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Epiplosphaera gochtii
From Fensome et al., 2019:
Epiplosphaera gochtii (Fensome, 1979, p.20-22, pl.2, figs.8-9,11-12; text-fig.8) Brenner, 1988, p.51. Holotype: Fensome, 1979, pl.2, figs.8-9,11-12; text-fig.8. Originally Ellipsoidictyum, subsequently (and now) Epiplosphaera. Taxonomic junior synonym: Sentusidinium (as Epiplosphaera) ornata, according to Poulsen (1992a, p.68). Age: Early Callovian.
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Ellipsoidictyum gochtii sp. nov.
Plate 2, figs 8-9, 11-12; text-fig. 8
Gen. et sp. indet. 2 of Gocht, 1970, p. 152, pl. 34, figs 18-19; text-fig. 21.
Derivation of name: After Dr. Hans Gocht, micropalaeontologist at the University of Tübingen, West Germany.
Diagnosis: A species of Ellipsoidictyum with an ovoidal central body, from which arise numerous regularly distributed buccinate, capitate or bifurcate processes; these have a length equalling about one seventh of the breadth of the central body. The processes arise from low discontinuous crests which appear to represent the rudiments of a reticulum, although no enclosed fields are present. A laevorotatory paracingulum is clearly marked by parallel, almost continuous, crests. The parasulcus is marked on the ventral surface of the cyst by a zone almost free of crests. The cyst wall is single layered; the surface is regularly and densely pitted. The archeopyle is apical, polygonal and characterized by a moderately deep, broad parasulcal notch on its ventral margin.
Holotype: MGUH 14.687, 115.4/18.0; from GGU 100721, Fossilbjerget Member, Vardekløft Formation, west of Olympen. Plate 2, figs 8-9, 11-12; text-fig. 8.
Dimensions: Holotype; length of central body 42 μm, breadth of central body 35 μm, length of spines 4-6 μm. Range; (eight specimens) length of central body 42 (44) 48 μm, breadth of central body.35 (40) 49 μm, length of spines 3 (4.5) 6 μm.
Description: Ellipsoidictyum gochti possesses an ovoidal, dorso -ventrally compressed cyst. The cyst wall is single layered. It is ornamented by a fine honeycomb-like pattern of pits. More or less regularly distributed processes arise from a discontinuous network of low crests on the cyst surface. These processes are buccinate, capitate or symmetrically or asymmetrically bifurcate at their distal ends. They are usually solid, though small cavities may be present at their base, or elsewhere along their length; they are distally closed. The processes vary in length by about 2 μm on a single specimen and also vary in thickness. One process on the holotype is exceptionally broad and hollow, but such processes are rare (Gocht [1970, text-fig. 21] also illustrates one exceptionally broad process in his figured specimen). The paracingulum is clearly defined by two parallel crests which are partly disrupted but more continuous than any crests elsewhere on the cyst. In all of the specimens encountered, crests occurred only rarely within the paracingulum. The paracingulum is laevorotatory, its two ends being offset at the parasulcus by a
distance equal to one paracingulum width. The parasulcus is also readily perceived; it is indicated by a broad parasulcal notch on the archeopyle margin, displacement of the paracingulum and a relative absence of crests within or crossing it. However, its margins are not delineated by crests for most of their length. The crests on the cyst surtace appear to give some indication of a gonyaulacoid paratabulation. The archeopyle is apical, the operculum being detached in all specimens encountered. It is polygonal in outline but not deeply notched except at the parasulcus.
Remarks: This species is clearly attributable to the genus Ellipsoidictyum because of its apical archeopyle, its pattern of crests and processes, its clearly defined furrows, the indistinct indication of a paratabulation, and its ovoidal shape. It differs from E. cinctum Klement, 1960 and E. reticulatum (Valensi, 1953) in the discontinuous nature of its crests, and from E. cinctum additionally in its possession of numerous processes arising from its crests. Its finely pitted surface ornament is also characteristic.
Gocht (1970) described a very similar form which he called Gen. et sp. indet. 2. Apart from the presence of some simple processes and, at least in his figured specimen, slightly less well defined furrows, Gocht's specimens and those from Jameson Land are morphologically very similar; indeed they are almost certainly representatives of the same species.
Epiplosphaera gochtii (Fensome, 1979, p.20-22, pl.2, figs.8-9,11-12; text-fig.8) Brenner, 1988, p.51. Holotype: Fensome, 1979, pl.2, figs.8-9,11-12; text-fig.8. Originally Ellipsoidictyum, subsequently (and now) Epiplosphaera. Taxonomic junior synonym: Sentusidinium (as Epiplosphaera) ornata, according to Poulsen (1992a, p.68). Age: Early Callovian.
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Ellipsoidictyum gochtii sp. nov.
Plate 2, figs 8-9, 11-12; text-fig. 8
Gen. et sp. indet. 2 of Gocht, 1970, p. 152, pl. 34, figs 18-19; text-fig. 21.
Derivation of name: After Dr. Hans Gocht, micropalaeontologist at the University of Tübingen, West Germany.
Diagnosis: A species of Ellipsoidictyum with an ovoidal central body, from which arise numerous regularly distributed buccinate, capitate or bifurcate processes; these have a length equalling about one seventh of the breadth of the central body. The processes arise from low discontinuous crests which appear to represent the rudiments of a reticulum, although no enclosed fields are present. A laevorotatory paracingulum is clearly marked by parallel, almost continuous, crests. The parasulcus is marked on the ventral surface of the cyst by a zone almost free of crests. The cyst wall is single layered; the surface is regularly and densely pitted. The archeopyle is apical, polygonal and characterized by a moderately deep, broad parasulcal notch on its ventral margin.
Holotype: MGUH 14.687, 115.4/18.0; from GGU 100721, Fossilbjerget Member, Vardekløft Formation, west of Olympen. Plate 2, figs 8-9, 11-12; text-fig. 8.
Dimensions: Holotype; length of central body 42 μm, breadth of central body 35 μm, length of spines 4-6 μm. Range; (eight specimens) length of central body 42 (44) 48 μm, breadth of central body.35 (40) 49 μm, length of spines 3 (4.5) 6 μm.
Description: Ellipsoidictyum gochti possesses an ovoidal, dorso -ventrally compressed cyst. The cyst wall is single layered. It is ornamented by a fine honeycomb-like pattern of pits. More or less regularly distributed processes arise from a discontinuous network of low crests on the cyst surface. These processes are buccinate, capitate or symmetrically or asymmetrically bifurcate at their distal ends. They are usually solid, though small cavities may be present at their base, or elsewhere along their length; they are distally closed. The processes vary in length by about 2 μm on a single specimen and also vary in thickness. One process on the holotype is exceptionally broad and hollow, but such processes are rare (Gocht [1970, text-fig. 21] also illustrates one exceptionally broad process in his figured specimen). The paracingulum is clearly defined by two parallel crests which are partly disrupted but more continuous than any crests elsewhere on the cyst. In all of the specimens encountered, crests occurred only rarely within the paracingulum. The paracingulum is laevorotatory, its two ends being offset at the parasulcus by a
distance equal to one paracingulum width. The parasulcus is also readily perceived; it is indicated by a broad parasulcal notch on the archeopyle margin, displacement of the paracingulum and a relative absence of crests within or crossing it. However, its margins are not delineated by crests for most of their length. The crests on the cyst surtace appear to give some indication of a gonyaulacoid paratabulation. The archeopyle is apical, the operculum being detached in all specimens encountered. It is polygonal in outline but not deeply notched except at the parasulcus.
Remarks: This species is clearly attributable to the genus Ellipsoidictyum because of its apical archeopyle, its pattern of crests and processes, its clearly defined furrows, the indistinct indication of a paratabulation, and its ovoidal shape. It differs from E. cinctum Klement, 1960 and E. reticulatum (Valensi, 1953) in the discontinuous nature of its crests, and from E. cinctum additionally in its possession of numerous processes arising from its crests. Its finely pitted surface ornament is also characteristic.
Gocht (1970) described a very similar form which he called Gen. et sp. indet. 2. Apart from the presence of some simple processes and, at least in his figured specimen, slightly less well defined furrows, Gocht's specimens and those from Jameson Land are morphologically very similar; indeed they are almost certainly representatives of the same species.