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Tectatodinium
From Williams et al., 2017:
[Tectatodinium, Wall, 1967, p. 112–113; Emendation: Head, 1994a, p. 306
Type species: Tectatodinium pellitum, Wall, 1967 (pl.16, fig.12)]
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Original description: [Wall, 1967]:
Description:
Spherical to ovoid dinoflagellate cysts without apical, antapical, or any other form of projections. Test wall double (resembling tectate pollen), the outer layer being thicker and less compact or homogenous than the inner. Test penetrated by a large dorsal precingular archeopyle representing the loss of one plate. A girdle or ventral sulcus rarely present.
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Modified description:
Stover and Evitt, 1978, p. 193-194:
Synopsis:
Cysts proximate, subspherical to ellipsoidal; body composed of appressed endophragm and periphragm; surface smooth or faintly ornamented; paratabulation indicated by precingular, Type P, archeopyle.
Description:
Shape: Subspherical to ellipsoidal.
Wall relationships: Endophragm and periphragm appressed; periphragm usually thicker than endophragm.
Wall features: No parasutural features. Surface smooth to faintly ornamented, and periphragm generally shows some kind of internal texture.
Paratabulation: Normally expressed by archeopyle only; other indications vague or inconsistent.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Tectatodinium differs from Pyxidinopsis in that it is smooth or faintly ornamented rather than reticulate. It differs from Operculodinium in lacking nontabular cones, spines, or processes; and from Tapeinosphaeridium in having a thick two-layered wall instead of a thin, commonly folded autophragm.
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Emended description:
Head, 1994a:
Diagnosis:
Cysts proximate and spherical to slightly ovoid and may possess a slight apical protuberance. Wall comprises a thin pedium and a lanate to spongy, distally open luxuria. Wall is weakly pigmented or non-pigmented. Archeopyle is precingular and formed by loss of the third precingular paraplate. Adcingular archeopyle angles are well defined. Operculum monoplacoid and free. Other indications of paratabulation are weakly or not expressed.
Discussion:
Contrary to the original diagnosis of Tectatodinium, the wall of the nomenclatural type, T. pellitum, does not resemble a tectate pollen. Instead, the spongy nature of the luxuria is a diagnostic feature of this genus. However, it is predicted from the theoretical progression of wall development in Below (1987, fig. 34.2-34.3) that the genus Tectatodinium might include specimens whose luxuria is lanate (felt-like) or, in the case of thicker-walled forms, possessing some rudimentary level of differentiation. Tectatodinium is essentially proximate but short, sparsely scattered, nontabular fibrils might occur on the surface of the luxuria. Tectatodinium is not intended to include species consistently showing two or more precingular paraplates involved in archeopyle formation; however species with some variability in the number of plates involved (ranging from one to two or more paraplates) might be included in Tectatodinium.
Affinities/Comparison: (p. 308)
Filisphaera Bujak 1984 emend. Head 1994 has a microreticulate luxuria formed of high septa (text-figure 3). Habibacysta has a columellae and a tegillate wall. Bitectatodinium Wilson 1973 has a 2P archeopyle and the wall, judging from the nomenclatural type B. tepikiense, is characterized by a luxuria comprising lamellae that arise from thickened bases which may appear as granules or rods under LM (e.g., Wilson 1973; Reid 1974, pl. 1, figs. 3-5; see text-figure 3) although usually only lamellar elements are seen under SEM (e.g., Jux 1976; Turon 1984, pl. 5, figs. 2, 3; Head and Wrenn 1992, pl. 7, figs. 5-10).
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Tectatodinium Wall, 1967, emend. Head, 1994a. Emendation from Head (1994a, p.306), Cysts proximate and spherical to slightly ovoid and may possess a slight apical protuberance. Wall comprises a thin pedium and a lanate to spongy, distally open luxuria. Wall is weakly pigmented or non-pigmented. Archeopyle is precingular and formed by loss of the 3". Adcingular archeopyle angles are well defined. Operculum monoplacoid and free. Other indications or paratabulation are weakly or not expressed. Filisphaera has a microreticulate luxuria formed of high septa. Habibacysta has columellae and a tegillate wall. Bitectatodinium has a 2P archeopyle and the wall is composed of luxuria comprising lamellae that arise from thickened bases which may appear as granules or rods under LM although only lamellar elements are seen under SEM.
[Tectatodinium, Wall, 1967, p. 112–113; Emendation: Head, 1994a, p. 306
Type species: Tectatodinium pellitum, Wall, 1967 (pl.16, fig.12)]
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Original description: [Wall, 1967]:
Description:
Spherical to ovoid dinoflagellate cysts without apical, antapical, or any other form of projections. Test wall double (resembling tectate pollen), the outer layer being thicker and less compact or homogenous than the inner. Test penetrated by a large dorsal precingular archeopyle representing the loss of one plate. A girdle or ventral sulcus rarely present.
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Modified description:
Stover and Evitt, 1978, p. 193-194:
Synopsis:
Cysts proximate, subspherical to ellipsoidal; body composed of appressed endophragm and periphragm; surface smooth or faintly ornamented; paratabulation indicated by precingular, Type P, archeopyle.
Description:
Shape: Subspherical to ellipsoidal.
Wall relationships: Endophragm and periphragm appressed; periphragm usually thicker than endophragm.
Wall features: No parasutural features. Surface smooth to faintly ornamented, and periphragm generally shows some kind of internal texture.
Paratabulation: Normally expressed by archeopyle only; other indications vague or inconsistent.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Tectatodinium differs from Pyxidinopsis in that it is smooth or faintly ornamented rather than reticulate. It differs from Operculodinium in lacking nontabular cones, spines, or processes; and from Tapeinosphaeridium in having a thick two-layered wall instead of a thin, commonly folded autophragm.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Head, 1994a:
Diagnosis:
Cysts proximate and spherical to slightly ovoid and may possess a slight apical protuberance. Wall comprises a thin pedium and a lanate to spongy, distally open luxuria. Wall is weakly pigmented or non-pigmented. Archeopyle is precingular and formed by loss of the third precingular paraplate. Adcingular archeopyle angles are well defined. Operculum monoplacoid and free. Other indications of paratabulation are weakly or not expressed.
Discussion:
Contrary to the original diagnosis of Tectatodinium, the wall of the nomenclatural type, T. pellitum, does not resemble a tectate pollen. Instead, the spongy nature of the luxuria is a diagnostic feature of this genus. However, it is predicted from the theoretical progression of wall development in Below (1987, fig. 34.2-34.3) that the genus Tectatodinium might include specimens whose luxuria is lanate (felt-like) or, in the case of thicker-walled forms, possessing some rudimentary level of differentiation. Tectatodinium is essentially proximate but short, sparsely scattered, nontabular fibrils might occur on the surface of the luxuria. Tectatodinium is not intended to include species consistently showing two or more precingular paraplates involved in archeopyle formation; however species with some variability in the number of plates involved (ranging from one to two or more paraplates) might be included in Tectatodinium.
Affinities/Comparison: (p. 308)
Filisphaera Bujak 1984 emend. Head 1994 has a microreticulate luxuria formed of high septa (text-figure 3). Habibacysta has a columellae and a tegillate wall. Bitectatodinium Wilson 1973 has a 2P archeopyle and the wall, judging from the nomenclatural type B. tepikiense, is characterized by a luxuria comprising lamellae that arise from thickened bases which may appear as granules or rods under LM (e.g., Wilson 1973; Reid 1974, pl. 1, figs. 3-5; see text-figure 3) although usually only lamellar elements are seen under SEM (e.g., Jux 1976; Turon 1984, pl. 5, figs. 2, 3; Head and Wrenn 1992, pl. 7, figs. 5-10).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Tectatodinium Wall, 1967, emend. Head, 1994a. Emendation from Head (1994a, p.306), Cysts proximate and spherical to slightly ovoid and may possess a slight apical protuberance. Wall comprises a thin pedium and a lanate to spongy, distally open luxuria. Wall is weakly pigmented or non-pigmented. Archeopyle is precingular and formed by loss of the 3". Adcingular archeopyle angles are well defined. Operculum monoplacoid and free. Other indications or paratabulation are weakly or not expressed. Filisphaera has a microreticulate luxuria formed of high septa. Habibacysta has columellae and a tegillate wall. Bitectatodinium has a 2P archeopyle and the wall is composed of luxuria comprising lamellae that arise from thickened bases which may appear as granules or rods under LM although only lamellar elements are seen under SEM.