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Tabulodinium senarium
Tabulodinium senarium Dodekova, 1990; Emendation: Riding and Helby, 2001d, p.89.
Taxonomic junior synonym: Pareodinia tamarensis (name not validly published), according to Riding and Helby (2001d, p.89).
Holotype: Dodecova, 1990, pl.4, figs.4-5
Locus typicus: borehole S-12 Gornjak, Dobric Formation, NE Bulgaria
Stratum typicum: Late Bathonian-?early Callovian
Original diagnosis: Dodekova, 1990, p.23-24 Same as the generic diagnosis.
At the present stage of knowledge the generic diagnosis coincides with that of the type species. It can be elaborated and made more precise after new data or new species having similar morphology are found. The cyst is proximate, pareodinioid, ovoidal with intermediately long apical horn, with or without embrio of antapical projection. The tabulation is indicated by pandasutural bands and the plates are occupied by sculptural elements of low relief. Tabulation formula: ?pr, ?4", 3-?a, 6", 6c, 6""", 1p, 1"""", 0-6s. Archeopyle-intercalary, type I or 3I. Cyst"s size-intermediate. "Kalyptra" is commonly present, but may be lacking some times. It is put in quotes here for it resembles ectophragm. Apicular structure on the apical horn i s rarely observed, usually lacking.
Dimensions (in µm). Holotype: length: 68, breadth: 38, length of apical horn: 13, breadth of cingulum: 5, thickness of the wall: 1.5. Range: length: 56-68, breadth: 33-41, length of apical horn: 11-13, width of cingulum: 4-5, thickness of the wall: 1.5 (measured 17 specimens).
Description: Dodekova, 1990, p.24-25
Cyst ovoidal to drop-like with strong and blunt moderate in length apical horn. The cyst is divided in two, nearly equal halves by broad helicoidal cingulum. The epicyst may be slightly longer than the hypocyst. The cingulum is marked on the lateral outline by a subconcavity. It is the broadest part of the cyst there. The epicyst is roundly conical, and the hypocyst--widely rounded, hemispheric. Tabulation indicated by pandasutural bands, which are clearly or poorly pronounced. The plates are occupied by thick, porous, spongy matter with perforations and areolae on their surface. Around the apex and apical horn this ornamentation is thinner and more poorly marked. Relatively thickest is the ornamentation on the hypocyst and the antapical plate, where in some specimens a protrusion resembling embrio of antapical horn is formed. The pandasutural bands are lacking spongy matter, but have fine sculpture of a type, which is hard to be determined - scabrate or punctate. The pandasutural bands around the apex are indistinct, whereupon the tabulation scheme in that part of thecystremains unclear. The tabulation formula of the species with some uncertainty for the apex is the following: "?pr, ?4", 3-?a, 6", 6c, 6""", 1p, 1"""", ?5-6s. A good deal of tabulation schemes for different specimens have been made in order a generalised tabulation scheme to be proposed (fig. 3). The holotype proved to be of almost importance for the development of such scheme. In the holotype and some other specimens, two pinches in the upper part of the apical horn suggesting the presence of preapical plates are available. The presence of 4 apical plates is admitted. The number, size, shape and position of the plates of the precingular, cingular and postcingular series are shown on fig. 3. The first postcingular plate is very small, being considered by some authors to be a sulcal plate, reducing that way the number of postcingular plates to 5. Three intercalary plates, a big one-central 2a and on both sides of it two symmetrical small ones 1a and 3a, are identified. The vague ornamentation in the upper part of the epicyst makes the determination of the exact number of anterior intercalary plates difficult.
The posterior intercalary plate 1p is large, Iying under plate 2""" and partly under plate 3""", and sometimes may be fallaciously considered to be second antapical plate.
Archeopyle: intercalary, type I(2a) or 3I. In a greater number of specimens the archeopyle is type I with operculum free--plate 2a. In other specimens, having their archeopyle formed by plate 2a, the intercalary plates 1a and 3a are slightly opened, remaining attached to the cyst (pl. IV, figs 8-10). In some specimens, though very rarely, all the three dorsal intercalary plates are lacking archeopyle type 3I. So far, it remains unclear whether there is any gradation and gradualness in the development of the archeopyle from I to 3I, or the lateral plates (1a and 3a) are labile zones falling away under mechanical influence.
The sulcal plates, when well-marked, are ?5-6s. Commonly they are hardly identifiable. The specification of the tabulation is made difficult because of the presence of "kalyptra". The majority of specimens studied have "kalyptra" (all microphotographs illustrated except the holotype). By analogy with the kalyptra in the genus Pareodinia (sensu Gocht, 1970, pp. 154, 155 and Wiggins, 1975, pp. 98, 99). I do consider its presence to be a primary one, and its absence in some specimens, including the holotype, as due to mechanical dismemberment. The "kalyptra" of the new taxon looks much more like a thin ectophragm than a concentration of organic matter. It is variously shaped due to the different state of preservation. It has coarse superficial reticulation and, in some specimens? Iikeness of sutural ribs. In some parts of the cyst this "outer layer" looks intimately connected with the ornamentation of the autophragm. The specimen shown on pl. IV, figs. 8-10 is having its archeopyle with completely preserved "kalyptra". The availability of specimens lacking "kalyptra" is hitherto preventing the new taxon to be considered as a cavate cyst.
Taxonomic junior synonym: Pareodinia tamarensis (name not validly published), according to Riding and Helby (2001d, p.89).
Holotype: Dodecova, 1990, pl.4, figs.4-5
Locus typicus: borehole S-12 Gornjak, Dobric Formation, NE Bulgaria
Stratum typicum: Late Bathonian-?early Callovian
Original diagnosis: Dodekova, 1990, p.23-24 Same as the generic diagnosis.
At the present stage of knowledge the generic diagnosis coincides with that of the type species. It can be elaborated and made more precise after new data or new species having similar morphology are found. The cyst is proximate, pareodinioid, ovoidal with intermediately long apical horn, with or without embrio of antapical projection. The tabulation is indicated by pandasutural bands and the plates are occupied by sculptural elements of low relief. Tabulation formula: ?pr, ?4", 3-?a, 6", 6c, 6""", 1p, 1"""", 0-6s. Archeopyle-intercalary, type I or 3I. Cyst"s size-intermediate. "Kalyptra" is commonly present, but may be lacking some times. It is put in quotes here for it resembles ectophragm. Apicular structure on the apical horn i s rarely observed, usually lacking.
Dimensions (in µm). Holotype: length: 68, breadth: 38, length of apical horn: 13, breadth of cingulum: 5, thickness of the wall: 1.5. Range: length: 56-68, breadth: 33-41, length of apical horn: 11-13, width of cingulum: 4-5, thickness of the wall: 1.5 (measured 17 specimens).
Description: Dodekova, 1990, p.24-25
Cyst ovoidal to drop-like with strong and blunt moderate in length apical horn. The cyst is divided in two, nearly equal halves by broad helicoidal cingulum. The epicyst may be slightly longer than the hypocyst. The cingulum is marked on the lateral outline by a subconcavity. It is the broadest part of the cyst there. The epicyst is roundly conical, and the hypocyst--widely rounded, hemispheric. Tabulation indicated by pandasutural bands, which are clearly or poorly pronounced. The plates are occupied by thick, porous, spongy matter with perforations and areolae on their surface. Around the apex and apical horn this ornamentation is thinner and more poorly marked. Relatively thickest is the ornamentation on the hypocyst and the antapical plate, where in some specimens a protrusion resembling embrio of antapical horn is formed. The pandasutural bands are lacking spongy matter, but have fine sculpture of a type, which is hard to be determined - scabrate or punctate. The pandasutural bands around the apex are indistinct, whereupon the tabulation scheme in that part of thecystremains unclear. The tabulation formula of the species with some uncertainty for the apex is the following: "?pr, ?4", 3-?a, 6", 6c, 6""", 1p, 1"""", ?5-6s. A good deal of tabulation schemes for different specimens have been made in order a generalised tabulation scheme to be proposed (fig. 3). The holotype proved to be of almost importance for the development of such scheme. In the holotype and some other specimens, two pinches in the upper part of the apical horn suggesting the presence of preapical plates are available. The presence of 4 apical plates is admitted. The number, size, shape and position of the plates of the precingular, cingular and postcingular series are shown on fig. 3. The first postcingular plate is very small, being considered by some authors to be a sulcal plate, reducing that way the number of postcingular plates to 5. Three intercalary plates, a big one-central 2a and on both sides of it two symmetrical small ones 1a and 3a, are identified. The vague ornamentation in the upper part of the epicyst makes the determination of the exact number of anterior intercalary plates difficult.
The posterior intercalary plate 1p is large, Iying under plate 2""" and partly under plate 3""", and sometimes may be fallaciously considered to be second antapical plate.
Archeopyle: intercalary, type I(2a) or 3I. In a greater number of specimens the archeopyle is type I with operculum free--plate 2a. In other specimens, having their archeopyle formed by plate 2a, the intercalary plates 1a and 3a are slightly opened, remaining attached to the cyst (pl. IV, figs 8-10). In some specimens, though very rarely, all the three dorsal intercalary plates are lacking archeopyle type 3I. So far, it remains unclear whether there is any gradation and gradualness in the development of the archeopyle from I to 3I, or the lateral plates (1a and 3a) are labile zones falling away under mechanical influence.
The sulcal plates, when well-marked, are ?5-6s. Commonly they are hardly identifiable. The specification of the tabulation is made difficult because of the presence of "kalyptra". The majority of specimens studied have "kalyptra" (all microphotographs illustrated except the holotype). By analogy with the kalyptra in the genus Pareodinia (sensu Gocht, 1970, pp. 154, 155 and Wiggins, 1975, pp. 98, 99). I do consider its presence to be a primary one, and its absence in some specimens, including the holotype, as due to mechanical dismemberment. The "kalyptra" of the new taxon looks much more like a thin ectophragm than a concentration of organic matter. It is variously shaped due to the different state of preservation. It has coarse superficial reticulation and, in some specimens? Iikeness of sutural ribs. In some parts of the cyst this "outer layer" looks intimately connected with the ornamentation of the autophragm. The specimen shown on pl. IV, figs. 8-10 is having its archeopyle with completely preserved "kalyptra". The availability of specimens lacking "kalyptra" is hitherto preventing the new taxon to be considered as a cavate cyst.