Back
Chichaouadinium arabicum
Chichaouadinium arabicum, Below, 1981
Holotype: Below, 1981, pl.10, figs.13a-c, text-fig.81h (non 81e); Fensome et al., 1991, figs.1-3 - p.571
Locus typicus: Chichaoua I borehole, SW Morocco
Stratum typicum: Albian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Below, 1981, p. 123-124]:
Diagnosis:
Cornucavate cyst with a two-layered wall, peridinioid tabulation and a rhomboid, pentagonal to lacrymoid outline. The endocyst fills the pericyst completely except at the polar appendages. Pericyst with a short, conical, distally closed and flattened or indented apical horn which arises gradually from the pericyst. Only a minute, pointed, hollow, right antapical horn is developed. The pericyst is divided into two equal valves by the planar to very weakly spiral paracingulum, which is indented and broad. With the exception of the slightly ornamented paracingulum, the periphragm has a dense covering of evenly distributed, stout, short, hollow echinae, which are button-shaped distally. The form of the appendages does not vary, the number of appendages per cyst varies only within narrow limits. Dorsally, narrow pandasutural bands mark the limits of the paraplates, whereas ventrally the parasutures and the parasulcus are masked by echinae. The position of the parasulcus can be identified only on the basis of the interruption and slight offset of the transverse furrow.
The archeopyle type varies between Ia(2a) + 3Pa(3""-5"") or I(2a) + 3Pa(3""-5"").
Description:
Only a few supplemental remarks concerning the archeopyle will be added to the diagnosis. Endocyst and pericyst are in contact; only at the apex is there a small pericoel. Consequently, only a single operculum develops. During excystment, it breaks down into components. The precingular paraplates remain attached to the cyst along the anterior paracingular margin. Since it was observed only in deformed specimens, the removal of one or two precingulars is attributable to mechanical effects during fossilization or maceration. In contrast, the "standard hexa" paraplate 2a is missing in about half of the population and in the other half is still connected to parasuture Hl and, thus, to paraplate 3". Numerous specimens, including especially deformed individuals, were examined to determine whether paraplates la and 3a are involved in the development of the archeopyle as attached opercular pieces. Only the parasutures la/2" and 3a/6" split, but only rarely; however, parasutures la/2"-3" or 3a/4"-3" never split.
Holotype: Below, 1981, pl.10, figs.13a-c, text-fig.81h (non 81e); Fensome et al., 1991, figs.1-3 - p.571
Locus typicus: Chichaoua I borehole, SW Morocco
Stratum typicum: Albian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Below, 1981, p. 123-124]:
Diagnosis:
Cornucavate cyst with a two-layered wall, peridinioid tabulation and a rhomboid, pentagonal to lacrymoid outline. The endocyst fills the pericyst completely except at the polar appendages. Pericyst with a short, conical, distally closed and flattened or indented apical horn which arises gradually from the pericyst. Only a minute, pointed, hollow, right antapical horn is developed. The pericyst is divided into two equal valves by the planar to very weakly spiral paracingulum, which is indented and broad. With the exception of the slightly ornamented paracingulum, the periphragm has a dense covering of evenly distributed, stout, short, hollow echinae, which are button-shaped distally. The form of the appendages does not vary, the number of appendages per cyst varies only within narrow limits. Dorsally, narrow pandasutural bands mark the limits of the paraplates, whereas ventrally the parasutures and the parasulcus are masked by echinae. The position of the parasulcus can be identified only on the basis of the interruption and slight offset of the transverse furrow.
The archeopyle type varies between Ia(2a) + 3Pa(3""-5"") or I(2a) + 3Pa(3""-5"").
Description:
Only a few supplemental remarks concerning the archeopyle will be added to the diagnosis. Endocyst and pericyst are in contact; only at the apex is there a small pericoel. Consequently, only a single operculum develops. During excystment, it breaks down into components. The precingular paraplates remain attached to the cyst along the anterior paracingular margin. Since it was observed only in deformed specimens, the removal of one or two precingulars is attributable to mechanical effects during fossilization or maceration. In contrast, the "standard hexa" paraplate 2a is missing in about half of the population and in the other half is still connected to parasuture Hl and, thus, to paraplate 3". Numerous specimens, including especially deformed individuals, were examined to determine whether paraplates la and 3a are involved in the development of the archeopyle as attached opercular pieces. Only the parasutures la/2" and 3a/6" split, but only rarely; however, parasutures la/2"-3" or 3a/4"-3" never split.