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Occisucysta coummia
Occisucysta coummia Below, 1981
Now Tehamadinium. Originally Occisucysta, subsequently (and now) Tehamadinium.
Holotype: Below, 1981, pl.8, fig.6; Jan du Chêne et al., 1986(a), pl.118, figs.7-9; Jan du Chêne et al., 1986(b), pl.14, figs.1-4; Fensome et al., 1991, figs.1-2 - p.631
Age: Albian
Original diagnosis: Below, 1981, p. 61: Occisucysta coummia
Spherical, proximate cyst with a gonyaulacoid tabulation. Hypocyst and epicyst of equal size, the latter with an apical hom. Paracingulum equatorial, weakly spiral, subdivided. Division of parasulcus rarely indicated. Paratabulation 4', 6", Xc, 6''', lpc, 1'''', Xs. The spongy periphragm bears intratabular spines and the rows following the parasutures develop spines that are basally fused. The endophragm is unstructured and smooth. Archeopyle of type 2P(2''-3'').
Original description: Below, 1981, p. 61
Occisucysta coummia n.sp. is spheroidal. Two membranes consitute the body. In contrast to the often thick, unstructured endophragm, the outer layer is spongy ([Below, 1981a] pl.13, fig.10). Intratabular and parasutural appendages arise from this substrate ([Below, 1981a] pl.13, fig.10). They are short, basally expanded, distally usually pointed spines, but are occasionally also thin, long spines continuously tapering distally and occasionally bifurcate at their tips. Commonly, adjacent spines are joined proximally and occasionally also medially, forming more or less large groups and rows. In extreme instances, intratabular pseudosutures develop congruent to the parasutures. The distribution density of the appendages varies considerably ([Below, 1981a] pl.13, fig.11). The parasutures are marked by contiguous spines that are usually united basally. However, on most specimens there are a few appendages connected distally. On the other hand, there are also specimens with isolated parasutural spines arranged in rows. Consequently, where additional, strongly developed, intratabular spines occur, it becomes impossible to determine the paratabulation. The paratabulation is the same as that of Occisucysta tenuiceras (Eisenack 1958) comb. nov. consequently, reference to the description for that species will suffice and only a few supplementary statements are made here. The exact number of paracingular paraplates is unknown. The parasulcus is usually only recongnizable as a broad zone extending somewhat onto the epicyst and extending on the hypocyst to the antapical 1''''. However, this region is divided into one curved lps, a rhombic lpc, a rectangular, small ra, an elongate rs and a small 1'''.
Parasutural rows of spines meeting apically constitute the scaffold of the cylindrical or broadly based, low, pyramidal apical horn, which distinctly surmounts the central body. The endophragm usually extends only as a low bulge into the cavity of the horn.
Emended diagnosis: Jan du Chêne et al., 1986, p. 23 for Tehamadinium coummia
Cyst proximate, subspheroidal to ovoidal in shape, with a paratabulation of gonyaulacoid type lpr, 4', 6", 6c, 5s, 6''', lp, 1''''. The cyst is prolonged by a short apical protuberance. The parasutural septa are low and surmounted by an alignment of spines linked by their bases. The autophragm is spongy and adomed with regularly disposed spines on the intratabular areas. Archeopyle precingular 2P (2 + 3 ). Operculum free compound.
Emended description: Jan du Chêne et al., 1986, p. 23 for Tehamadinium coummia
Proximate dinoflagellate cyst of subspherical to ovoidal shape having a paratabulation of gonyaulacoid type lpr 4 6 6c 5s 6 lp 1 . The cyst has a slight apical protuberance formed by the junction of the sutural septa delimiting the apical paraplates. The autophragm is spongy adorned with fine pointed spines regularly dispersed in an intratabular position. Spines also adorn the crests of the low sutural septa which define the paratabulation. The archeopyle is precingular 2P (2 + 3 ) with a compound free operculum. The paracingulum delimited by sutural septa comprises 6 cingular paraplates. It is weakly sinistral and is interrupted at the parasulcus. The outline of the parasulcus is always visible but the sulcal paraplates are discernible with difficulty the parasutural septa being only slightly elevated.
Now Tehamadinium. Originally Occisucysta, subsequently (and now) Tehamadinium.
Holotype: Below, 1981, pl.8, fig.6; Jan du Chêne et al., 1986(a), pl.118, figs.7-9; Jan du Chêne et al., 1986(b), pl.14, figs.1-4; Fensome et al., 1991, figs.1-2 - p.631
Age: Albian
Original diagnosis: Below, 1981, p. 61: Occisucysta coummia
Spherical, proximate cyst with a gonyaulacoid tabulation. Hypocyst and epicyst of equal size, the latter with an apical hom. Paracingulum equatorial, weakly spiral, subdivided. Division of parasulcus rarely indicated. Paratabulation 4', 6", Xc, 6''', lpc, 1'''', Xs. The spongy periphragm bears intratabular spines and the rows following the parasutures develop spines that are basally fused. The endophragm is unstructured and smooth. Archeopyle of type 2P(2''-3'').
Original description: Below, 1981, p. 61
Occisucysta coummia n.sp. is spheroidal. Two membranes consitute the body. In contrast to the often thick, unstructured endophragm, the outer layer is spongy ([Below, 1981a] pl.13, fig.10). Intratabular and parasutural appendages arise from this substrate ([Below, 1981a] pl.13, fig.10). They are short, basally expanded, distally usually pointed spines, but are occasionally also thin, long spines continuously tapering distally and occasionally bifurcate at their tips. Commonly, adjacent spines are joined proximally and occasionally also medially, forming more or less large groups and rows. In extreme instances, intratabular pseudosutures develop congruent to the parasutures. The distribution density of the appendages varies considerably ([Below, 1981a] pl.13, fig.11). The parasutures are marked by contiguous spines that are usually united basally. However, on most specimens there are a few appendages connected distally. On the other hand, there are also specimens with isolated parasutural spines arranged in rows. Consequently, where additional, strongly developed, intratabular spines occur, it becomes impossible to determine the paratabulation. The paratabulation is the same as that of Occisucysta tenuiceras (Eisenack 1958) comb. nov. consequently, reference to the description for that species will suffice and only a few supplementary statements are made here. The exact number of paracingular paraplates is unknown. The parasulcus is usually only recongnizable as a broad zone extending somewhat onto the epicyst and extending on the hypocyst to the antapical 1''''. However, this region is divided into one curved lps, a rhombic lpc, a rectangular, small ra, an elongate rs and a small 1'''.
Parasutural rows of spines meeting apically constitute the scaffold of the cylindrical or broadly based, low, pyramidal apical horn, which distinctly surmounts the central body. The endophragm usually extends only as a low bulge into the cavity of the horn.
Emended diagnosis: Jan du Chêne et al., 1986, p. 23 for Tehamadinium coummia
Cyst proximate, subspheroidal to ovoidal in shape, with a paratabulation of gonyaulacoid type lpr, 4', 6", 6c, 5s, 6''', lp, 1''''. The cyst is prolonged by a short apical protuberance. The parasutural septa are low and surmounted by an alignment of spines linked by their bases. The autophragm is spongy and adomed with regularly disposed spines on the intratabular areas. Archeopyle precingular 2P (2 + 3 ). Operculum free compound.
Emended description: Jan du Chêne et al., 1986, p. 23 for Tehamadinium coummia
Proximate dinoflagellate cyst of subspherical to ovoidal shape having a paratabulation of gonyaulacoid type lpr 4 6 6c 5s 6 lp 1 . The cyst has a slight apical protuberance formed by the junction of the sutural septa delimiting the apical paraplates. The autophragm is spongy adorned with fine pointed spines regularly dispersed in an intratabular position. Spines also adorn the crests of the low sutural septa which define the paratabulation. The archeopyle is precingular 2P (2 + 3 ) with a compound free operculum. The paracingulum delimited by sutural septa comprises 6 cingular paraplates. It is weakly sinistral and is interrupted at the parasulcus. The outline of the parasulcus is always visible but the sulcal paraplates are discernible with difficulty the parasutural septa being only slightly elevated.