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Druggidium jubatum
Druggidium jubatum Duxbury, 1980; emend. Harding, 1986
Holotype: Duxbury, 1980, pl. 3, fig. 3.
Locus typicus: Speeton Clay, Speeton, England.
Stratum typicum: Barremian
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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.
Druggidium jubatum Duxbury, 1980, emend Harding, 1986b. According to Harding (1986b), Cyst length consisting of two-thirds hypocyst, one-third epicyst plus cingulum. Little or no dorsal compression. Differentiated autophragm as in Aldorfia aldorfensis so that the wall looks alveolate. Outer surface perforate, pseudoreticulate. High parasutural crests developed on hypocyst up to 3 µm high, much reduced on precingular paraplates to almost absent on the anterior intercalary and apical series. Paratabulation Pr, 4', 4a, 7", 7c, 6"’, 1p, 1"”, 2s. Paraplates 7c and as narrow and elongate. Archeopyle variable types 2P, 2P compound biplacoid with 3" adapically adherent, 4" free, 2P, compound biplacoid operculum, both pieces free. Paracingulum delineated by high parasutural crest posteriorly, crest more subdued anteriorly. Parasulcus with prominent flagellar scar. Large spatulate ps, narrows rapidly towards cingulum. Size: length 24-40 µm, width 21-29 µm. Width:length ratio 0.67-1.08.
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Original diagnosis: Duxbury, 1980, p. 117
A small dinoflagellate cyst with a prominent paracingulum which divides the body unequally so that the epicyst is 1/4 to 1/3 Of the overall length. Paratabulation is outlined by parasutural crests and these are low on the epicyst and high on the hypocyst. Paraplate areas and crests are thick and microperforate and possess a spongy texture. The epicystal paratabulation is indiscernible but that of the hypocyst is clear and of the formula 6''', 1p.v., 1''''. The archeopyle is precingular, mid-dorsal in position.
Observed Dimensions: Holotype 35x32 Ám. Overall 36(34)29x35(31)29 Ám.
Emended diagnosis: Harding, 1986, p.19
Shape: Ambitus rectangular, elongated anteroposteriorly, maximum cyst width across posterior paracingular parasutural crest. Cyst length unequally divided, being 2/3 hypocyst, the remainder shared equally by the paracingulum and the epicyst. Little or no dorsoventral compression.
Phragma: Differentiated autophragm (Evitt, 1985, p. 64) in the manner of Aldorfia aldorfensis (see Gocht 1975), giving an alveolar appearance to the paraplate cross-section (Pl. 1, fig. 8). Total phragmal thickness 1.0-1.5 Ám. Autophragm outer surface perforate, pseudoreticulate. High parasutural crests developed on hypocyst up to 3 Ám high), much reduced on precingular paraplates to almost absent on the anterior intercalary and apical series.
Paratabulation: Pr, 4', 4a, 7", 7c, 6''', 1p, 1'''', 2s (Kofoidian notation. Taylor-Evitt plate equivalents as shown in Figs. 1, 2). Paraplates 7c[1i] and as [ai] narrow and elongate.
Archaeopyle: Variable. Types i., iii. or iv. as listed in the emended generic diagnosis.
Paracingulum: Strongly developed, delineated by high parasutural crest posteriorly, crest more subdued anteriorly.
Parasulcus: Prominent flagellar scar. Large spatulate sulcal paraplate s[Z], narrows rapidly towards para- cingulum. Paraplates rs[Ii] and Is[Im] not differentiated.
Affinities:
Duxbury, 1980, p. 117: The spongy body texture and crestal height variation (epicystal crests markedly higher than hypocystal ones) in D. jubatum distinguish it from all previously described species. D. apicopaucicum Habib, 1973 has a scabrate to microgranulate surface with some small variation in crestal height (see Habib, 1973, text-fig. 3). D. deflandrei (Millioud, 1969) Habib, 1973 and D. rhabdoreticulatum Habib, 1973 both display what appears to be a reticular pattern, with that of the former tending to be concentrated near parasutural lines. According to Habib (1973, p. 54), the membrane of D. rhabdoreticulatum is raised above the central tract and is supported by short baculae, imparting an angularity to the outline of the cysts". Such angularity is displayed by D. jubatum, but is due to the crestal height variation rather than to any obvious body layer separation.
Holotype: Duxbury, 1980, pl. 3, fig. 3.
Locus typicus: Speeton Clay, Speeton, England.
Stratum typicum: Barremian
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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.
Druggidium jubatum Duxbury, 1980, emend Harding, 1986b. According to Harding (1986b), Cyst length consisting of two-thirds hypocyst, one-third epicyst plus cingulum. Little or no dorsal compression. Differentiated autophragm as in Aldorfia aldorfensis so that the wall looks alveolate. Outer surface perforate, pseudoreticulate. High parasutural crests developed on hypocyst up to 3 µm high, much reduced on precingular paraplates to almost absent on the anterior intercalary and apical series. Paratabulation Pr, 4', 4a, 7", 7c, 6"’, 1p, 1"”, 2s. Paraplates 7c and as narrow and elongate. Archeopyle variable types 2P, 2P compound biplacoid with 3" adapically adherent, 4" free, 2P, compound biplacoid operculum, both pieces free. Paracingulum delineated by high parasutural crest posteriorly, crest more subdued anteriorly. Parasulcus with prominent flagellar scar. Large spatulate ps, narrows rapidly towards cingulum. Size: length 24-40 µm, width 21-29 µm. Width:length ratio 0.67-1.08.
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Original diagnosis: Duxbury, 1980, p. 117
A small dinoflagellate cyst with a prominent paracingulum which divides the body unequally so that the epicyst is 1/4 to 1/3 Of the overall length. Paratabulation is outlined by parasutural crests and these are low on the epicyst and high on the hypocyst. Paraplate areas and crests are thick and microperforate and possess a spongy texture. The epicystal paratabulation is indiscernible but that of the hypocyst is clear and of the formula 6''', 1p.v., 1''''. The archeopyle is precingular, mid-dorsal in position.
Observed Dimensions: Holotype 35x32 Ám. Overall 36(34)29x35(31)29 Ám.
Emended diagnosis: Harding, 1986, p.19
Shape: Ambitus rectangular, elongated anteroposteriorly, maximum cyst width across posterior paracingular parasutural crest. Cyst length unequally divided, being 2/3 hypocyst, the remainder shared equally by the paracingulum and the epicyst. Little or no dorsoventral compression.
Phragma: Differentiated autophragm (Evitt, 1985, p. 64) in the manner of Aldorfia aldorfensis (see Gocht 1975), giving an alveolar appearance to the paraplate cross-section (Pl. 1, fig. 8). Total phragmal thickness 1.0-1.5 Ám. Autophragm outer surface perforate, pseudoreticulate. High parasutural crests developed on hypocyst up to 3 Ám high), much reduced on precingular paraplates to almost absent on the anterior intercalary and apical series.
Paratabulation: Pr, 4', 4a, 7", 7c, 6''', 1p, 1'''', 2s (Kofoidian notation. Taylor-Evitt plate equivalents as shown in Figs. 1, 2). Paraplates 7c[1i] and as [ai] narrow and elongate.
Archaeopyle: Variable. Types i., iii. or iv. as listed in the emended generic diagnosis.
Paracingulum: Strongly developed, delineated by high parasutural crest posteriorly, crest more subdued anteriorly.
Parasulcus: Prominent flagellar scar. Large spatulate sulcal paraplate s[Z], narrows rapidly towards para- cingulum. Paraplates rs[Ii] and Is[Im] not differentiated.
Affinities:
Duxbury, 1980, p. 117: The spongy body texture and crestal height variation (epicystal crests markedly higher than hypocystal ones) in D. jubatum distinguish it from all previously described species. D. apicopaucicum Habib, 1973 has a scabrate to microgranulate surface with some small variation in crestal height (see Habib, 1973, text-fig. 3). D. deflandrei (Millioud, 1969) Habib, 1973 and D. rhabdoreticulatum Habib, 1973 both display what appears to be a reticular pattern, with that of the former tending to be concentrated near parasutural lines. According to Habib (1973, p. 54), the membrane of D. rhabdoreticulatum is raised above the central tract and is supported by short baculae, imparting an angularity to the outline of the cysts". Such angularity is displayed by D. jubatum, but is due to the crestal height variation rather than to any obvious body layer separation.