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Systematophora daveyi
Systematophora? daveyi Riding and Thomas 1988
Originally Systematophora, subsequently (and now) Systematophora?. Stancliffe and Sarjeant, 1990 considered this to be a provisionally accepted species of Systematophora.
Holotype: Riding and Thomas, 1988, pl.3, figs.8-9
Paratype: Riding and Thomas, 1988
Locus typicus: Black Head, Dorset, England
Stratum typicum: Early Kimmeridgian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Systematophora daveyi Riding and Thomas, 1988. Diagnosis from Riding and Thoma (1988), Skolochorate dinoflagellate cysts, body spherical to subspherical. Autophragm smooth to finely granulate. Paratabulation gonyaulacacean, indicted by penitabular process complexes and processes. Kofoidian process formula 4', 6", xc, 5-6"’, 1p, 1"”. Pre- and postcingular paraplates (excluding 1"’)indicated by process complexes arising from arcuate ridges which are open towards the paracingulum. Apical, paracingular, parasulcal, the first postcingular and the posterior intercalary processes arise individually. The antapical process may be annulate. Arcuate and annulate process complexes comprise several slender, solid processes which subdivide medially or distally. These multifurcate processes are typically distally trabeculate, within the process complex. The trabeculae are irregularly denticulate and may bear short spines. The apical, parasulcal, paracingular, the first postcingular and the posterior intercalary processes are slender, solid and may be multifurcate. Archeopyle apical, type (4A), operculum free. This species is not included in Amphorula or Hystrichosphaerina because the former has penitabular septa, the latter has cylindrical processes. Adnatosphaeridium caulleryi has much broader process complexes comprising slender individuals which are not distally trabeculate. A.caulleryi also lacks the incomplete, arcuate pre- and postcingular process complexes. Size: overall cyst diameter, 69.6-117.6 µm, central body diameter 40.8-69.6 µm, process length 16.8-36.0 µm.
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Original diagnosis: Riding and Thomas, 1988, p. 82
Skolochorate dinoflagellate cysts, body spherical to subspherical. Autophragm smooth to finely granulate. Paratabulation gonyaulacacean, indicated by penitabular process complexes and processes. Kofoidian process formula: 4', 6", Xc, 5-6''', 1p, 1''''. Pre- and postcingular paraplates (excluding 1''') indicated by process complexes arising from arcuate ridges which are open towards the paracingulum. Apical, paracingular, parasulcal, the first postcingular and the posterior intercalary processes arise individually. The antapical process may be annulate. Arcuate and annulate process complexes comprise several slender, solid processes which subdivide medially or distally. These multifurcate processes are typically distally trabeculate, within the process complex. The trabeculae are irregularly denticulate and may bear short spines. The apical, parasulcal, paracingular, the first postcingular and the posterior intercalary processes are slender, solid and may be multifurcate. Archeopyle apical. type (4A), operculum free.
Original description: Riding and Thomas, 1988, p. 83-84
A species of Systematophora with a spherical/subspherical, smooth to finely granulate cyst body bearing slender, solid, processes as paraplate-centered individuals or as process complexes arising from penitabular ridges. Arcuate ridges, open toward the paracingulum, characterize the pre- and postcingular regions. The latter and the normally annulate antapical ridge are surmounted by several processes which branch either medially or distally. These branches may surmount the trabeculae, which never connect neighboring complexes. The remaining processes (apical, parasulcal, para- cingular, the posterior intercalary and the first postcingular) arise individually, are slender, solid and may be deeply furcate.
Dimensions: Overall cyst diameter: 117,6 (85,3) 69,6 µm. Diameter of cyst body: 69,9 (50,3) 40,8 µm. Length of processes: 36,0 (24,4) 16,8 µm.
Affinities:
Riding and Thomas, 1988, p.86: Systematophora daveyi is characterized by the prominent, arcuate pre- and postcingular process-bearing ridges which are open towards the paracingulum (in the manner of Amphorula Dodekova 1969 and Hemiplacophora Cookson & Eisenack 1965). These characteristic features separate S. daveyi sp. nov. from all other species of Systematophora.
Systematophora daveyi sp. nov. exhibits distal trabeculae within the process complexes; Stover and Evitt (1978, p. 84) stated that Systematophora is characterized by penitabular process groups which are rarely connected distally. Despite this, the species is placed in Systematophora as the two otherwise morphologically closest chorate genera with distal trabeculae are fundamentally different in organization. Amphorula and Hystrichosphaerina Alberti 1961 exhibit penitabular septa and cylindrical processes respectively.
Davey (1982) stated that this form, identifed as Systematophora sp. 1, exhibits some variation in the complexity of the processes. He further commented that S. daveyi sp. nov. is comparable to Adnatosphaeridium caulleryi (Deflandre 1938) Williams & Downie 1969. The latter, however, has much broader process complexes comprising slender individuals which are not consistently distally trabeculate. A. caulleryi also lacks the incomplete, arcuate pre- and postcingular process complexes.
Hystrichosphaerina orbifera (Klement 1960) Stover & Evitt 1978 is also comparable to Systematophora daveyi sp. nov., but is distinguished by possessing proximally and distally circular pre- and postcingular process complexes, which are generally more complexly branched.
Amphorula delicata Van Helden 1986 is superficially similar to Systematophora daveyi, however, A. delicata exhibits relatively short pre- and postcingular septa formed by numerous delicate processes and reticulate paracingular septa.
Originally Systematophora, subsequently (and now) Systematophora?. Stancliffe and Sarjeant, 1990 considered this to be a provisionally accepted species of Systematophora.
Holotype: Riding and Thomas, 1988, pl.3, figs.8-9
Paratype: Riding and Thomas, 1988
Locus typicus: Black Head, Dorset, England
Stratum typicum: Early Kimmeridgian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Systematophora daveyi Riding and Thomas, 1988. Diagnosis from Riding and Thoma (1988), Skolochorate dinoflagellate cysts, body spherical to subspherical. Autophragm smooth to finely granulate. Paratabulation gonyaulacacean, indicted by penitabular process complexes and processes. Kofoidian process formula 4', 6", xc, 5-6"’, 1p, 1"”. Pre- and postcingular paraplates (excluding 1"’)indicated by process complexes arising from arcuate ridges which are open towards the paracingulum. Apical, paracingular, parasulcal, the first postcingular and the posterior intercalary processes arise individually. The antapical process may be annulate. Arcuate and annulate process complexes comprise several slender, solid processes which subdivide medially or distally. These multifurcate processes are typically distally trabeculate, within the process complex. The trabeculae are irregularly denticulate and may bear short spines. The apical, parasulcal, paracingular, the first postcingular and the posterior intercalary processes are slender, solid and may be multifurcate. Archeopyle apical, type (4A), operculum free. This species is not included in Amphorula or Hystrichosphaerina because the former has penitabular septa, the latter has cylindrical processes. Adnatosphaeridium caulleryi has much broader process complexes comprising slender individuals which are not distally trabeculate. A.caulleryi also lacks the incomplete, arcuate pre- and postcingular process complexes. Size: overall cyst diameter, 69.6-117.6 µm, central body diameter 40.8-69.6 µm, process length 16.8-36.0 µm.
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Original diagnosis: Riding and Thomas, 1988, p. 82
Skolochorate dinoflagellate cysts, body spherical to subspherical. Autophragm smooth to finely granulate. Paratabulation gonyaulacacean, indicated by penitabular process complexes and processes. Kofoidian process formula: 4', 6", Xc, 5-6''', 1p, 1''''. Pre- and postcingular paraplates (excluding 1''') indicated by process complexes arising from arcuate ridges which are open towards the paracingulum. Apical, paracingular, parasulcal, the first postcingular and the posterior intercalary processes arise individually. The antapical process may be annulate. Arcuate and annulate process complexes comprise several slender, solid processes which subdivide medially or distally. These multifurcate processes are typically distally trabeculate, within the process complex. The trabeculae are irregularly denticulate and may bear short spines. The apical, parasulcal, paracingular, the first postcingular and the posterior intercalary processes are slender, solid and may be multifurcate. Archeopyle apical. type (4A), operculum free.
Original description: Riding and Thomas, 1988, p. 83-84
A species of Systematophora with a spherical/subspherical, smooth to finely granulate cyst body bearing slender, solid, processes as paraplate-centered individuals or as process complexes arising from penitabular ridges. Arcuate ridges, open toward the paracingulum, characterize the pre- and postcingular regions. The latter and the normally annulate antapical ridge are surmounted by several processes which branch either medially or distally. These branches may surmount the trabeculae, which never connect neighboring complexes. The remaining processes (apical, parasulcal, para- cingular, the posterior intercalary and the first postcingular) arise individually, are slender, solid and may be deeply furcate.
Dimensions: Overall cyst diameter: 117,6 (85,3) 69,6 µm. Diameter of cyst body: 69,9 (50,3) 40,8 µm. Length of processes: 36,0 (24,4) 16,8 µm.
Affinities:
Riding and Thomas, 1988, p.86: Systematophora daveyi is characterized by the prominent, arcuate pre- and postcingular process-bearing ridges which are open towards the paracingulum (in the manner of Amphorula Dodekova 1969 and Hemiplacophora Cookson & Eisenack 1965). These characteristic features separate S. daveyi sp. nov. from all other species of Systematophora.
Systematophora daveyi sp. nov. exhibits distal trabeculae within the process complexes; Stover and Evitt (1978, p. 84) stated that Systematophora is characterized by penitabular process groups which are rarely connected distally. Despite this, the species is placed in Systematophora as the two otherwise morphologically closest chorate genera with distal trabeculae are fundamentally different in organization. Amphorula and Hystrichosphaerina Alberti 1961 exhibit penitabular septa and cylindrical processes respectively.
Davey (1982) stated that this form, identifed as Systematophora sp. 1, exhibits some variation in the complexity of the processes. He further commented that S. daveyi sp. nov. is comparable to Adnatosphaeridium caulleryi (Deflandre 1938) Williams & Downie 1969. The latter, however, has much broader process complexes comprising slender individuals which are not consistently distally trabeculate. A. caulleryi also lacks the incomplete, arcuate pre- and postcingular process complexes.
Hystrichosphaerina orbifera (Klement 1960) Stover & Evitt 1978 is also comparable to Systematophora daveyi sp. nov., but is distinguished by possessing proximally and distally circular pre- and postcingular process complexes, which are generally more complexly branched.
Amphorula delicata Van Helden 1986 is superficially similar to Systematophora daveyi, however, A. delicata exhibits relatively short pre- and postcingular septa formed by numerous delicate processes and reticulate paracingular septa.