrow or reduced annulate complexes. The processes of Oligosphaeridium are similarly distributed on the cyst surface but are tubiform.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 203:
Synopsis:
Cysts skolochorate, body subspherical and bears 17 to 23 intratabular processes with mostly solid stems and hollow funnel-shaped, fenestrate distal expansions; cingular processes absent, adjacent processes not connected by trabeculae; paratabulation indicated by type [4A] apical archaeopyle and by processes; formula: 4`, 6``, 0c, 5-6```, 1p, 1```` and 1-5s; operculum free.
Description:
Shape: Body subspherical.
Wall relationships: Autophragm only or with endophragm and periphragm; when two-layered, walls are appressed except where periphragm forms processes.
Wall features: Intratabular processes funnel-shaped with generally solid stems and hollow, fenestrate, expanded distal ends; adjacent processes not connected by trabeculae. Cyst body smooth to scabrate.
Archaeopyle: Apical, type [4A], principal archaeopyle suture zigzag; operculum free.
Paratabulation: indicated by archaeopyle and by intratabular processes; formula: 4`, 6``, 0c, 5-6```, 1p. 1```` and 1-5s.
Paracingulum: Indicated by absence of processes.
Parasulcus: Indicated anteriorly by the sulcal notch and posteriorly by the posterior sulcal process; up to four additional sulcal processes may be present.
Affinities:
Stiphrosphaeridium differs from Oligosphaeridium Davey and Williams in Davey et al. 1966 emended Davey 1982 in having processes with solid stems and from Rigaudella Below 1982 in not having the processes interconnected by trabeculae. Surculosphaeridium Davey et al. 1966 emended Davey 1982, which also possesses processes with solid stems, has cingular processes which are branched rather than fenestrate distally.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Stiphrosphaeridium Davey, 1982b. Stover and Williams (1987, p.203) provided the following synopsis. Cysts skolochorate, body subspherical and bears 17 to 23 intratabular processes with mostly solid stems and hollow funnel-shaped, fenestrate distal expansions; cingular processes absent, adjacent processes not connected by trabeculae; paratabulation indicated by type (4A) apical archeopyle and by processes; formula: 4`, 6", 0c, 5-6```, 1p, 1```` and 1-5s: operculum free.