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Ellipsoidictyum
From Williams et al., 2017:
[Ellipsoidictyum, Klement, 1960, p.78
Tax. jr. syn.: Dictyopyxis Cookson and Eisenack and Dictyopyxidia, both according to Sarjeant (1976a, p.23); Opaeopsomus, according to Stover and Evitt (1978, p.69) — however, Lentin and Williams (1993, p.465) retained Opaeopsomus.
Type species: Ellipsoidictyum cinctum, Klement, 1960 (pl.6, figs.15–16)]
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Original description: [Klement 1960]: (Translation: Stover and Evitt, 1978, p.43)
Diagnosis:
Shell with an irregular reticulate structure, formed by undulating narrow superimposed lamellae. Clear indication of a spiral trending girdle by means of a band-forming arrangement of elongated rectangular meshes of this network. Similar indication of a longitudinal furrow area. By this means dorso-ventral orientation possible. Continuous narrow linking selvage connects equally long peripheral processes.
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Modified description:
Stover and Evitt 1978, p. 43:
Synopsis:
Cysts proximochorate, subspherical to elongate ellipsoidal; autophragm with curved to straight interconnected septa forming an irregular reticulum; lumina of various shapes and sizes; some septa may be parasutural; archaeopyle apical, probably type tA.
Description:
Shape: Subspherical to elongate ellipsoidal; outline occasionally somewhat roundly polygonal.
Wall relationships: Autophragm only.
Wall features: Some septa are parasutural; however, it is often difficult to separate parasutural from non-parasutural septa on forms with fine-meshed reticula. On specimens with coarse-meshed reticula, most septa are parasutural and at least some of the paratabulation is decipherable. Autophragm between septa smooth or with features of low relief.
Paratabulation: Commonly expressed by the archaeopyle and paracingulum, less commonly by parasutural features; paratabulation on hypocyst rarely, if ever, clearly indicated; formula unknown.
Archaeopyle: Apical, probably type tA; opeculum normally free.
Paracingulum: Generally clearly indicated by parallel, transverse, parasutural septa connected longitudinally by a few to 10 or more septa.
Parasulcus: Position indicated by an area without septa or with only a few septa.
Size: Small to large.
Affinities:
Ellipsoidictyum differs from Cassiculosphaeridia in having indications of paratabulation other than the archaeopyle, and in being generally more elongate longitudinally. In addition, the apical archaeopyle on Ellipsoidictyum tends to have a decided angular outline, whereas on Cassiculosphaeridia it tends to be circular or nearly so.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Ellipsoidicytum Klement, 1960. According to Feist-Burkhardt and Monteil (1997), Epiplosphaera differs form Ellipsoidictyum and Valensiella in the presence of processes on the crests. Poulsen (1992, p.66) stated that Epiplosphaera differs form Ellipsoidictyum in having spines which are interconnected (by) muri or septa that are typically uneven distally. Ellipsoidictyum lacks spines and has muri that are essentially uniform in height so that the outline of the cyst is fairly smooth, not irregular and jagged as in Epiplosphaera.
[Ellipsoidictyum, Klement, 1960, p.78
Tax. jr. syn.: Dictyopyxis Cookson and Eisenack and Dictyopyxidia, both according to Sarjeant (1976a, p.23); Opaeopsomus, according to Stover and Evitt (1978, p.69) — however, Lentin and Williams (1993, p.465) retained Opaeopsomus.
Type species: Ellipsoidictyum cinctum, Klement, 1960 (pl.6, figs.15–16)]
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Original description: [Klement 1960]: (Translation: Stover and Evitt, 1978, p.43)
Diagnosis:
Shell with an irregular reticulate structure, formed by undulating narrow superimposed lamellae. Clear indication of a spiral trending girdle by means of a band-forming arrangement of elongated rectangular meshes of this network. Similar indication of a longitudinal furrow area. By this means dorso-ventral orientation possible. Continuous narrow linking selvage connects equally long peripheral processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 43:
Synopsis:
Cysts proximochorate, subspherical to elongate ellipsoidal; autophragm with curved to straight interconnected septa forming an irregular reticulum; lumina of various shapes and sizes; some septa may be parasutural; archaeopyle apical, probably type tA.
Description:
Shape: Subspherical to elongate ellipsoidal; outline occasionally somewhat roundly polygonal.
Wall relationships: Autophragm only.
Wall features: Some septa are parasutural; however, it is often difficult to separate parasutural from non-parasutural septa on forms with fine-meshed reticula. On specimens with coarse-meshed reticula, most septa are parasutural and at least some of the paratabulation is decipherable. Autophragm between septa smooth or with features of low relief.
Paratabulation: Commonly expressed by the archaeopyle and paracingulum, less commonly by parasutural features; paratabulation on hypocyst rarely, if ever, clearly indicated; formula unknown.
Archaeopyle: Apical, probably type tA; opeculum normally free.
Paracingulum: Generally clearly indicated by parallel, transverse, parasutural septa connected longitudinally by a few to 10 or more septa.
Parasulcus: Position indicated by an area without septa or with only a few septa.
Size: Small to large.
Affinities:
Ellipsoidictyum differs from Cassiculosphaeridia in having indications of paratabulation other than the archaeopyle, and in being generally more elongate longitudinally. In addition, the apical archaeopyle on Ellipsoidictyum tends to have a decided angular outline, whereas on Cassiculosphaeridia it tends to be circular or nearly so.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Ellipsoidicytum Klement, 1960. According to Feist-Burkhardt and Monteil (1997), Epiplosphaera differs form Ellipsoidictyum and Valensiella in the presence of processes on the crests. Poulsen (1992, p.66) stated that Epiplosphaera differs form Ellipsoidictyum in having spines which are interconnected (by) muri or septa that are typically uneven distally. Ellipsoidictyum lacks spines and has muri that are essentially uniform in height so that the outline of the cyst is fairly smooth, not irregular and jagged as in Epiplosphaera.