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Damassadinium impages
Damassadinium impages (Damassa, 1979) Femsome et al., 1993
NOW Danea. Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Damassa, 1979, pl.1, fig.1-2
Paratypes: Damassa, 1979
Locus typicus: Coastal Belt, Franciscan Complex, Califonia, USA
Stratum typicum: Early-Middle Eocene
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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.
Damassadinium impages (Damassa, 1979c) Fensome et al., 1993b, is proximate, spherical to ellipsoidal, with a fibrous surface. Paratabulation indicated by low, perforate, penitabular ridges on the large paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Precingular archeopyle with rounded pentagonal margin. Small horn commonly developed at apex and antapex. Size: length 82-101 µm, width 66-77 µm. Wall thickness 1-2 µm. Ridges 3-6 µm high.
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Original diagnosis: Damassa, 1979, p. 321 (Danea impages):
Proximate cyst, spherical to ellipsoidal in shape; surface of cyst fibrous. Paratabulation indicated by low perforate penitabular ridges on the larger paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Precingular archeopyle with rounded pentagonal margin. Small horn commonly developed at apex and antapex.
Original description: Damassa, 1979, p. 321-322 (Danea impages):
Proximate cyst, spherical to ellipsoidal in shape. Wall consisting of autophragm only. Length 82-101 µm width 66 µm; holotype 101 µm x 66 µm; three specimens measured. Single horns generally present at apex and antapex, more or less conical in shape, formed by protrusion of the wall. Wall 1-2 Ám in thickness. Paratabulation indicated by low perforate penitabular ridges, 3-6 m in height on the larger paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Surface of cyst fibrous, weblike in appearance, becoming smoother and more nearly solid in the parasulcal region. Precingular archeopyle. Type P, formed by loss of the third precingular paraplate. Archeopyle may be enlarged. Operculum free, with a rounded pentagonal outline.
Paratabulation. 4', 6", 6c, 4-5s, 1p, 6''', 1''''. Inferred thecal tabulation. 4', 6", 6c, 5s, 1p, 6''', 1''''.
Affinities:
Damassa, 1979, p. 822 (Danea impages): Danea impages differs from D. californica (Drugg) in having low ridges rather than high septa, but both have a penitabular gonyaulacacean paratabulation (Text-fig. 3). The parasulcal region of D. impages (like D. californica) is characterized by a reduction in the size of the paraplates. The sixth precingular paraplate is represented soleIy by an extremely short ridge which resembles those of the small sulcal paraplates. The area defined by the second postcingular penitabular ridge commonly is oval to subtriangular in outline (Pl. 1, fig. 1; Pl. 2, fig. 1). Ridges which correspond to paraplates 1p and ps are arcuate. The cingular paraplates are represented by a series of six rectilinear ridges which are located at the center of the paracingulum; thus the cingular paratabulation is essentially intratabular rather tnan penitabular. The ends of the paracingulum are offset by a distance about equal to the inferred width of the cingulum. Ridges on the first and fourth apical paraplates are variable in development: both may have complete penitabular ridges (PI. 2, fig. 2), both may be indicated by two rectilinear ridges similar to those of the parasulcus and paracingulum (Pl. 1. figs. 1, 2) or by a combination of a complete penitabular ridge and a rectilinear ridge (PI. 2, fig. 6).
As the formation of the archeopyle may result in the removal of fragments of adjacent penitabular ridges, such as those of 2", 4", 2', 3'. the archeopyle may be slightly enlarged (PI. 2, figs. 2). The ridges which represent the apical, precingular, postcingular and antapical paraplates tend to have rounded corners, but in general the outlines follow those of typical gonyaulacacean plate boundaries. The penitabular ridges are formed as eleations of the wall (PI. 2, fig. 8), and are irregularly perforated with rounded openings of various sizes.
NOW Danea. Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Damassa, 1979, pl.1, fig.1-2
Paratypes: Damassa, 1979
Locus typicus: Coastal Belt, Franciscan Complex, Califonia, USA
Stratum typicum: Early-Middle Eocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Damassadinium impages (Damassa, 1979c) Fensome et al., 1993b, is proximate, spherical to ellipsoidal, with a fibrous surface. Paratabulation indicated by low, perforate, penitabular ridges on the large paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Precingular archeopyle with rounded pentagonal margin. Small horn commonly developed at apex and antapex. Size: length 82-101 µm, width 66-77 µm. Wall thickness 1-2 µm. Ridges 3-6 µm high.
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Original diagnosis: Damassa, 1979, p. 321 (Danea impages):
Proximate cyst, spherical to ellipsoidal in shape; surface of cyst fibrous. Paratabulation indicated by low perforate penitabular ridges on the larger paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Precingular archeopyle with rounded pentagonal margin. Small horn commonly developed at apex and antapex.
Original description: Damassa, 1979, p. 321-322 (Danea impages):
Proximate cyst, spherical to ellipsoidal in shape. Wall consisting of autophragm only. Length 82-101 µm width 66 µm; holotype 101 µm x 66 µm; three specimens measured. Single horns generally present at apex and antapex, more or less conical in shape, formed by protrusion of the wall. Wall 1-2 Ám in thickness. Paratabulation indicated by low perforate penitabular ridges, 3-6 m in height on the larger paraplates. Sulcal, cingular and posterior intercalary paraplates indicated by rectilinear or arcuate ridges. Apical paraplates 1' and 4' may be represented as rectilinear ridges or as complete penitabular ridges. Surface of cyst fibrous, weblike in appearance, becoming smoother and more nearly solid in the parasulcal region. Precingular archeopyle. Type P, formed by loss of the third precingular paraplate. Archeopyle may be enlarged. Operculum free, with a rounded pentagonal outline.
Paratabulation. 4', 6", 6c, 4-5s, 1p, 6''', 1''''. Inferred thecal tabulation. 4', 6", 6c, 5s, 1p, 6''', 1''''.
Affinities:
Damassa, 1979, p. 822 (Danea impages): Danea impages differs from D. californica (Drugg) in having low ridges rather than high septa, but both have a penitabular gonyaulacacean paratabulation (Text-fig. 3). The parasulcal region of D. impages (like D. californica) is characterized by a reduction in the size of the paraplates. The sixth precingular paraplate is represented soleIy by an extremely short ridge which resembles those of the small sulcal paraplates. The area defined by the second postcingular penitabular ridge commonly is oval to subtriangular in outline (Pl. 1, fig. 1; Pl. 2, fig. 1). Ridges which correspond to paraplates 1p and ps are arcuate. The cingular paraplates are represented by a series of six rectilinear ridges which are located at the center of the paracingulum; thus the cingular paratabulation is essentially intratabular rather tnan penitabular. The ends of the paracingulum are offset by a distance about equal to the inferred width of the cingulum. Ridges on the first and fourth apical paraplates are variable in development: both may have complete penitabular ridges (PI. 2, fig. 2), both may be indicated by two rectilinear ridges similar to those of the parasulcus and paracingulum (Pl. 1. figs. 1, 2) or by a combination of a complete penitabular ridge and a rectilinear ridge (PI. 2, fig. 6).
As the formation of the archeopyle may result in the removal of fragments of adjacent penitabular ridges, such as those of 2", 4", 2', 3'. the archeopyle may be slightly enlarged (PI. 2, figs. 2). The ridges which represent the apical, precingular, postcingular and antapical paraplates tend to have rounded corners, but in general the outlines follow those of typical gonyaulacacean plate boundaries. The penitabular ridges are formed as eleations of the wall (PI. 2, fig. 8), and are irregularly perforated with rounded openings of various sizes.