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Phthanoperidinium filigranum
Phthanoperidinium filigranum (Benedek, 1972) Benedek and Sarjeant, 1981
Originally Deflandrea?, subsequently Vozzhennikovia?, thirdly Dioxya, fourthly (and now) Phthanoperidinium. The transfer of this species to Phthanoperidinium is not attributable to Bujak and Davies, 1983.
Holotype: Benedek, 1972, pl.4, fig.3a-b; Benedek and Sarjeant, 1981, figs.4,8, nos.1-2
Locus typicus: Tönisberg, Lower Rhine Embayment, Germany
Stratum typicum: Middle Oligocene
Translation Benedek, 1972: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Phthanoperidinium filigranum (Benedek, 1972) Benedek and Sarjeant, 1981. According to Benedek and Sarjeant (1981): Cyst proximate, cornucavate, broadly spindle-shaped in ambitus and with short apical and antapical horns. Epitract and hypotract equal in size. Low crests outline the following tabulation 4', ?3a, 7", 6c, 5"’, 1p, 1pv, 2"”. Paracingulum broad, only slightly laevorotatory: parasulcus only moderately broad. Surface of periphragm covered by a net-like, fine-meshed ornament, reduced in the mid-ventral region. Archeopyle intercalary, formed by the loss of a single paraplate (type I): archeopyle index less than 0.5; operculum free. Size: overall length 40-45 µm, width 43-45 µm, length of apical horn 2.5-3 µm, length of antapical horn similar.
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Original diagnosis: Benedek, 1972, p.12: ?Deflandrea filigrana
A species of the genus ?Deflandrea with one antapical horn. The thin-walled, granular capsule is circular. Trapezoid pylome developed below the apex.
Original description: Benedek, 1972, p.13: ?Deflandrea filigrana
Capsule circular to elliptical with transparent, brownish surface. The smooth, thin-walled inner capusle is of ellipsoidal outline. Outer membrane closely appressed to inner membrane and densely covered by numerous irregular spines. Transverse furrow relatively wide and ventrally bordered by low ridges, which turn into the longitudinal furrow of the hypotheca. Tabulation not indicated. Apical horn short and pointed. Antapical horn weakly developed. Trapezodal pylome developed below the apex.
Dimensions: Capsule length 40-45 µm, breadth 43-45 µm, apical horn 2.5-3 µm (10 specimens).
Supplemental diagnosis: Benedek and Sarjeant, 1981, p.325
Cyst proximate, cornucavate, broadly spindleshaped in ambitus and with short apical and antapical horns. Epitract and hypotract equal in size. Low crests outline the following paratabulation: 4', ?3a, 7", 6c, 5''', 1p, 1pv, 2''''. Paracingulum broad only slightly laevorotatory: parasulcus only moderately broad. Surface of periphragm covered by a net-like, fine-meshed ornament, reduced in the mid-ventral region. Archaeopyle intercalary, formed by the loss of a single paraplate (type 1): archaeopyle index less than 0.5 operculum free.
Supplemental description: Benedek and Sarjeant, 1981, p.326-327
The cyst has a two-layered phragma, the wall layers separating only at apex and antapex where short, rounded mamelon-like horns are developed. Sutures between paraplates bea; low crests of simple character, defining a peridinoid tabulation. Of the four apical paraplates, 1' is elongate and occupies the anterior prolongation of the parasulcus; 2' is the largest of the series, 3' and 4' being much smaller. It is presumed that three anterior intercalary paraplates are present, but neither 1a nor 3a could be clearly determined in the specimens examined. The paraplate here provisionally designated 2a accords with the "standard hexa" type of Lentin and Williams ( 1975) it is consistently lost in archaeopyle formation.
Paraplate 1'' is the smallest of the precingulars and almost square in shape; paraplate 4'''' is short but broad. Six cingular paraplates are present, 1c and 6c being the smallest of the series and placed almost symmetrically on the ventral surface, the paracingulum being only slightly laevorotatory. (Its two ends scarcely differ in anteroposterior position). Paraplates 1''' and 2''' are reduced to accommodate a posterior intercalary paraplate of proportionately large size; paraplate 5''' is also relatively small. Three paraplates occupy the antapex: all three might justly be designated as antapicals but, in accordance with the convention for this genus, the paraplate posterior to the parasulcus is here distinguished as posterior ventral (1pv).
A netlike ornament covers much of the surface, though it may be lacking from the central area of the parasulcus and recuced on the paracingulum. The meshes, though always fine, are coarsest at the centres of paraplates and become elongate at margins where growth occurred on the motile theca (see Fig. 4, inset).
Dimensions: Holotype - length 43 µm, breadth 34 µm, length of apical horn 3 µm length of antapical horn c. 2.5 µm. Range of dimensions: length 40-45 µm, breadth 43-45 µm, length of apical horn 2.5-3 µm, length of antapical horn similar. Material: 32 specimens.
Affinities:
Benedek and Sarjeant, 1981, p. 327: Of other species hitherto described, the most similar is perhaps Phthanoperidinium eocenicum (Cookson and Eisenack, 1965) Lentin and Williams, 1973, a species whose detailed paratabulation has not yet been determined. Whilst its "solid horns" may be perhaps discounted, this species also differs from P. filigranum in having dot-like thickenings on paraplate surfaces, instead of a netlike ornament, and in its somewhat more elongate shape. Phthanoperidinium resistente (Morgenroth, 1966) Lentin and Williams, 1973, considered by Stover and Evitt (1978) to be possibly conspecific with P. eocenicum, differs from P. filigranum in having a smooth surface and strongly granulate paraplate boundaries: its apical horn is also markedly longer.
Originally Deflandrea?, subsequently Vozzhennikovia?, thirdly Dioxya, fourthly (and now) Phthanoperidinium. The transfer of this species to Phthanoperidinium is not attributable to Bujak and Davies, 1983.
Holotype: Benedek, 1972, pl.4, fig.3a-b; Benedek and Sarjeant, 1981, figs.4,8, nos.1-2
Locus typicus: Tönisberg, Lower Rhine Embayment, Germany
Stratum typicum: Middle Oligocene
Translation Benedek, 1972: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Phthanoperidinium filigranum (Benedek, 1972) Benedek and Sarjeant, 1981. According to Benedek and Sarjeant (1981): Cyst proximate, cornucavate, broadly spindle-shaped in ambitus and with short apical and antapical horns. Epitract and hypotract equal in size. Low crests outline the following tabulation 4', ?3a, 7", 6c, 5"’, 1p, 1pv, 2"”. Paracingulum broad, only slightly laevorotatory: parasulcus only moderately broad. Surface of periphragm covered by a net-like, fine-meshed ornament, reduced in the mid-ventral region. Archeopyle intercalary, formed by the loss of a single paraplate (type I): archeopyle index less than 0.5; operculum free. Size: overall length 40-45 µm, width 43-45 µm, length of apical horn 2.5-3 µm, length of antapical horn similar.
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Original diagnosis: Benedek, 1972, p.12: ?Deflandrea filigrana
A species of the genus ?Deflandrea with one antapical horn. The thin-walled, granular capsule is circular. Trapezoid pylome developed below the apex.
Original description: Benedek, 1972, p.13: ?Deflandrea filigrana
Capsule circular to elliptical with transparent, brownish surface. The smooth, thin-walled inner capusle is of ellipsoidal outline. Outer membrane closely appressed to inner membrane and densely covered by numerous irregular spines. Transverse furrow relatively wide and ventrally bordered by low ridges, which turn into the longitudinal furrow of the hypotheca. Tabulation not indicated. Apical horn short and pointed. Antapical horn weakly developed. Trapezodal pylome developed below the apex.
Dimensions: Capsule length 40-45 µm, breadth 43-45 µm, apical horn 2.5-3 µm (10 specimens).
Supplemental diagnosis: Benedek and Sarjeant, 1981, p.325
Cyst proximate, cornucavate, broadly spindleshaped in ambitus and with short apical and antapical horns. Epitract and hypotract equal in size. Low crests outline the following paratabulation: 4', ?3a, 7", 6c, 5''', 1p, 1pv, 2''''. Paracingulum broad only slightly laevorotatory: parasulcus only moderately broad. Surface of periphragm covered by a net-like, fine-meshed ornament, reduced in the mid-ventral region. Archaeopyle intercalary, formed by the loss of a single paraplate (type 1): archaeopyle index less than 0.5 operculum free.
Supplemental description: Benedek and Sarjeant, 1981, p.326-327
The cyst has a two-layered phragma, the wall layers separating only at apex and antapex where short, rounded mamelon-like horns are developed. Sutures between paraplates bea; low crests of simple character, defining a peridinoid tabulation. Of the four apical paraplates, 1' is elongate and occupies the anterior prolongation of the parasulcus; 2' is the largest of the series, 3' and 4' being much smaller. It is presumed that three anterior intercalary paraplates are present, but neither 1a nor 3a could be clearly determined in the specimens examined. The paraplate here provisionally designated 2a accords with the "standard hexa" type of Lentin and Williams ( 1975) it is consistently lost in archaeopyle formation.
Paraplate 1'' is the smallest of the precingulars and almost square in shape; paraplate 4'''' is short but broad. Six cingular paraplates are present, 1c and 6c being the smallest of the series and placed almost symmetrically on the ventral surface, the paracingulum being only slightly laevorotatory. (Its two ends scarcely differ in anteroposterior position). Paraplates 1''' and 2''' are reduced to accommodate a posterior intercalary paraplate of proportionately large size; paraplate 5''' is also relatively small. Three paraplates occupy the antapex: all three might justly be designated as antapicals but, in accordance with the convention for this genus, the paraplate posterior to the parasulcus is here distinguished as posterior ventral (1pv).
A netlike ornament covers much of the surface, though it may be lacking from the central area of the parasulcus and recuced on the paracingulum. The meshes, though always fine, are coarsest at the centres of paraplates and become elongate at margins where growth occurred on the motile theca (see Fig. 4, inset).
Dimensions: Holotype - length 43 µm, breadth 34 µm, length of apical horn 3 µm length of antapical horn c. 2.5 µm. Range of dimensions: length 40-45 µm, breadth 43-45 µm, length of apical horn 2.5-3 µm, length of antapical horn similar. Material: 32 specimens.
Affinities:
Benedek and Sarjeant, 1981, p. 327: Of other species hitherto described, the most similar is perhaps Phthanoperidinium eocenicum (Cookson and Eisenack, 1965) Lentin and Williams, 1973, a species whose detailed paratabulation has not yet been determined. Whilst its "solid horns" may be perhaps discounted, this species also differs from P. filigranum in having dot-like thickenings on paraplate surfaces, instead of a netlike ornament, and in its somewhat more elongate shape. Phthanoperidinium resistente (Morgenroth, 1966) Lentin and Williams, 1973, considered by Stover and Evitt (1978) to be possibly conspecific with P. eocenicum, differs from P. filigranum in having a smooth surface and strongly granulate paraplate boundaries: its apical horn is also markedly longer.