Back
Deflandrea gallia
Deflandrea gallia Davey and Verdier, 1973
Now Isabelidinium. Originally Deflandrea, subsequently Spinidinium, thirdly (and now) Isabelidinium.
Holotype: Davey and Verdier, 1973, pl.3, figs.1,3
Locus typicus: Saint Florentin, Chemin du CimentiÞre, France
Stratum typicum: Late Albian
Original diagnosis: Davey and Verdier, 1973, p. 196-197
This species of Deflandrea has an elongate pentagonal outline, the epitract being
longer than the hypotract, with a subspherical to ovoidal inner body. The sides of the epitract are moderately convex and there is a slight apical bulge. The lateral sides of the hypotract are more or less straight and taper distally to the small antapical side which may be truncated with a small antapical horn on the left side. The cingulum is delimited by well defined ridges which bear strong spines. It is only slightly helicoidal and abuts against a wide sulcal region. The latter widens antapically to embrace the entire antapical ½side+; on the hypotract the sulcus is bordered by ridges. A few strong, thorn-like spines are present on the outer wall and are most concentrated along the plate boundaries of the pre- and postcingular series. A relatively thick walled inner body is always present and touches the outer wall only in the cingular region. The intercalary archaeopyle (2a) is of an elongate hexagonal outline; the operculum often remains attached at its precingular margin.
Original description: Davey and Verdier, 1973, p. 197
The spines on the outer wall are few in number and appear to be only tabular. They occasionally occur at the apical and antapical extremities of the cyst but are mostly confined to the plate boundaries perpendicular to the cingulum. Sometimes thickening of the outer wall occurs along these boundaries. Seven precingular and five postcingular plates appear to be deflned; cingular plates are not present. The inner body tends often to be transversely folded and a poorly developed excystment breakage always appears to be present in its apical region.
Affinities:
Davey and Verdier, 1973, p. 197: D. gallia is most similar to D. minor Cookson & Eisenack 1960 but differs in being more fusiform, having a stronger cingulum and, to a lesser extent, in other morphological features. D. echinoidea Cookson & Eisenack 1960 differs considerably from D. gallia in overall shape and spine cover. However, the specimen illustrated by Cookson & Eisenack (1960, pl. 1, fig. 6), as D. echinoidea, differs from the holotype of this species and appears to be a larger and more spiny form of D. gallia. Spinidinium vestitum Brideaux 1971 is larger, more spinous and apparently lacks an inner body. Deflandrea cf. echinoidea, as described by Davey 1970, is placed in synonymy with S. vestitum by Brideaux and on page 101 it is stated that Davey reported this species from Cenomanian of Saskatchewan. D. cf. echinoidea, however, was only recorded from England and the similar form D. echinoidea (Davey, 1970, p. 339, pl. 1, fig. 5) was reported only from Saskatchewan. It is only this latter form that may be synonymized with S. vestitum, although a well developed inner body is present. Finally, Deflandrea armata Cookson & Eisenack 1970 is another similar species, differing from D. gallia in being larger and having more numerous, broader spines.
Now Isabelidinium. Originally Deflandrea, subsequently Spinidinium, thirdly (and now) Isabelidinium.
Holotype: Davey and Verdier, 1973, pl.3, figs.1,3
Locus typicus: Saint Florentin, Chemin du CimentiÞre, France
Stratum typicum: Late Albian
Original diagnosis: Davey and Verdier, 1973, p. 196-197
This species of Deflandrea has an elongate pentagonal outline, the epitract being
longer than the hypotract, with a subspherical to ovoidal inner body. The sides of the epitract are moderately convex and there is a slight apical bulge. The lateral sides of the hypotract are more or less straight and taper distally to the small antapical side which may be truncated with a small antapical horn on the left side. The cingulum is delimited by well defined ridges which bear strong spines. It is only slightly helicoidal and abuts against a wide sulcal region. The latter widens antapically to embrace the entire antapical ½side+; on the hypotract the sulcus is bordered by ridges. A few strong, thorn-like spines are present on the outer wall and are most concentrated along the plate boundaries of the pre- and postcingular series. A relatively thick walled inner body is always present and touches the outer wall only in the cingular region. The intercalary archaeopyle (2a) is of an elongate hexagonal outline; the operculum often remains attached at its precingular margin.
Original description: Davey and Verdier, 1973, p. 197
The spines on the outer wall are few in number and appear to be only tabular. They occasionally occur at the apical and antapical extremities of the cyst but are mostly confined to the plate boundaries perpendicular to the cingulum. Sometimes thickening of the outer wall occurs along these boundaries. Seven precingular and five postcingular plates appear to be deflned; cingular plates are not present. The inner body tends often to be transversely folded and a poorly developed excystment breakage always appears to be present in its apical region.
Affinities:
Davey and Verdier, 1973, p. 197: D. gallia is most similar to D. minor Cookson & Eisenack 1960 but differs in being more fusiform, having a stronger cingulum and, to a lesser extent, in other morphological features. D. echinoidea Cookson & Eisenack 1960 differs considerably from D. gallia in overall shape and spine cover. However, the specimen illustrated by Cookson & Eisenack (1960, pl. 1, fig. 6), as D. echinoidea, differs from the holotype of this species and appears to be a larger and more spiny form of D. gallia. Spinidinium vestitum Brideaux 1971 is larger, more spinous and apparently lacks an inner body. Deflandrea cf. echinoidea, as described by Davey 1970, is placed in synonymy with S. vestitum by Brideaux and on page 101 it is stated that Davey reported this species from Cenomanian of Saskatchewan. D. cf. echinoidea, however, was only recorded from England and the similar form D. echinoidea (Davey, 1970, p. 339, pl. 1, fig. 5) was reported only from Saskatchewan. It is only this latter form that may be synonymized with S. vestitum, although a well developed inner body is present. Finally, Deflandrea armata Cookson & Eisenack 1970 is another similar species, differing from D. gallia in being larger and having more numerous, broader spines.