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Damassadinium heterospinosum
Damassadinium heterospinosum (Matsuoka, 1983) Fensome et al., 1993
NOW Danea. Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Matsuoka, 1983, pl. pl.1, fig.1
Holotype. Slide no. NAG 33-1 (7uIII), sample NAG 33, Nanggulan Formation, Middle Eocene (CP 13 to CP 14 of Okada and Bukry, 1980). The type specimen is deposited in the palynologmal collection of the Department of Geology, Faculty of Liberal Arts, Nagasaki University. Locahty : River Kah Puru, Kalisongo near Nanggulan, about 20 km west of Yogjakarta, Central Java, Indonesia.
Age: Middle Eocene
Diagnosis: Proximochorate cyst with small bosses at both apex and antapex. Cyst large to mtermediate in size and composed of a thin, smooth endophragm and strongly fibrous periphragm. Processes of three different types: large penitabular, rectilinear and slender intratabular forms. Penitabular processes corresponded to the apical, precingular, postcingular and antapical paraplates, except for a few paraplates developed on the ventral surface. Apical processes 1' and 4' occasionally are different from the other apical processes in having a longitudinally expanded proximal base. Precingular 6" is usually indicated by reduced or incomplete penitabular, soleate to linear complexes or nearly intratabular processes. Postcingular paraplates 1'" and 2'" are also reduced and represented by smaller intratabular processes. Rectilinear processes with transversely expanded proximal bases occur in the cingulum. Slender intratabular processes are distributed in the sulcal area. The distal extremities of these slender processes are hystricate and occasionally strongly recurred. A precingular archeopyle with a rounded pentagonal margin is formed by loss of paraplate 3"; typically the operculum is detached completely. Paratabulation is 4', 6", 6c, 2-?5s, 6' ", lp and 1" ".
Derivation of name: Greek, hetero + spinosus = different + thorny, with reference to three different types of the processes.
Description: This spherical to subspherical cyst has a small boss at both apex and antapex (Plate I, lg; Plate II, la, 4). The cyst surface between the processes shows a strongly fibrous and reticulated structure (Plate II, 7b, 8). The large processes are penitabular and occasionally show incomplete box-like features where the walls of processes are reduced (Plate I, ld, e). In some specimens, these processes appear to be reduced to annular or soleate complexes, because of perforations and slits developed in the walls of the processes. Short slender spinous ornamentations are occasionally present within the paraplate field surrounded by the wall of a penitabular process (Plate II, 8 ). The apical processes are relatively smaller than the precingular, postcingular and antapical processes; nonetheless they are much larger than the slender intratabular sulcal processes. Apical paraplate 1' and 4' often are represented by penitabular processes with a longitudinally expanded proximal base. Paraplates 2' and 3' are sometimes indicated by large intratabular, rather than by penitabular, processes with proximal bases that are nearly circular m cross section. In the precingular series, process 6" is always smaller than the others and sometimes appears as an intratabular process or annulate to soleate complex. The postcingular series consists of four large penitabular processes, and two small, hollow and intratabular processes. Paraplate 1'" is always reduced, as is often observed in other gonyaulacacean cysts, and is represented by a slender and hollow intratabular process (Plate I, la) or by a soleate complex. Paraplate 2'" is also intratabular and smaller than the other postcingular processes. Paraplates 3' ", 4' ", 5'" and 6'" are large and distinctively penitabular. The posterior intercalary process (lp) is situated between the 1'" and the antapical processes, and resembles processes 1'" and 2' ". The antapical process is also penitabular and sometimes slightly larger than the others. The cingulum is represented by six rectilinear and membranous processes or linear complexes with transversely expanded proximal and distal ends, each probably occupying the centre of a paraplate (Plate I, lc; Plate II, lb, 3). The distal extremities of the rectilinear processes are denticulate to hystricate. Processes lc and 6c sometimes consist of a linear complex with two or three slender processes. The cingulum is slightly laevorotary and is displaced by its own width at the sulcus (Plate I, la; Fig.2A). The sulcus is indicated by at least five slender processes or reduced linear complex including the anterior sulcal process which always occupies the position between processes 1" and 6" and resembles processes 1' ", 2'" and lp in its variability of shape. The other sulcal processes are also variable in shape and even m number. Usually one slender process or a reduced linear complex occupies the positron between processes lp and 6' ". It probably reflects the posterior sulcal platelet. Two to three small and slender processes may be developed in the area surrounded by processes 1' ", lp, ps and 6' ", but they are not consistently present. These sulcal processes are smaller, more slender than the others and probably solid. The archeopyle is a simple precingular type, formed by displacement of 3" paraplate (Plate II, 5, 6). Dimensions: Holotype; length of central body 89.0 μm, breadth 84.6 μm, length of processes 23.5--26.5 μm, thickness of cyst wall ca. 1.2 μm. Other specimens; length of central body 66-102 μm, breadth 57-98 μm, length of processes 10--36 μm, thickness of cyst wall 0.8--1.2 μm. Number of specimens measured 52. Variation : The morphological variation of this species was observed to be as follows: (1) Cyst body shape: Most specimens are spherical to subspherical (Breadth/ Length of cyst body = 1.0--0.9), but slightly elongate forms (B/L = 0.9--0.8) are also encountered rarely (Plate II, la, 4). Small apical and antapical bosses are often developed (Plate I, lg; Plate II, la, 4), but a few specimens lack one or both. (2) Processes: The length of the processes is highly variable, from 10 μm to 36 μm, but is relatedly constant on any single specimen (Plate I, lb, 2b). The apical processes, especially processes 1' and 4', show some variation in their proximal bases. They vary from a quadrangular to a longitudinally rectangular shape. The wall of processes is also variable. Many penitabular processes have a relatively complete box-like proximal base and most of the rectilinear cingular processes show a completely membranous form. However, as a result of the fibrous structure becoming open, various perforations and slits are developed on the process walls (Plate I, ld, f). As a consequence these processes may appear to form sunulate, soleate or near complexes. The distribution of these reduced processes, most of which are 6" and 6c processes, is nearly limited to the ventral surface. Process 2'" is always smaller than the other postcingular processes except for process 1' ". A similar feature is reported in other species of Danea
Comparison with other related species: Danea heterospinosa sp. nov. is closely similar to D. californica (Drugg) Stover and Evitt in possessing fibrous penitabular paraplates and rectilinear cingular processes. However, it is distinguishable from the latter by the more spherical cyst body and by lacking conspicuous and flare-like apical horn constructed of thin fibrous periphragm usually with satelhtlc ridges and projections which were illustrated and described by Morgenroth (1968, pp.543--544, pl.43, 5--7) and Drugg (1970, p.816, figs.9F, 10A--F). Other species of Danea, D. impages Damassa 1979 and D. chibanis Below 1981, differ from the present species in possessing a distinctive apical horn and low penitabular ridges. This new species is also similar to Cordosphaeridium cf. biarmaturn described by Gocht (1969, pp.44--45; pl.III, 11; text-fig.30) in the following features: Based on the excellent illustrations and description given by Gocht, the latter form is similarly characterized by two or three different types of processes, including rectilinear cingular processes on the dorsal surface. However, it differs from this new species in being smaller, in having intratabular and occasionally membranous, rather than penitabular, processes and in lacking both apical and antapical bosses. Tityrosphaeridium ? biarmatum (Morgenroth 1966) Sarjeant 1981 is different from this new species in being smaller and in having mainly intratabular, rather than penitabular and rectilinear, processes. Danea heterospinosa also resembles Emmetrocysta ? fibrospinosa (Davey et Williams 1966) Sarjeant 1981 (= Cordosphaeridium fibrospinosum) in having two or three different types of processes and some taeniate cingular processes with transversely expanded proximal bases. This new species, however, differs in possessing a clearly precingular archeopyle, characteristically large penitabular processes, rectilinear cingular processes and small apical and antapical bosses. Cordosphaeridmm sp. 2, also reported by Gocht (1969, p.47; pl.III, 9, text-fig.33), resembles D. heterospinosa in possessing rectilinear dorsal cingular processes but differs in lacking penitabular processes. D heterospinosa is different from Muratodinium fimbriatum (Cookson et Eisenack 1967) Drugg 1970 in that it bears penitabular and intratabular processes rather than parasutural septa. Achilleodinium biformoides (Eisenack 1954) Eaton 1976 is also characterized by having two different types of intratabular processes, but differs from this new species in possessing a smooth or finely granular periphragm and in that its four apical processes are distinctively smaller than the precmgular, postcingular and antapical processes. Remarks: Danea heterospinosa provides us with a few important characters which clarify its phylogenetic relationships. This species and D. californica (Drugg) might be closely related to Achilleodmium and Tityrosphaendlum m having relatively high and distinctive penitabular and sometimes intratabular processes except for characteristic cingular processes and a fibrous periphragm. From viewpoints of the cyst shape and paraplate features, the existence of small bosses at both apex and antapex, and the relatively high and fibrous penitabular and rectilinear processes, one may suggest that this new species is closely related to Danea californica (Drugg). The latter species also has paraplate feature on the ventral surface sometimes reduced and different from those of the dorsal surface. This character is also occasionally paralleled by the reduced processes on the ventral surface in D heterospinosa. From a stratigraphical viewpoint, D californica (Drugg) has been obtained from the Paleocene (Danian) of North America (Damassa, 1979; Drugg, 1970) and Europe (Morgenroth, 1968). On the other hand, this new species has been found from the Middle Eocene of Central Java, Indonesia. Consequently the morphological affinity and the stratigraphical data strongly suggest that Danea californica (Drugg) might be the ancestor of D heterospinosa.
NOW Danea. Originally (and now) Danea, subsequently Damassadinium (generic name illegitimate).
Holotype: Matsuoka, 1983, pl. pl.1, fig.1
Holotype. Slide no. NAG 33-1 (7uIII), sample NAG 33, Nanggulan Formation, Middle Eocene (CP 13 to CP 14 of Okada and Bukry, 1980). The type specimen is deposited in the palynologmal collection of the Department of Geology, Faculty of Liberal Arts, Nagasaki University. Locahty : River Kah Puru, Kalisongo near Nanggulan, about 20 km west of Yogjakarta, Central Java, Indonesia.
Age: Middle Eocene
Diagnosis: Proximochorate cyst with small bosses at both apex and antapex. Cyst large to mtermediate in size and composed of a thin, smooth endophragm and strongly fibrous periphragm. Processes of three different types: large penitabular, rectilinear and slender intratabular forms. Penitabular processes corresponded to the apical, precingular, postcingular and antapical paraplates, except for a few paraplates developed on the ventral surface. Apical processes 1' and 4' occasionally are different from the other apical processes in having a longitudinally expanded proximal base. Precingular 6" is usually indicated by reduced or incomplete penitabular, soleate to linear complexes or nearly intratabular processes. Postcingular paraplates 1'" and 2'" are also reduced and represented by smaller intratabular processes. Rectilinear processes with transversely expanded proximal bases occur in the cingulum. Slender intratabular processes are distributed in the sulcal area. The distal extremities of these slender processes are hystricate and occasionally strongly recurred. A precingular archeopyle with a rounded pentagonal margin is formed by loss of paraplate 3"; typically the operculum is detached completely. Paratabulation is 4', 6", 6c, 2-?5s, 6' ", lp and 1" ".
Derivation of name: Greek, hetero + spinosus = different + thorny, with reference to three different types of the processes.
Description: This spherical to subspherical cyst has a small boss at both apex and antapex (Plate I, lg; Plate II, la, 4). The cyst surface between the processes shows a strongly fibrous and reticulated structure (Plate II, 7b, 8). The large processes are penitabular and occasionally show incomplete box-like features where the walls of processes are reduced (Plate I, ld, e). In some specimens, these processes appear to be reduced to annular or soleate complexes, because of perforations and slits developed in the walls of the processes. Short slender spinous ornamentations are occasionally present within the paraplate field surrounded by the wall of a penitabular process (Plate II, 8 ). The apical processes are relatively smaller than the precingular, postcingular and antapical processes; nonetheless they are much larger than the slender intratabular sulcal processes. Apical paraplate 1' and 4' often are represented by penitabular processes with a longitudinally expanded proximal base. Paraplates 2' and 3' are sometimes indicated by large intratabular, rather than by penitabular, processes with proximal bases that are nearly circular m cross section. In the precingular series, process 6" is always smaller than the others and sometimes appears as an intratabular process or annulate to soleate complex. The postcingular series consists of four large penitabular processes, and two small, hollow and intratabular processes. Paraplate 1'" is always reduced, as is often observed in other gonyaulacacean cysts, and is represented by a slender and hollow intratabular process (Plate I, la) or by a soleate complex. Paraplate 2'" is also intratabular and smaller than the other postcingular processes. Paraplates 3' ", 4' ", 5'" and 6'" are large and distinctively penitabular. The posterior intercalary process (lp) is situated between the 1'" and the antapical processes, and resembles processes 1'" and 2' ". The antapical process is also penitabular and sometimes slightly larger than the others. The cingulum is represented by six rectilinear and membranous processes or linear complexes with transversely expanded proximal and distal ends, each probably occupying the centre of a paraplate (Plate I, lc; Plate II, lb, 3). The distal extremities of the rectilinear processes are denticulate to hystricate. Processes lc and 6c sometimes consist of a linear complex with two or three slender processes. The cingulum is slightly laevorotary and is displaced by its own width at the sulcus (Plate I, la; Fig.2A). The sulcus is indicated by at least five slender processes or reduced linear complex including the anterior sulcal process which always occupies the position between processes 1" and 6" and resembles processes 1' ", 2'" and lp in its variability of shape. The other sulcal processes are also variable in shape and even m number. Usually one slender process or a reduced linear complex occupies the positron between processes lp and 6' ". It probably reflects the posterior sulcal platelet. Two to three small and slender processes may be developed in the area surrounded by processes 1' ", lp, ps and 6' ", but they are not consistently present. These sulcal processes are smaller, more slender than the others and probably solid. The archeopyle is a simple precingular type, formed by displacement of 3" paraplate (Plate II, 5, 6). Dimensions: Holotype; length of central body 89.0 μm, breadth 84.6 μm, length of processes 23.5--26.5 μm, thickness of cyst wall ca. 1.2 μm. Other specimens; length of central body 66-102 μm, breadth 57-98 μm, length of processes 10--36 μm, thickness of cyst wall 0.8--1.2 μm. Number of specimens measured 52. Variation : The morphological variation of this species was observed to be as follows: (1) Cyst body shape: Most specimens are spherical to subspherical (Breadth/ Length of cyst body = 1.0--0.9), but slightly elongate forms (B/L = 0.9--0.8) are also encountered rarely (Plate II, la, 4). Small apical and antapical bosses are often developed (Plate I, lg; Plate II, la, 4), but a few specimens lack one or both. (2) Processes: The length of the processes is highly variable, from 10 μm to 36 μm, but is relatedly constant on any single specimen (Plate I, lb, 2b). The apical processes, especially processes 1' and 4', show some variation in their proximal bases. They vary from a quadrangular to a longitudinally rectangular shape. The wall of processes is also variable. Many penitabular processes have a relatively complete box-like proximal base and most of the rectilinear cingular processes show a completely membranous form. However, as a result of the fibrous structure becoming open, various perforations and slits are developed on the process walls (Plate I, ld, f). As a consequence these processes may appear to form sunulate, soleate or near complexes. The distribution of these reduced processes, most of which are 6" and 6c processes, is nearly limited to the ventral surface. Process 2'" is always smaller than the other postcingular processes except for process 1' ". A similar feature is reported in other species of Danea
Comparison with other related species: Danea heterospinosa sp. nov. is closely similar to D. californica (Drugg) Stover and Evitt in possessing fibrous penitabular paraplates and rectilinear cingular processes. However, it is distinguishable from the latter by the more spherical cyst body and by lacking conspicuous and flare-like apical horn constructed of thin fibrous periphragm usually with satelhtlc ridges and projections which were illustrated and described by Morgenroth (1968, pp.543--544, pl.43, 5--7) and Drugg (1970, p.816, figs.9F, 10A--F). Other species of Danea, D. impages Damassa 1979 and D. chibanis Below 1981, differ from the present species in possessing a distinctive apical horn and low penitabular ridges. This new species is also similar to Cordosphaeridium cf. biarmaturn described by Gocht (1969, pp.44--45; pl.III, 11; text-fig.30) in the following features: Based on the excellent illustrations and description given by Gocht, the latter form is similarly characterized by two or three different types of processes, including rectilinear cingular processes on the dorsal surface. However, it differs from this new species in being smaller, in having intratabular and occasionally membranous, rather than penitabular, processes and in lacking both apical and antapical bosses. Tityrosphaeridium ? biarmatum (Morgenroth 1966) Sarjeant 1981 is different from this new species in being smaller and in having mainly intratabular, rather than penitabular and rectilinear, processes. Danea heterospinosa also resembles Emmetrocysta ? fibrospinosa (Davey et Williams 1966) Sarjeant 1981 (= Cordosphaeridium fibrospinosum) in having two or three different types of processes and some taeniate cingular processes with transversely expanded proximal bases. This new species, however, differs in possessing a clearly precingular archeopyle, characteristically large penitabular processes, rectilinear cingular processes and small apical and antapical bosses. Cordosphaeridmm sp. 2, also reported by Gocht (1969, p.47; pl.III, 9, text-fig.33), resembles D. heterospinosa in possessing rectilinear dorsal cingular processes but differs in lacking penitabular processes. D heterospinosa is different from Muratodinium fimbriatum (Cookson et Eisenack 1967) Drugg 1970 in that it bears penitabular and intratabular processes rather than parasutural septa. Achilleodinium biformoides (Eisenack 1954) Eaton 1976 is also characterized by having two different types of intratabular processes, but differs from this new species in possessing a smooth or finely granular periphragm and in that its four apical processes are distinctively smaller than the precmgular, postcingular and antapical processes. Remarks: Danea heterospinosa provides us with a few important characters which clarify its phylogenetic relationships. This species and D. californica (Drugg) might be closely related to Achilleodmium and Tityrosphaendlum m having relatively high and distinctive penitabular and sometimes intratabular processes except for characteristic cingular processes and a fibrous periphragm. From viewpoints of the cyst shape and paraplate features, the existence of small bosses at both apex and antapex, and the relatively high and fibrous penitabular and rectilinear processes, one may suggest that this new species is closely related to Danea californica (Drugg). The latter species also has paraplate feature on the ventral surface sometimes reduced and different from those of the dorsal surface. This character is also occasionally paralleled by the reduced processes on the ventral surface in D heterospinosa. From a stratigraphical viewpoint, D californica (Drugg) has been obtained from the Paleocene (Danian) of North America (Damassa, 1979; Drugg, 1970) and Europe (Morgenroth, 1968). On the other hand, this new species has been found from the Middle Eocene of Central Java, Indonesia. Consequently the morphological affinity and the stratigraphical data strongly suggest that Danea californica (Drugg) might be the ancestor of D heterospinosa.