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Epiplosphaera reticulata
From Fensome et al., 2019:
Epiplosphaera reticulata (Valensi, 1953, p.28, pl.2, figs.4–5,14,19; pl.13, fig.6; text-fig.2d ex Sarjeant, 1968, p.230) Courtinat, 1989, p.176. Holotype: Valensi, 1953, pl.2, figs.4–5; Fauconnier and Masure, 2004, pl.28, figs.1–4. Originally Palaeoperidinium (name not validly published), subsequently Dictyopyxis (generic name illegitimate), thirdly Dictyopyxidia, fourthly Ellipsoidictyum, fifthly (and now) Epiplosphaera. Taxonomic senior synonym: Epiplosphaera bireticulata, by implication in Courtinat (1989, p.176), who believed Palaeoperidinium (as Epiplosphaera) reticulatum to be the senior name — however, Poulsen (1992a, p.66) retained the two species. Age: Bajocian.
Translation Courtinat, 1989: LPP
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Original description: [Valensi, 1953] (translated from French):
Palaeoperidinium reticulatum nov. sp.
PI. I, figs. 4, 5, 14, 19 and XIII, ig. 6; text-fig. 2 d.
HOLOTYPE: Bajocian, flint from the Cinglais Forest (Calvados) (BS 27).
PARATYPE: Bathonian, Lessart flint.
The round or ovoid shell is covered with a network of dark lines delimiting polygonal fields;
this network bears spines with swollen bases on its nodes and between them, the generally bifurcated ends of which are extended by two, three, or four flaments, which anastomose with those of neighboring spines and thus form a second, fine and difficult-to-see network. This second network overlaps the first;
sometimes completely covering it (fig. 2 d). The whole, as complicated as it is difficult to interpret, presents
in all cases the characteristic appearance of spiny branches intertwined with solitary twigs.
On the edge of the shell, the spines appear as processes with forked or T-shaped ends; the superposition of their filaments gives the illusion of a continuous line concentric with the shell.
The dorsal surface of the holotype shows a very clear transverse groove; its more damaged ventral surface (PI. 1, fig. 5) appears to possess a longitudinal groove. In the other specimens, the grooves are much less clear, and their identification is complicated by the fact that the lines of the network are often parallel and appear to limit false grooves. Sometimes one end of the shell has an opening. The dimensions of the holotype, including the spines, are 48 μ in length and 42 μ in width;
those of the other specimens vary from 45 to 52 μ with the spines, which are about 3 u long.
The color of the shell is dark brown.
Palaeoperidinium reticulatum is common in the Bathonian around Poitiers. The flints
from Lessart and Mouchedune provided me with about thirty specimens similar to the paratype
in Pl. II, Fig. 14, four of which are grouped together in the field of a x10 objective. It is present in the Bathonian of Moulinet and Vouillé, in the Bajocian of the Cinglais Forest, and the Vesulian around Caen: it appears to be localized in the Bathonian.
It does not resemble any other Palaeoperidinium described so far; On the other hand, it often resembles
Membranilarnax ovulum or Hystrichosphaeridium pattei; discrimination is easy in the presence of a groove, difficult in its absence. It differs from the former by the absence of an external film and from the latter by its tighter network and anastomosing filaments.
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Courtinat, 1989, p.176
Remark: Palaeoperidinium reticulatum and Epiplosphaera bireticulata (type species of the genus Epiplosphaera) are placed in synonymy because the diagnosis given by Valensi (1953) for P. reticulatum is very plain and corresponds exactly to that of E. bireticulata.
Epiplosphaera reticulata (Valensi, 1953, p.28, pl.2, figs.4–5,14,19; pl.13, fig.6; text-fig.2d ex Sarjeant, 1968, p.230) Courtinat, 1989, p.176. Holotype: Valensi, 1953, pl.2, figs.4–5; Fauconnier and Masure, 2004, pl.28, figs.1–4. Originally Palaeoperidinium (name not validly published), subsequently Dictyopyxis (generic name illegitimate), thirdly Dictyopyxidia, fourthly Ellipsoidictyum, fifthly (and now) Epiplosphaera. Taxonomic senior synonym: Epiplosphaera bireticulata, by implication in Courtinat (1989, p.176), who believed Palaeoperidinium (as Epiplosphaera) reticulatum to be the senior name — however, Poulsen (1992a, p.66) retained the two species. Age: Bajocian.
Translation Courtinat, 1989: LPP
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Original description: [Valensi, 1953] (translated from French):
Palaeoperidinium reticulatum nov. sp.
PI. I, figs. 4, 5, 14, 19 and XIII, ig. 6; text-fig. 2 d.
HOLOTYPE: Bajocian, flint from the Cinglais Forest (Calvados) (BS 27).
PARATYPE: Bathonian, Lessart flint.
The round or ovoid shell is covered with a network of dark lines delimiting polygonal fields;
this network bears spines with swollen bases on its nodes and between them, the generally bifurcated ends of which are extended by two, three, or four flaments, which anastomose with those of neighboring spines and thus form a second, fine and difficult-to-see network. This second network overlaps the first;
sometimes completely covering it (fig. 2 d). The whole, as complicated as it is difficult to interpret, presents
in all cases the characteristic appearance of spiny branches intertwined with solitary twigs.
On the edge of the shell, the spines appear as processes with forked or T-shaped ends; the superposition of their filaments gives the illusion of a continuous line concentric with the shell.
The dorsal surface of the holotype shows a very clear transverse groove; its more damaged ventral surface (PI. 1, fig. 5) appears to possess a longitudinal groove. In the other specimens, the grooves are much less clear, and their identification is complicated by the fact that the lines of the network are often parallel and appear to limit false grooves. Sometimes one end of the shell has an opening. The dimensions of the holotype, including the spines, are 48 μ in length and 42 μ in width;
those of the other specimens vary from 45 to 52 μ with the spines, which are about 3 u long.
The color of the shell is dark brown.
Palaeoperidinium reticulatum is common in the Bathonian around Poitiers. The flints
from Lessart and Mouchedune provided me with about thirty specimens similar to the paratype
in Pl. II, Fig. 14, four of which are grouped together in the field of a x10 objective. It is present in the Bathonian of Moulinet and Vouillé, in the Bajocian of the Cinglais Forest, and the Vesulian around Caen: it appears to be localized in the Bathonian.
It does not resemble any other Palaeoperidinium described so far; On the other hand, it often resembles
Membranilarnax ovulum or Hystrichosphaeridium pattei; discrimination is easy in the presence of a groove, difficult in its absence. It differs from the former by the absence of an external film and from the latter by its tighter network and anastomosing filaments.
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Courtinat, 1989, p.176
Remark: Palaeoperidinium reticulatum and Epiplosphaera bireticulata (type species of the genus Epiplosphaera) are placed in synonymy because the diagnosis given by Valensi (1953) for P. reticulatum is very plain and corresponds exactly to that of E. bireticulata.