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Diphasiosphaera
From Williams et al., 2017:
[Diphasiosphaera, Duxbury, 1980, p. 115-116
tax. jr. synonym of Hystrichostrogylon Agelopoulos, 1964, according to Stover and Williams, 1987. Sarjeant in Lentin and Williams, 1989, considered that the disproportionally small size of the central body and the consistent presence of an apical horn in Diphasiosphaera distinguish it as a separate genus.
Type species: Diphasiosphaera stolidota, Duxbury, 1980 (pl.1, fig.5; text-fig.6)]
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Original description: [Duxbury, 1980]:
Description:
Dinoflagellate cysts which are cavate and distinctly bi-layered. Both endoblast and periblast are spheroidal and the latter bears a prominent apical
protuberance. The archeopyle is single-paraplate precingular (3") and the body layers are in contact only around and posterior to the archeopyle margin. Vague paratabulation, which appears gonyaulacacean, is outlined on the periblast by largely degenerate gonal and parasutural processes, with or without proximal connecting ridges. The ventral periblast displays a large hole in a parasulcal position.
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Stover and Williams, 1987, p. 81:
Affinities:
The circumscription of Diphasiosphaera contains all the essential features, given by Stover and Evitt 1978, for Hystrichostrogylon. The processes on the illustrations of D. stolidota, the type species of Diphasiosphaera, appear truncate, rather than distally bifurcate or trifurcate as they are on Hystrichostrogylon. However, Duxbury stated (1980, p. 117) that . . ."The parasutural processes, at their fullest development, are similar to those of some species of Spiniferites Mantell, 1850 emend.
Sarjeant, 1970. Reduction of processes in the more cavate regions involves firstly the loss of process `stalks` so that one may see double rows of spines marking out paraplate boundaries with these spines representing the distal bifurcation of parasutural processes" Since the basic morphology of Diphasiosphaera and Hystrichostrogylon is essentially identical and each possesses processes of the Spiniferites type, the two forms are considered as congeneric, with Diphasiosphaera being the junior synonym.
[Diphasiosphaera, Duxbury, 1980, p. 115-116
tax. jr. synonym of Hystrichostrogylon Agelopoulos, 1964, according to Stover and Williams, 1987. Sarjeant in Lentin and Williams, 1989, considered that the disproportionally small size of the central body and the consistent presence of an apical horn in Diphasiosphaera distinguish it as a separate genus.
Type species: Diphasiosphaera stolidota, Duxbury, 1980 (pl.1, fig.5; text-fig.6)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Duxbury, 1980]:
Description:
Dinoflagellate cysts which are cavate and distinctly bi-layered. Both endoblast and periblast are spheroidal and the latter bears a prominent apical
protuberance. The archeopyle is single-paraplate precingular (3") and the body layers are in contact only around and posterior to the archeopyle margin. Vague paratabulation, which appears gonyaulacacean, is outlined on the periblast by largely degenerate gonal and parasutural processes, with or without proximal connecting ridges. The ventral periblast displays a large hole in a parasulcal position.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Stover and Williams, 1987, p. 81:
Affinities:
The circumscription of Diphasiosphaera contains all the essential features, given by Stover and Evitt 1978, for Hystrichostrogylon. The processes on the illustrations of D. stolidota, the type species of Diphasiosphaera, appear truncate, rather than distally bifurcate or trifurcate as they are on Hystrichostrogylon. However, Duxbury stated (1980, p. 117) that . . ."The parasutural processes, at their fullest development, are similar to those of some species of Spiniferites Mantell, 1850 emend.
Sarjeant, 1970. Reduction of processes in the more cavate regions involves firstly the loss of process `stalks` so that one may see double rows of spines marking out paraplate boundaries with these spines representing the distal bifurcation of parasutural processes" Since the basic morphology of Diphasiosphaera and Hystrichostrogylon is essentially identical and each possesses processes of the Spiniferites type, the two forms are considered as congeneric, with Diphasiosphaera being the junior synonym.