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Compositosphaeridium
From Williams et al., 2017:
[Compositosphaeridium, Dodekova, 1974, p. 25-26; Emendations: Courtinat, 1989, p. 164; Stancliffe and Sarjeant, 1990, p. 202
Nomenclatural type is the holotype of Compositosphaeridium costatum, which is a tax. jr. synonym of Hystrichosphaeridium (now Compositosphaeridium) polonicum G`berka, 1965, the original type species.
Type species: originally as Hystrichosphaeridium costatum, Davey and Williams, 1966b (pl.10, fig.4)] ; Compositosphaeridium polonicum, (Gorka, 1965), Erkmen and Sarjeant, 1980
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Original description: [Dodekova, 1974]: (Translation: Stover and Evitt, 1978, p. 33):
Diagnosis:
Ovoidal to spherical septate- trabeculate cyst bearing a definite number of intratabular and furrow processes with inconstant septate and trabeculate features. Reflected tabulation scheme: ?4`, ?a, 6``, 6c, 5```, 1p, 1pv, 1````. The cyst wall is composed of two layers - endophragm and periphragm. The endophragm makes up the inner central body - endoblast. The periphragm forms processes, the membranous septa and the trabeculae. The intratabular processes are polytubular, hollow, distally opened. The furrow processes are of varying structure and differ in form and dimension from the intratabular. Both types of processes are distally connected with inconstantly developed trabeculae and proximally - with membranous septa. The archeopyle is apical, tetratabular.
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Modified description:
Stover and Evitt 1978, p. 33:
Synopsis:
Cysts skolochorate, body subspherical with approximately 24 intratabular processes; larger processes polytubular; most processes may be joined proximally by ridges or septa and some may be connected distally by trabeculae; paratabulation gonyaulacacean, indicated by intratabular processes; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Wide intratabular processes multitubular, open distally; narrow intratabular processes generally monotubular or bitubular, closed distally. Most processes joined proximally by short membranous ridges or septa, and some processes connected distally by trabeculae; periphragm smooth.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, process formula: ?4`, 6``, 6c, 5```, 1p, 1````, 1?s.
Archeopyle: Apical, Type tA; operculum free.
Paracingulum: Indicated by slender, monotubular or bitubular, distally closed processes; bitubular processes apparently interpreted as representing a single paraplate.
Parasulcus: Indicated by one or more simple spinelike processes; anterior parasulcal process may be tubular.
Size: Small to intermediate.
Affinities:
Compositosphaeridium differs from Hystrichosphaeridium in having large polytubular processes rather than exclusively monotubular processes, and in having the processes joined proximally by ridges or septa. Such proximal connections are not present on Hystrichosphaeridium.
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Emended descriptions:
Courtinat, 1989: (Translation: LPP)
Diagnosis:
Skolochorate cyst, the body is formed by a sole autophragm, bearing tubiform processes (one per paraplate). The paracingular and parasulcal processes are more slender than those of the apical, preapical, postapical and antapical series. The paratabulation is type gonyaulacacean. The paratabulation formula is, following the Kofoid notation: 4`, ?a, 6``, 6c, 5```, 1pv````; following the Taylor-Evitt notation: A-C, K or Ku, 1i-6, au-fi, II-V, X, Y, ?Z. The operculum is single composite multiplated; the archaeopyle is the type (4AI). The tubiform processes are sometimes, along the lengths of their shafts, covered by folds which may continue on the surface of the autophragm. The distal ends of the processes are spinous ("crooked hairs") and the spines may be interconnected by ringtrabeculae. The processes are never interconnected by trabeculae.
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Stancliffe and Sarjeant, 1990:
Diagnosis:
Skolochorate dinoflagellate cyst; body subspherical with a smooth to slightly granular wall consisting of an endophragm and a periphragm. The latter forms about 24 intratabular processes of which the larger are polytubular. Proximally the main processes cam be linked by ridges. Distally they are open, with spines al their comers, and may be interconnected by trabeculae. Paracingular and parasulcal processes are thinner, monotubular or bitubular, and distally closed. Paratabulation formula 0-1pr, 4`, 0-1?a, 6", 6c, 5```, 1p, 1````, 1-?s. Archeopyle apical with a zig-zag margin, without well developed auxiliary sutures. Operculum simple polyplacoid; it may incorporate a preapical paraplate as well as four apical paraplates and an anterior intercalary paraplate.
Remark:
The recent emendation by Courtinat (1989, p. 164) is here superseded, in view of inconsistencies in the diagnosis and description. He states, in justification of his emendation, that "Dodekova defined the genus as having two walls, an endophragm and a periphragm, and polytubular processes. An examination, using the S.E.M., of forms attributable to C. polonicum indicates without ambiguity that the cyst is formed by only one autophragm and that the processes are monotubes" (free translation of original Erench text).
The use of an S.E.M. to search for an inner wall of a cyst seems inappropriate. The instrument can only resolve the outer surface of a cyst and cannot prove or disprove the presence of an inner wall. A study using a transmission electron microscope (T.E.M.) would be necessary to prove the contention by Courtinat of a single wall. The accompanying illustrations (Couninat 1989, pl. 12, fig. 2 pl. 13, fig. 4), using an optical microscope show the presence of two walls, as is usual in chorate cysts. The term "autophragm" as defined by Williams, Sarjeant and Kidson (1978, p. 10) is therefore used incorrectly and the diagnosis, outlined above, retains the terms "periphragm" and "endophragm". Couninat also emends the paratabulation formula of the genus but does not mention the antapical plate (probably a typographical error?) or the sulcal plates. The process morphology, displayed by the two species assigned to Compositosphaeridium is unique and represents an evolutionary experiment in cyst form which was only temporarily successful.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Compositosphaeridium Dodekova, 1974, emend. Stancliffe and Sarjeant, 1990. According to Stancliffe and Sarjeant (1990, p.202), is a skolochorate dinoflagellate cyst: body subspherical with a smooth to slightly granular wall consisting of an endophragm and a periphragm. The latter forms about 24 intratabular processes of which the larger are polytubular. Proximally the main processes can be linked by ridges. Distally they are open, with spines at their corners, and may be interconnected by trabeculae. Paracingular and parasulcal processes are thinner, monotubular or bitubular, and distally closed. Paratabulation formula is 0-1pr, 4`, 0=1?a, 6", 6c, 5"' , 1p, 1"'' , 1-?s. Archeopyle is apical with zig-zag margin, without well developed auxiliary sutures. Operculum simple polyplacoid: it may incorporate a preapical paraplate as well as four apical paraplates and an anterior intercalary paraplate.
[Compositosphaeridium, Dodekova, 1974, p. 25-26; Emendations: Courtinat, 1989, p. 164; Stancliffe and Sarjeant, 1990, p. 202
Nomenclatural type is the holotype of Compositosphaeridium costatum, which is a tax. jr. synonym of Hystrichosphaeridium (now Compositosphaeridium) polonicum G`berka, 1965, the original type species.
Type species: originally as Hystrichosphaeridium costatum, Davey and Williams, 1966b (pl.10, fig.4)] ; Compositosphaeridium polonicum, (Gorka, 1965), Erkmen and Sarjeant, 1980
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Dodekova, 1974]: (Translation: Stover and Evitt, 1978, p. 33):
Diagnosis:
Ovoidal to spherical septate- trabeculate cyst bearing a definite number of intratabular and furrow processes with inconstant septate and trabeculate features. Reflected tabulation scheme: ?4`, ?a, 6``, 6c, 5```, 1p, 1pv, 1````. The cyst wall is composed of two layers - endophragm and periphragm. The endophragm makes up the inner central body - endoblast. The periphragm forms processes, the membranous septa and the trabeculae. The intratabular processes are polytubular, hollow, distally opened. The furrow processes are of varying structure and differ in form and dimension from the intratabular. Both types of processes are distally connected with inconstantly developed trabeculae and proximally - with membranous septa. The archeopyle is apical, tetratabular.
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Modified description:
Stover and Evitt 1978, p. 33:
Synopsis:
Cysts skolochorate, body subspherical with approximately 24 intratabular processes; larger processes polytubular; most processes may be joined proximally by ridges or septa and some may be connected distally by trabeculae; paratabulation gonyaulacacean, indicated by intratabular processes; archeopyle apical, Type tA.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Wide intratabular processes multitubular, open distally; narrow intratabular processes generally monotubular or bitubular, closed distally. Most processes joined proximally by short membranous ridges or septa, and some processes connected distally by trabeculae; periphragm smooth.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, process formula: ?4`, 6``, 6c, 5```, 1p, 1````, 1?s.
Archeopyle: Apical, Type tA; operculum free.
Paracingulum: Indicated by slender, monotubular or bitubular, distally closed processes; bitubular processes apparently interpreted as representing a single paraplate.
Parasulcus: Indicated by one or more simple spinelike processes; anterior parasulcal process may be tubular.
Size: Small to intermediate.
Affinities:
Compositosphaeridium differs from Hystrichosphaeridium in having large polytubular processes rather than exclusively monotubular processes, and in having the processes joined proximally by ridges or septa. Such proximal connections are not present on Hystrichosphaeridium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended descriptions:
Courtinat, 1989: (Translation: LPP)
Diagnosis:
Skolochorate cyst, the body is formed by a sole autophragm, bearing tubiform processes (one per paraplate). The paracingular and parasulcal processes are more slender than those of the apical, preapical, postapical and antapical series. The paratabulation is type gonyaulacacean. The paratabulation formula is, following the Kofoid notation: 4`, ?a, 6``, 6c, 5```, 1pv````; following the Taylor-Evitt notation: A-C, K or Ku, 1i-6, au-fi, II-V, X, Y, ?Z. The operculum is single composite multiplated; the archaeopyle is the type (4AI). The tubiform processes are sometimes, along the lengths of their shafts, covered by folds which may continue on the surface of the autophragm. The distal ends of the processes are spinous ("crooked hairs") and the spines may be interconnected by ringtrabeculae. The processes are never interconnected by trabeculae.
-------------------------------------------
Stancliffe and Sarjeant, 1990:
Diagnosis:
Skolochorate dinoflagellate cyst; body subspherical with a smooth to slightly granular wall consisting of an endophragm and a periphragm. The latter forms about 24 intratabular processes of which the larger are polytubular. Proximally the main processes cam be linked by ridges. Distally they are open, with spines al their comers, and may be interconnected by trabeculae. Paracingular and parasulcal processes are thinner, monotubular or bitubular, and distally closed. Paratabulation formula 0-1pr, 4`, 0-1?a, 6", 6c, 5```, 1p, 1````, 1-?s. Archeopyle apical with a zig-zag margin, without well developed auxiliary sutures. Operculum simple polyplacoid; it may incorporate a preapical paraplate as well as four apical paraplates and an anterior intercalary paraplate.
Remark:
The recent emendation by Courtinat (1989, p. 164) is here superseded, in view of inconsistencies in the diagnosis and description. He states, in justification of his emendation, that "Dodekova defined the genus as having two walls, an endophragm and a periphragm, and polytubular processes. An examination, using the S.E.M., of forms attributable to C. polonicum indicates without ambiguity that the cyst is formed by only one autophragm and that the processes are monotubes" (free translation of original Erench text).
The use of an S.E.M. to search for an inner wall of a cyst seems inappropriate. The instrument can only resolve the outer surface of a cyst and cannot prove or disprove the presence of an inner wall. A study using a transmission electron microscope (T.E.M.) would be necessary to prove the contention by Courtinat of a single wall. The accompanying illustrations (Couninat 1989, pl. 12, fig. 2 pl. 13, fig. 4), using an optical microscope show the presence of two walls, as is usual in chorate cysts. The term "autophragm" as defined by Williams, Sarjeant and Kidson (1978, p. 10) is therefore used incorrectly and the diagnosis, outlined above, retains the terms "periphragm" and "endophragm". Couninat also emends the paratabulation formula of the genus but does not mention the antapical plate (probably a typographical error?) or the sulcal plates. The process morphology, displayed by the two species assigned to Compositosphaeridium is unique and represents an evolutionary experiment in cyst form which was only temporarily successful.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Compositosphaeridium Dodekova, 1974, emend. Stancliffe and Sarjeant, 1990. According to Stancliffe and Sarjeant (1990, p.202), is a skolochorate dinoflagellate cyst: body subspherical with a smooth to slightly granular wall consisting of an endophragm and a periphragm. The latter forms about 24 intratabular processes of which the larger are polytubular. Proximally the main processes can be linked by ridges. Distally they are open, with spines at their corners, and may be interconnected by trabeculae. Paracingular and parasulcal processes are thinner, monotubular or bitubular, and distally closed. Paratabulation formula is 0-1pr, 4`, 0=1?a, 6", 6c, 5"' , 1p, 1"'' , 1-?s. Archeopyle is apical with zig-zag margin, without well developed auxiliary sutures. Operculum simple polyplacoid: it may incorporate a preapical paraplate as well as four apical paraplates and an anterior intercalary paraplate.