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Lithodinia arcanitabulata
Lithodinia arcanitabulata Brenner, 1988
Holotype: Brenner, 1988, pl.18, fig.4
Age: Oxfordian-Early Kimmeridgian
Stratum typicum: Upper Jurassic, lower Malm gamma, platynota Zone (lower Kimmeridgian)
Locus typicus: Hörnlebruch near Neuffen, Germany
Translation Brenner 1988: LPP
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Brenner 1988, p. 61-63, pl.18, fig.3-5
Diagnosis: Oval to polygonal dinoflagellate cyst with apical archaeopyle and a triple-layered main cyst wall, which consist of a thin "inner membrane", a coarsely porate to cavernous "main cyst wall" and a thin "outer membrane". In transmitted light the parasulcus is recognizeable as a by the clear reduction of thickness of the main cyst wall. The paracingulum is indicated, the paratabulation cannot be recognized. In SEM, the paraplate margins are clearly indicated.
Dimensions of holotype: length 54 µm, width 68 µm, cyst wall 3-6 µm.
Description:
Dinoflagellate cyst with ovoidal to polygonal appearance and gonyaulacoidal paratabulation. The archaeopyle is apical type 4A, the operculum tetra-otho (sensu Wille, 1985). In the total material studied, no single operculum of the decribed species was encountered, which points to a separation of the apical plates. The cyst diameter cyst is 55-70 µm. The wall thickness wall is 3-6 µm; it consists of a smooth, 0.1 µm thick "inner membrane", a foamy to cavernous "main cyst wall", as it is similarly present in Aldorfia aldorfensis and Eodinia pachytheca (cf. Gocht 1975a and 1975b), and a porous "outer membrane" which is also 0.1 µm thick.
In transmitted light, the paracingulum is hard to recognize, the parasulcus, because of the thinning of the main cyst wall, is recognized well.
All specimens studied in SEM show a plate overlap at the plate boundaries, conform the platye overlap system described by Gocht (1979, p.344-365). The reflection of this overlap results from the overlap of the periphragm on the neighbouring paraplate (Gocht 1987, fig.12; Brenner 1988, pl.18:3b, 5). The main cyst wall shows no structural changes near the parasutures. In one specimen margines and paraporoids are present (Gocht 1987, Brenner 1988, PL.18:5). The paraporoids form crater-shaped depressions in the middle of which there is a small wart-shaped elevation. In this species, no paraporoids could be determined within the "accession zone". This is conform presence of trichocysts on the thecae of recent dinoflagellates (Evitt 1985:13 e.a.).
In single specimens, a shift in the configuration of the sulcal plates could be determined. Standard for Lithodinia arcanitabulata is a triple point of paraplates 1c, 1""" and 2""". In single cases a quadruple point of paraplates 1c, sa, 1""" and 2""" can be present.
Despite the non-visibility of paratabulation in transmitted light, this species was assigned to Lithodinia, because it concurs with this genus in appearance and wall construction. As in Lithodinia jurassica, the archaeopyle is formed by the removel of the 4 separate apical plates (cf. Gocht 1975: 353).
In appearance and wall structure, Lithodinia arcanitabulata n. sp. is similar to Fibradinium variculum Stover and Helby 1987 from the Australian Lower Cretaceous, but differs from it in archaeopyle form and number of apical plates.
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Poulsen 1996, p. 67, Pl. 24, Fig. 1
Lithodinia arcanitabulata Brenner 1988
Remarks. Chlamydophorella ectotabulata Smelror 1989 may be a taxonomic junior synonym of this species; however, the paracingulum of L. arcanitabulata is expressed as a more pronounced depression than in C. ectotabulata. The paracingulum of C. ectotabulata is more similar to that of Lanterna species. Both species have a perforate ectophragm.
Recorded occurrence. Poland: Autissiodorensis Zone.
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Remarks: Iosifova 1996, p. 221, 223
When Brenner established this species he did not find any specimens with attached opercula in his material. Only one specimen with attached operculum has been found in the present study. The archeopyle of this species is apical, Type [tA], with the apical plates being detached as a single unit. The clearness of the paratabulation of this species varies greatly. Frequently there are no traces of paratabulation, including paracingulum and parasulcus, visible using the light microscope. Rarely only the paracingulum indentations
and parasulcus are present as described by Brenner. A few specimens present in this material possessed a low septa between the paraplates.
Occurrence: Tchernaya Retchka outcrop, the Ryazanian and probable Hauterivian sediments.
Dimensions: Length (without operculum): 32-36µm; width: 36-48µm.
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Holotype: Brenner, 1988, pl.18, fig.4
Age: Oxfordian-Early Kimmeridgian
Stratum typicum: Upper Jurassic, lower Malm gamma, platynota Zone (lower Kimmeridgian)
Locus typicus: Hörnlebruch near Neuffen, Germany
Translation Brenner 1988: LPP
--------------------------------------------------------------------------------------------------------------------------------------------------
Brenner 1988, p. 61-63, pl.18, fig.3-5
Diagnosis: Oval to polygonal dinoflagellate cyst with apical archaeopyle and a triple-layered main cyst wall, which consist of a thin "inner membrane", a coarsely porate to cavernous "main cyst wall" and a thin "outer membrane". In transmitted light the parasulcus is recognizeable as a by the clear reduction of thickness of the main cyst wall. The paracingulum is indicated, the paratabulation cannot be recognized. In SEM, the paraplate margins are clearly indicated.
Dimensions of holotype: length 54 µm, width 68 µm, cyst wall 3-6 µm.
Description:
Dinoflagellate cyst with ovoidal to polygonal appearance and gonyaulacoidal paratabulation. The archaeopyle is apical type 4A, the operculum tetra-otho (sensu Wille, 1985). In the total material studied, no single operculum of the decribed species was encountered, which points to a separation of the apical plates. The cyst diameter cyst is 55-70 µm. The wall thickness wall is 3-6 µm; it consists of a smooth, 0.1 µm thick "inner membrane", a foamy to cavernous "main cyst wall", as it is similarly present in Aldorfia aldorfensis and Eodinia pachytheca (cf. Gocht 1975a and 1975b), and a porous "outer membrane" which is also 0.1 µm thick.
In transmitted light, the paracingulum is hard to recognize, the parasulcus, because of the thinning of the main cyst wall, is recognized well.
All specimens studied in SEM show a plate overlap at the plate boundaries, conform the platye overlap system described by Gocht (1979, p.344-365). The reflection of this overlap results from the overlap of the periphragm on the neighbouring paraplate (Gocht 1987, fig.12; Brenner 1988, pl.18:3b, 5). The main cyst wall shows no structural changes near the parasutures. In one specimen margines and paraporoids are present (Gocht 1987, Brenner 1988, PL.18:5). The paraporoids form crater-shaped depressions in the middle of which there is a small wart-shaped elevation. In this species, no paraporoids could be determined within the "accession zone". This is conform presence of trichocysts on the thecae of recent dinoflagellates (Evitt 1985:13 e.a.).
In single specimens, a shift in the configuration of the sulcal plates could be determined. Standard for Lithodinia arcanitabulata is a triple point of paraplates 1c, 1""" and 2""". In single cases a quadruple point of paraplates 1c, sa, 1""" and 2""" can be present.
Despite the non-visibility of paratabulation in transmitted light, this species was assigned to Lithodinia, because it concurs with this genus in appearance and wall construction. As in Lithodinia jurassica, the archaeopyle is formed by the removel of the 4 separate apical plates (cf. Gocht 1975: 353).
In appearance and wall structure, Lithodinia arcanitabulata n. sp. is similar to Fibradinium variculum Stover and Helby 1987 from the Australian Lower Cretaceous, but differs from it in archaeopyle form and number of apical plates.
--------------------------------------------------------------------------------------------------------------------------------------------------
Poulsen 1996, p. 67, Pl. 24, Fig. 1
Lithodinia arcanitabulata Brenner 1988
Remarks. Chlamydophorella ectotabulata Smelror 1989 may be a taxonomic junior synonym of this species; however, the paracingulum of L. arcanitabulata is expressed as a more pronounced depression than in C. ectotabulata. The paracingulum of C. ectotabulata is more similar to that of Lanterna species. Both species have a perforate ectophragm.
Recorded occurrence. Poland: Autissiodorensis Zone.
--------------------------------------------------------------------------------------------------------------------------------------------------
Remarks: Iosifova 1996, p. 221, 223
When Brenner established this species he did not find any specimens with attached opercula in his material. Only one specimen with attached operculum has been found in the present study. The archeopyle of this species is apical, Type [tA], with the apical plates being detached as a single unit. The clearness of the paratabulation of this species varies greatly. Frequently there are no traces of paratabulation, including paracingulum and parasulcus, visible using the light microscope. Rarely only the paracingulum indentations
and parasulcus are present as described by Brenner. A few specimens present in this material possessed a low septa between the paraplates.
Occurrence: Tchernaya Retchka outcrop, the Ryazanian and probable Hauterivian sediments.
Dimensions: Length (without operculum): 32-36µm; width: 36-48µm.
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