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Danea abbreviata
Danea abbreviata Damassa, 1984
Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Damassa, 1984. pl.1, fig.1-6
Locus typicus: N California, USA
Stratum typicum: Eocene
Original diagnosis: Damassa, 1984, p. 54
Proximate cyst, ellipsoidal in shape. Wall consisting of autophragm only; surface of wall fibrous to rugulate in appearance. Gonyaulacacean paratabulation indicated by penitabular and intratabular septa or ridges of low relief. Apical paraplates characterized by penitabular septa which may grade into short intratabular processes. Cingular paraplates represented by discontinuous intratabular ridges which form a shelf-like structure; sulcal paraplates defined by intratabular processes or arcuate ridges. Large pre- and postcingular paraplates defined by incomplete penitabular septa: i.e., septa are undeveloped along adcingular paraplate boundaries. Antapical septum penitabular, complete. Archeopyle Type P (3").
Original description: Damassa, 1984, p. 54
Proximate cyst, ellipsoidal in shape, wall consisting of autophragm only. Length of autocyst 75 Ám, width 65-67 Ám; holotype 75 x 67 Ám. Surface of cyst fibrous to rugulate in appearance. Small horn may be present at apex and antapex, formed by slight protrusion of the autophragm. Wall approximately 2 Ám in thickness. Gonyaulacacean paratabulation indicated by penitabular and intratabular septa or ridges of low relief, 5-10 Ám in height. Apical paraplates delineated by penitabular septa which may grade into short intratabular processes (Plate 3, figs. 2, 3).
Cingular paraplates represented by discontinuous rectilinear intratabular septa which may coalesce to form a shelf-like structure on the dorsal surface immediately posterior to the archeopyle (Plate 1, fig. I; Plate 3, fig. 2). Sulcal paraplates defined by intratabular processes or arcuate ridges. Ends of paracingulum offset a distance approximately equal to the inferred width of the cingulum. Large pre- and postcingular paraplates (1"-5", 3"""-6""") represented by incompletely developed penitabular septa: i.e., septa are undeveloped along adcingular margins of paraplates. Antapical paraplate delineated by complete penitabular septum. Paraplates adjacent to the sulcus, i.e., 6", 1""", 2""", 1p, notably small in size; delineated by intratabular processes or arcuate ridges. Precingular archeopyle, Type P, formed by loss of third precingular paraplate. Archeopyle margin rounded and slightly enlarged; operculum free, not observed.
Paratabulation. 4", 6", 6c, 4-5s, 6""", 1p, 1"""". Inferred thecal tabulation. 4", 6", 6c, 5s, 6""", 1p, 1"""".
Affinities:
Damassa, 1984, p. 54-55: The enlargement of the archeopyle may be inferred from the proximity of the subjacent paracingular septa to the posterior margin of the archeopyle. As the cingular paraplates are represented by shelf-like intratabular septa (presumably located in a medial position on those paraplates), it would seem that the operculum would thus include a portion of the cingular paraplates. A similar observation was made with respect to the archeopyle in D. impages (Damassa, 1979a, p. 822). D. abbreviata most closely resembles D. manicata n. sp., but the two may be distinguished by the difference in the height of their septa and processes (5-10 Ám vs. 13-26 Ám). In addition, the wall texture observed in D. abbreviata is less fibrous than that of D. manicata. D. abbreviata may be distinguished from D. chibanis (Below 1981) and D. impages (Damassa 1979), which also have septa and ridges of low relief, by the incomplete vs. complete development of the penitabular septa on the large pre- and postcingular paraplates. The relative dimensions of D. impages and D. abbreviata also provide a basis for distinction. For the former, the length of the autocyst is 82- 101 Ám, ridges 3-6 Ám in height; for the latter the autocyst is only about 75 Ám long, while septa are 5- 10 Ám high. Although the number of specimens upon which this description is based is small, some degree of intraspecific variability was observed with respect to the pre- and postcingular septa. Some individuals show a slight tendency toward more complete development of the penitabular septa; in addition, the apical paraplates may display either penitabular septa or intratabular processes.
Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Damassa, 1984. pl.1, fig.1-6
Locus typicus: N California, USA
Stratum typicum: Eocene
Original diagnosis: Damassa, 1984, p. 54
Proximate cyst, ellipsoidal in shape. Wall consisting of autophragm only; surface of wall fibrous to rugulate in appearance. Gonyaulacacean paratabulation indicated by penitabular and intratabular septa or ridges of low relief. Apical paraplates characterized by penitabular septa which may grade into short intratabular processes. Cingular paraplates represented by discontinuous intratabular ridges which form a shelf-like structure; sulcal paraplates defined by intratabular processes or arcuate ridges. Large pre- and postcingular paraplates defined by incomplete penitabular septa: i.e., septa are undeveloped along adcingular paraplate boundaries. Antapical septum penitabular, complete. Archeopyle Type P (3").
Original description: Damassa, 1984, p. 54
Proximate cyst, ellipsoidal in shape, wall consisting of autophragm only. Length of autocyst 75 Ám, width 65-67 Ám; holotype 75 x 67 Ám. Surface of cyst fibrous to rugulate in appearance. Small horn may be present at apex and antapex, formed by slight protrusion of the autophragm. Wall approximately 2 Ám in thickness. Gonyaulacacean paratabulation indicated by penitabular and intratabular septa or ridges of low relief, 5-10 Ám in height. Apical paraplates delineated by penitabular septa which may grade into short intratabular processes (Plate 3, figs. 2, 3).
Cingular paraplates represented by discontinuous rectilinear intratabular septa which may coalesce to form a shelf-like structure on the dorsal surface immediately posterior to the archeopyle (Plate 1, fig. I; Plate 3, fig. 2). Sulcal paraplates defined by intratabular processes or arcuate ridges. Ends of paracingulum offset a distance approximately equal to the inferred width of the cingulum. Large pre- and postcingular paraplates (1"-5", 3"""-6""") represented by incompletely developed penitabular septa: i.e., septa are undeveloped along adcingular margins of paraplates. Antapical paraplate delineated by complete penitabular septum. Paraplates adjacent to the sulcus, i.e., 6", 1""", 2""", 1p, notably small in size; delineated by intratabular processes or arcuate ridges. Precingular archeopyle, Type P, formed by loss of third precingular paraplate. Archeopyle margin rounded and slightly enlarged; operculum free, not observed.
Paratabulation. 4", 6", 6c, 4-5s, 6""", 1p, 1"""". Inferred thecal tabulation. 4", 6", 6c, 5s, 6""", 1p, 1"""".
Affinities:
Damassa, 1984, p. 54-55: The enlargement of the archeopyle may be inferred from the proximity of the subjacent paracingular septa to the posterior margin of the archeopyle. As the cingular paraplates are represented by shelf-like intratabular septa (presumably located in a medial position on those paraplates), it would seem that the operculum would thus include a portion of the cingular paraplates. A similar observation was made with respect to the archeopyle in D. impages (Damassa, 1979a, p. 822). D. abbreviata most closely resembles D. manicata n. sp., but the two may be distinguished by the difference in the height of their septa and processes (5-10 Ám vs. 13-26 Ám). In addition, the wall texture observed in D. abbreviata is less fibrous than that of D. manicata. D. abbreviata may be distinguished from D. chibanis (Below 1981) and D. impages (Damassa 1979), which also have septa and ridges of low relief, by the incomplete vs. complete development of the penitabular septa on the large pre- and postcingular paraplates. The relative dimensions of D. impages and D. abbreviata also provide a basis for distinction. For the former, the length of the autocyst is 82- 101 Ám, ridges 3-6 Ám in height; for the latter the autocyst is only about 75 Ám long, while septa are 5- 10 Ám high. Although the number of specimens upon which this description is based is small, some degree of intraspecific variability was observed with respect to the pre- and postcingular septa. Some individuals show a slight tendency toward more complete development of the penitabular septa; in addition, the apical paraplates may display either penitabular septa or intratabular processes.