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Endoscrinium bessebae
Endoscrinium bessebae Below, 1981
Originally (and now) Endoscrinium, subsequently Scriniodinium.
Jan du Chêne et al., 1986, transferred this species to Scriniodinium Klement, 1957. Lentin and Williams, 1993, retained it in Endoscrinium.
Holotype: Below, 1981, pl.7, figs.7a-b; Jan du Chêne et al., 1986a, pl.104, figs.12-13; Fensome et al., 1991, figs.4-7-p.589
Paratype: Below, 1981, pl.7, fig.8
Locus typicus: Chichaoua I borehole, SW Morocco
Stratum typicum: Barremian
Translation Below, 1981: Fensome et al., 1991, p. 590-592
Original diagnosis: Below, 1981, p. 48
Circumcavate to weakly camocavate cyst. Endocyst spheroidal to subpentagonal, without an apical horn. Endophragm smooth, without ornamentation or parasutures. Endoarcheopyle middorsal, precingular. Endo-operculum with intratabular, horseshoe-shaped sash. Subspheroidal pericyst composed of smooth periphragm and with a short apical horn. Paratabulation gonyaulacoid ?4", 6", Xc, 6""", pc, 1"""". Parasutures marked by low ridges with a few sutural spinules and gonal tufts of two or three spines with simple or branched ends. Paracingulum equatorial, spiral.
Parasulcus slightly sigmoidal. Periarcheopyle large, corresponding to paraplate 3". Consequently, the archeopyle formula is P(3"")/(P3""). Endo- and periphragm are usually separated by a pericoel. The two membranes are closest, and in exceptional cases in contact, ventrally.
Original description: Below, 1981, p. 48-49
In contrast to the transparent periphragm, in transmitted light the endophragm appears to be milky, probably because of a different ultrastructure. It forms the subspheroidal to strongly rounded pentagonal inner body, which is surmounted apically only rarely by a low bulge. With one exception there are no indications of paratabulation or ornamentation. The middorsal, horseshoe-shaped opercular plate of the endoarcheopyle bears an intratabular denticulate sash which parallels the
opercular margin. [This sash] is highest anteriorly and becomes gradually lower towards both of its posterior ends. It is not vertical to the surface of the endocyst but is slanted towards the centre of the paraplate (see [Below, 1981a] text-fig.51).
The pericyst has a hollow tubular apical horn which is open only proximally, coronet-shaped, denticulate and expanded distally or tapers to a bifid or polyfurcate tip. Delicate ridges, commonly becoming reduced to almost invisible lines, divide the pericyst completely into paraplates. It was not possible to completely reconstruct the paratabulation. The exact division of the apical region and the exact number of the paraplates of the paracingulum remain unknown. It may be assumed that either five or six paraplates occur here [in the paracingulum]. Six precingular paraplates, incuding a reduced 6", six postcingulars, one rhomboidal pc and 1"""" were recognized and their relationship is shown in [Below, 1981a] text-fig.49. The parasutural ridges bear short, unbranched, curved spinules or solid appendages with acuminate or thickened oblate tips. As a rule, solid gonal appendages of the first order are branched bifurcately or trifurcately, those of the second order are usually bifidly branched. In this manner, tufts of appendages mark the contact of several paraplates even when their position cannot be determined due to complete reduction of the parasutural ridges. Often, parasutures are emphasized by more or less substantial folding of the periphragm. In numerous specimens this results in an angular, polygonal outline ([Below, 1981a] pl.7, fig.6).
The periarcheopyle is horseshoe-shaped in outline. It is larger than the endoarcheopyle.
Originally (and now) Endoscrinium, subsequently Scriniodinium.
Jan du Chêne et al., 1986, transferred this species to Scriniodinium Klement, 1957. Lentin and Williams, 1993, retained it in Endoscrinium.
Holotype: Below, 1981, pl.7, figs.7a-b; Jan du Chêne et al., 1986a, pl.104, figs.12-13; Fensome et al., 1991, figs.4-7-p.589
Paratype: Below, 1981, pl.7, fig.8
Locus typicus: Chichaoua I borehole, SW Morocco
Stratum typicum: Barremian
Translation Below, 1981: Fensome et al., 1991, p. 590-592
Original diagnosis: Below, 1981, p. 48
Circumcavate to weakly camocavate cyst. Endocyst spheroidal to subpentagonal, without an apical horn. Endophragm smooth, without ornamentation or parasutures. Endoarcheopyle middorsal, precingular. Endo-operculum with intratabular, horseshoe-shaped sash. Subspheroidal pericyst composed of smooth periphragm and with a short apical horn. Paratabulation gonyaulacoid ?4", 6", Xc, 6""", pc, 1"""". Parasutures marked by low ridges with a few sutural spinules and gonal tufts of two or three spines with simple or branched ends. Paracingulum equatorial, spiral.
Parasulcus slightly sigmoidal. Periarcheopyle large, corresponding to paraplate 3". Consequently, the archeopyle formula is P(3"")/(P3""). Endo- and periphragm are usually separated by a pericoel. The two membranes are closest, and in exceptional cases in contact, ventrally.
Original description: Below, 1981, p. 48-49
In contrast to the transparent periphragm, in transmitted light the endophragm appears to be milky, probably because of a different ultrastructure. It forms the subspheroidal to strongly rounded pentagonal inner body, which is surmounted apically only rarely by a low bulge. With one exception there are no indications of paratabulation or ornamentation. The middorsal, horseshoe-shaped opercular plate of the endoarcheopyle bears an intratabular denticulate sash which parallels the
opercular margin. [This sash] is highest anteriorly and becomes gradually lower towards both of its posterior ends. It is not vertical to the surface of the endocyst but is slanted towards the centre of the paraplate (see [Below, 1981a] text-fig.51).
The pericyst has a hollow tubular apical horn which is open only proximally, coronet-shaped, denticulate and expanded distally or tapers to a bifid or polyfurcate tip. Delicate ridges, commonly becoming reduced to almost invisible lines, divide the pericyst completely into paraplates. It was not possible to completely reconstruct the paratabulation. The exact division of the apical region and the exact number of the paraplates of the paracingulum remain unknown. It may be assumed that either five or six paraplates occur here [in the paracingulum]. Six precingular paraplates, incuding a reduced 6", six postcingulars, one rhomboidal pc and 1"""" were recognized and their relationship is shown in [Below, 1981a] text-fig.49. The parasutural ridges bear short, unbranched, curved spinules or solid appendages with acuminate or thickened oblate tips. As a rule, solid gonal appendages of the first order are branched bifurcately or trifurcately, those of the second order are usually bifidly branched. In this manner, tufts of appendages mark the contact of several paraplates even when their position cannot be determined due to complete reduction of the parasutural ridges. Often, parasutures are emphasized by more or less substantial folding of the periphragm. In numerous specimens this results in an angular, polygonal outline ([Below, 1981a] pl.7, fig.6).
The periarcheopyle is horseshoe-shaped in outline. It is larger than the endoarcheopyle.