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Epiplosphaera areolata
Epiplosphaera areolata Klement, 1960
Originally (and now) Epiplosphaera, subsequently Lithodinia?.
Sarjeant, 1984, provisionally transferred this species to Lithodinia Eisenack, 1935. Brenner, 1988, retained it in Epiplosphaera.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Epiplosphaera areolata Klement, 1960, has a fine-meshed, irregular reticulum . Short simple processes arise from the junctions and are basally connected. Length 55-83 µm, processes up to 12 µm.
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Holotype: Klement, 1960, pl.8, fig.5-7
Paratypes: Klement, 1960
Locus typicus: Borehole Scherstetten 1 Well, SW Germany
Stratum typicum: Malm Gamma 3 (Similis-beds), Early Kimmeridgian
Translation diagnosis Klement, 1960, Courtinat, 1989: LPP
Translation description Klement 1960: GSC
Diagnosis: Klement, 1960, p. 76
A species of the genus Epiplosphaera with ellipsoidal shell, of which the surface is fine-meshed and irregularly polygonal. Simple, short, thorn-like processes in linear arrangement on junctions of the basal network, rarely isolated, as a rule mutually connected by narrow bulges. These connections run, corresponding to process distribution, in a lineaar fashion in longitudinal and transversal directions, resulting in an areolation on the shell in the form of trapezoidal, joining structures on epi- and hypovalve.
Dimensions:
Holotype: L:B with processes 66:63 Ám, L:B without processes 52:49 Ám, process length 9-12 Ám.
Paratypes: L:B with processes 72:66 and 66:61 Ám, L:B without processes 52:49 and 52:49 Ám, process length 12-15 and about 9 Ám.
Diameter in polar view: L:B without processes: 50 Ám, process length 10 Ám.
Minimum: L:B with processes 60:55 Ám, L:B without processes 46:43 Ám, process length 7-8 Ám.
Maximum: L:B with processes 83:79 Ám, L:B without processes 63:57 Ám, process length 11-12 Ám.
Original description: Klement 1960, p. 76: Epiplosphaera areolata
This species was found extremely frequently in the present material, to which we should add that, for the major part, it was found in an extremely well preserved three-dimensional state.
The ellipsoidal, very thin-walled shells display on their surface a fine, small-meshed network structure in form of an internal, reticular membrane-differentiation, the thickness of which can vary. It is for this reason, that next to specimens with distinct network structures, we also find those in which this type of ornamentation can be recognized only in certain places, and that finally we can find organisms in which no membranous reticulation whatsoever can be recognized. However, these last mentioned types of organisms posses a general overall habitus which agress so extensively with the other ones, so that thay can be placed without any qualms with said other organsims, this the more so, since a transition range with less distinct, but nevertheless unequivocally definable structures is also present.
From one portion of the junction points of the network, simple short processes arise in a regular linear pattern, whereby said processes are partially spine-like and stiff and partially bent to a certain degree; the broadened basal regions of the processes blend into the connecting lists. The processes stand seldom isolated, and as a rule are connected at their bases by means of low bulge-like lists following a straight-lined course. Generally speaking, these lists extend from one pole to the other or perpendicular to that direction; this results therein, that in the ideal case, one row each of parallel arranged, trapezium-shaped areolas borderingagainst one another, are formed on the epivalva and on the hypovalva. However, in part, only more or less irregularly distributed, wide-meshed structures occur, and in some cases we only find a few closed formations.
A large number of the specimens showed an apex/antapex-orientation in the preparation, whereby a regularly shaped circular cross-section of the shell could be observed.
In a predominant number of cases, one pole of the shell was always split-off in a calotte-like manner. Due to the absolute regularity of this occurence, this phenomenon must be interpreted as a pylome formatation.
The very thin-walled shell membrane ranges from a light yellow to a dark brown coloration, whereas the connecting bulge-like lists of the processes are always of a somewhat darker coloration.
Relationships: This species can be distinctly separated from the E. bireticulata by the absence of the sutural network on the shell surface, which is characteristic for the E. bireticulata. In comparison to the E.reticulospinosa, the following features offer precise differential-diagnostic criteria namely, on the one hand, the E.areoalta's additional, bulge-shaped, linear basal intergrowths whixh form regular, closed structures and, on the other hand, the absence of the type of sutures which are characteristic for said E.reticulspinosa and show up, especially, between the merginal processes.
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Courtinat, 1989, p.176
Remark: The reallocation Lithodinia? areolata proposed by Sarjeant is not retained. E. areolata presents crests bearing processes, with a particular arrangement, in any case not corresponding to the crest arrangement in the genus Lithodinia
Eisenack emend. Gocht 1975. The crests in E. areolata are penitabular, on the edges of the paraplates of the apical- precingular and antapical-postcingular series. The crests of two adjacent paraplates rejoin longitudinally and form only a sutural crest. In the epicystal region, no process occurs in an intratabular position; the postcingular paraplates however show a process, each in an intratabular position.
Originally (and now) Epiplosphaera, subsequently Lithodinia?.
Sarjeant, 1984, provisionally transferred this species to Lithodinia Eisenack, 1935. Brenner, 1988, retained it in Epiplosphaera.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Epiplosphaera areolata Klement, 1960, has a fine-meshed, irregular reticulum . Short simple processes arise from the junctions and are basally connected. Length 55-83 µm, processes up to 12 µm.
--------------------------------------------------
Holotype: Klement, 1960, pl.8, fig.5-7
Paratypes: Klement, 1960
Locus typicus: Borehole Scherstetten 1 Well, SW Germany
Stratum typicum: Malm Gamma 3 (Similis-beds), Early Kimmeridgian
Translation diagnosis Klement, 1960, Courtinat, 1989: LPP
Translation description Klement 1960: GSC
Diagnosis: Klement, 1960, p. 76
A species of the genus Epiplosphaera with ellipsoidal shell, of which the surface is fine-meshed and irregularly polygonal. Simple, short, thorn-like processes in linear arrangement on junctions of the basal network, rarely isolated, as a rule mutually connected by narrow bulges. These connections run, corresponding to process distribution, in a lineaar fashion in longitudinal and transversal directions, resulting in an areolation on the shell in the form of trapezoidal, joining structures on epi- and hypovalve.
Dimensions:
Holotype: L:B with processes 66:63 Ám, L:B without processes 52:49 Ám, process length 9-12 Ám.
Paratypes: L:B with processes 72:66 and 66:61 Ám, L:B without processes 52:49 and 52:49 Ám, process length 12-15 and about 9 Ám.
Diameter in polar view: L:B without processes: 50 Ám, process length 10 Ám.
Minimum: L:B with processes 60:55 Ám, L:B without processes 46:43 Ám, process length 7-8 Ám.
Maximum: L:B with processes 83:79 Ám, L:B without processes 63:57 Ám, process length 11-12 Ám.
Original description: Klement 1960, p. 76: Epiplosphaera areolata
This species was found extremely frequently in the present material, to which we should add that, for the major part, it was found in an extremely well preserved three-dimensional state.
The ellipsoidal, very thin-walled shells display on their surface a fine, small-meshed network structure in form of an internal, reticular membrane-differentiation, the thickness of which can vary. It is for this reason, that next to specimens with distinct network structures, we also find those in which this type of ornamentation can be recognized only in certain places, and that finally we can find organisms in which no membranous reticulation whatsoever can be recognized. However, these last mentioned types of organisms posses a general overall habitus which agress so extensively with the other ones, so that thay can be placed without any qualms with said other organsims, this the more so, since a transition range with less distinct, but nevertheless unequivocally definable structures is also present.
From one portion of the junction points of the network, simple short processes arise in a regular linear pattern, whereby said processes are partially spine-like and stiff and partially bent to a certain degree; the broadened basal regions of the processes blend into the connecting lists. The processes stand seldom isolated, and as a rule are connected at their bases by means of low bulge-like lists following a straight-lined course. Generally speaking, these lists extend from one pole to the other or perpendicular to that direction; this results therein, that in the ideal case, one row each of parallel arranged, trapezium-shaped areolas borderingagainst one another, are formed on the epivalva and on the hypovalva. However, in part, only more or less irregularly distributed, wide-meshed structures occur, and in some cases we only find a few closed formations.
A large number of the specimens showed an apex/antapex-orientation in the preparation, whereby a regularly shaped circular cross-section of the shell could be observed.
In a predominant number of cases, one pole of the shell was always split-off in a calotte-like manner. Due to the absolute regularity of this occurence, this phenomenon must be interpreted as a pylome formatation.
The very thin-walled shell membrane ranges from a light yellow to a dark brown coloration, whereas the connecting bulge-like lists of the processes are always of a somewhat darker coloration.
Relationships: This species can be distinctly separated from the E. bireticulata by the absence of the sutural network on the shell surface, which is characteristic for the E. bireticulata. In comparison to the E.reticulospinosa, the following features offer precise differential-diagnostic criteria namely, on the one hand, the E.areoalta's additional, bulge-shaped, linear basal intergrowths whixh form regular, closed structures and, on the other hand, the absence of the type of sutures which are characteristic for said E.reticulspinosa and show up, especially, between the merginal processes.
---------------------------------------------------------
Courtinat, 1989, p.176
Remark: The reallocation Lithodinia? areolata proposed by Sarjeant is not retained. E. areolata presents crests bearing processes, with a particular arrangement, in any case not corresponding to the crest arrangement in the genus Lithodinia
Eisenack emend. Gocht 1975. The crests in E. areolata are penitabular, on the edges of the paraplates of the apical- precingular and antapical-postcingular series. The crests of two adjacent paraplates rejoin longitudinally and form only a sutural crest. In the epicystal region, no process occurs in an intratabular position; the postcingular paraplates however show a process, each in an intratabular position.