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Kilwacysta multiramosa
Kilwacysta multiramosa Schrank, 2005, p.64,66, pl.7, figs.1–4.
Holotype: Schrank, 2005, pl.7, figs.1,3.
Age: Tithonian.
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Original description (Schrank, 2005):
Kilwacysta multiramosa sp. nov. Plate 7, figs. 1-4
Holotype. Gold-coated specimen on SEM stub no. AZG10, TUB catalogue number Pn 111, Plate 7, figs. 1,3.
Type locality. Tingutinguti section near Tendaguru, southeast Tansania.
Type stratum. Trigonia smeei Bed, at sample level Tin9p2.
Repository.Technische Universitat Berlin (TUB), Germany.
Derivation of name. Multi- (Latin for many), -ramosa (Latin for ramified).
Diagnosis. Skolochorate dinoflagellate cysts, central body ellipsoidal. Phragma laevigate, archeopyle apical. There are six process complexes in the precingular and probably five in the postcingular series. The larger processes may be fenestrate and arise from weakly defined, arcuate, septate ridges that may be foveolate and open towards the equatorial area.The processes of the dorsal side are wide, membraneous, strongly expanded distally and terminate into a series of irregular spines or in a spinose trabeculum. Those of the ventral side are more slender, solid, branched at one or more levels. The antapical complex is not prominent and consists of relatively thin, solid processes based on a low, annulate, septate ridge.
Description. Cysts are thin-walled and easily deformed. Maximum diameter of central body is about 50 to 60 % of total diameter. In lateral view, the process complexes appear to be concentrated around the two poles because of the absence of cingular processes. At the antapical pole, they are more densely packed than at the apical pole. In polar view, the cyst is dominated by large membraneous, multifurcate processes radiating outward. The minimum stem width of the large processes of the precingular series is about 4 µm at roughly one third of their length. From this level, they widen towards the base and even more so in a distal direction where they are curving outward, attaining a maximum width of up to c. 33 µm. They terminate distally with up to 10 spines of different sizes (length 1 to 9 µm) which may have bifid tips or form small digitate sub-complexes. Spinose trabeculae linking the distal parts of a process may be present. Stem width of the larger membraneous processes of the postcingular series is up to c. 8 urn close to the base. They expand distally and branch at successive levels up to four times. As a result a series of secondary complexes may be formed consisting of single spines or small bifid or digitate terminations. The more slender processes of the ventral side are bifurcate at one or two levels. They may also be trifurcate or show a combination of these features. The antapical process complex arises from a low, annulate, septate ridge (diameter c. 1 µm, minimum height of ridge c. 1 µm) and comprises a few relatively slender processes. These may be simple in the proximal part, but may show more complex spinose to digitate structures distally.
Dimensions. Holotype, a loisthocyst, central body 55 x 44 µm; total diameter 106 (width) x 79 µm. Maximum diameter of central body 41 (49) 60 µm, maximum total diameter 76 (92) 106 µm, 11 specimens measured in different orientations.
Discussion. Kilwacysta multiramosa is distinguished from Systematophora palmula Davey 1982 by the absence of a cingular process series, from Oligosphaeridium diliculum Davey 1982 by its membraneous, non-tubiform processes and from Kilwacysta semiseptata sp. nov. by its indistinct antapical process complex arising from a low annulate ridge. Present record.Trigonia smeei Bed (base Tin9j2, mainly Tin9p2).
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Holotype: Schrank, 2005, pl.7, figs.1,3.
Age: Tithonian.
-----------------------------------
Original description (Schrank, 2005):
Kilwacysta multiramosa sp. nov. Plate 7, figs. 1-4
Holotype. Gold-coated specimen on SEM stub no. AZG10, TUB catalogue number Pn 111, Plate 7, figs. 1,3.
Type locality. Tingutinguti section near Tendaguru, southeast Tansania.
Type stratum. Trigonia smeei Bed, at sample level Tin9p2.
Repository.Technische Universitat Berlin (TUB), Germany.
Derivation of name. Multi- (Latin for many), -ramosa (Latin for ramified).
Diagnosis. Skolochorate dinoflagellate cysts, central body ellipsoidal. Phragma laevigate, archeopyle apical. There are six process complexes in the precingular and probably five in the postcingular series. The larger processes may be fenestrate and arise from weakly defined, arcuate, septate ridges that may be foveolate and open towards the equatorial area.The processes of the dorsal side are wide, membraneous, strongly expanded distally and terminate into a series of irregular spines or in a spinose trabeculum. Those of the ventral side are more slender, solid, branched at one or more levels. The antapical complex is not prominent and consists of relatively thin, solid processes based on a low, annulate, septate ridge.
Description. Cysts are thin-walled and easily deformed. Maximum diameter of central body is about 50 to 60 % of total diameter. In lateral view, the process complexes appear to be concentrated around the two poles because of the absence of cingular processes. At the antapical pole, they are more densely packed than at the apical pole. In polar view, the cyst is dominated by large membraneous, multifurcate processes radiating outward. The minimum stem width of the large processes of the precingular series is about 4 µm at roughly one third of their length. From this level, they widen towards the base and even more so in a distal direction where they are curving outward, attaining a maximum width of up to c. 33 µm. They terminate distally with up to 10 spines of different sizes (length 1 to 9 µm) which may have bifid tips or form small digitate sub-complexes. Spinose trabeculae linking the distal parts of a process may be present. Stem width of the larger membraneous processes of the postcingular series is up to c. 8 urn close to the base. They expand distally and branch at successive levels up to four times. As a result a series of secondary complexes may be formed consisting of single spines or small bifid or digitate terminations. The more slender processes of the ventral side are bifurcate at one or two levels. They may also be trifurcate or show a combination of these features. The antapical process complex arises from a low, annulate, septate ridge (diameter c. 1 µm, minimum height of ridge c. 1 µm) and comprises a few relatively slender processes. These may be simple in the proximal part, but may show more complex spinose to digitate structures distally.
Dimensions. Holotype, a loisthocyst, central body 55 x 44 µm; total diameter 106 (width) x 79 µm. Maximum diameter of central body 41 (49) 60 µm, maximum total diameter 76 (92) 106 µm, 11 specimens measured in different orientations.
Discussion. Kilwacysta multiramosa is distinguished from Systematophora palmula Davey 1982 by the absence of a cingular process series, from Oligosphaeridium diliculum Davey 1982 by its membraneous, non-tubiform processes and from Kilwacysta semiseptata sp. nov. by its indistinct antapical process complex arising from a low annulate ridge. Present record.Trigonia smeei Bed (base Tin9j2, mainly Tin9p2).
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