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Hafniasphaera
From Williams et al., 2017:
[Hafniasphaera, Hansen, 1977, p. 13-14; Emendation: Fensome et al., 2009, p. 34.
Tax. sen. syn.: Spiniferites, according to Stover and Williams (1987, p.117) — however, Edwards (1996, p.989) retained Hafniasphaera.
Tax. sen. syn.: Rivernookia, according to Lentin and Williams (1985, p.311). Fensome et al. (2009, p.34) retained Hafniasphaera at generic rank.
Type species: Hafniasphaera hyalospinosa, Hansen, 1977 (fig.18A)]
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Original description: [Hansen, 1977]:
Description:
Chorate cysts with a subspherical or ovoid central body composed of two layers, endophragm and periphragm. One or both of these layers contain numerous evenly distributed vesicles (vacuoles). The vesicles are spherical or, if interconnected, they may form a fine reticulum internal in the cyst wall.
Processes intratabular, formed by the periphragm, with or without vesicles, solid or hollow, closed or open distally. Simple processes trifurcate (gonal processes) or bifurcate (sutural processes). Composite processes ramifying in more complex ways. Tips of furcae bifid.
Archaeopyle type P, formed by loss of paraplate 3". Operculum becomes typically completely detached.
Paratabulation indicated by presence of sutural crests, weak bulges of the periphragm, by alignment of the vesicles, or by the arrangement of the processes only. Paratabulation of plates 1`-3`(4`),1"- 6", 1 c-6c, (1```) 2```-6```, (ps), (1 p), 1````. Paraplate 6" is triangular, 1``` very little if not absent. If present paraplate 4` is situated between 1" and 5", above 6" and parasulcus. Suture between 3``` and 4``` is situated a little to the left of suture between 2" and 3", whereas suture between 4``` and 5``` is aligned with or slightly to the right of suture between 3" and 4". Paracingulum disposed in a laevorotary spiral.
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Emended description:
Fensome et al., 2009:
Diagnosis:
Gonyaulacoid cysts, chorate to proximochorate with a spheroidal to subovoidal central body. Acavate. Generally paratabulate, with Spiniferites-like gonal and sutural processes that are vesiculate; the central body wall may or may not be vesiculate. Archaeopyle precingular, with formula P3", operculum free.
Remarks:
The above emended diagnosis can also serve as a synopsis. We here restrict Hafniasphaera to forms like Spiniferites but with vesiculate processes. In proposing this genus, Hansen (1977) provided a long 'diagnosis' (in essence a description), but no true diagnosis or differentiation. In the description, he specified that the wall of the central body is vesiculate and that the processes may or may not be vesiculate. From general observations, it seems to us that various Spiniferites morphotypes throughout the range of that genus can develop variants with a vesiculate central body wall: for example, Hafniasphaera graciosa may be a vesiculate development of the Spiniferites pseudo for catus morphotype. In contrast, a focus on vesiculation of the processes (with or without a vesiculate central body wall) seems to separate from Spiniferites a group of forms that have a range mainly within the later Cretaceous and earlier Palaeogene: it is this group that we assign to Hafniasphaera. Quattrocchio & Sarjeant's (2003) proposal to consider Hafniasphaera a subgenus of Spiniferites may have some theoretical merit, but is pragmatically awkward and tends to mask the usefulness of this taxon. Hence we prefer to maintain Hafniasphaera as a separate genus.
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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.
Hafniasphaera Hansen, 1977, is a Spiniferites with a vesicular or vacuolate wall. It has gonal and sutural processes and a P(3") archeopyle. This particular vacuolate wall appears to have a restricted stratigraphic occurrence primarily in the Paleocene, but also in the Eocene.
[Hafniasphaera, Hansen, 1977, p. 13-14; Emendation: Fensome et al., 2009, p. 34.
Tax. sen. syn.: Spiniferites, according to Stover and Williams (1987, p.117) — however, Edwards (1996, p.989) retained Hafniasphaera.
Tax. sen. syn.: Rivernookia, according to Lentin and Williams (1985, p.311). Fensome et al. (2009, p.34) retained Hafniasphaera at generic rank.
Type species: Hafniasphaera hyalospinosa, Hansen, 1977 (fig.18A)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Hansen, 1977]:
Description:
Chorate cysts with a subspherical or ovoid central body composed of two layers, endophragm and periphragm. One or both of these layers contain numerous evenly distributed vesicles (vacuoles). The vesicles are spherical or, if interconnected, they may form a fine reticulum internal in the cyst wall.
Processes intratabular, formed by the periphragm, with or without vesicles, solid or hollow, closed or open distally. Simple processes trifurcate (gonal processes) or bifurcate (sutural processes). Composite processes ramifying in more complex ways. Tips of furcae bifid.
Archaeopyle type P, formed by loss of paraplate 3". Operculum becomes typically completely detached.
Paratabulation indicated by presence of sutural crests, weak bulges of the periphragm, by alignment of the vesicles, or by the arrangement of the processes only. Paratabulation of plates 1`-3`(4`),1"- 6", 1 c-6c, (1```) 2```-6```, (ps), (1 p), 1````. Paraplate 6" is triangular, 1``` very little if not absent. If present paraplate 4` is situated between 1" and 5", above 6" and parasulcus. Suture between 3``` and 4``` is situated a little to the left of suture between 2" and 3", whereas suture between 4``` and 5``` is aligned with or slightly to the right of suture between 3" and 4". Paracingulum disposed in a laevorotary spiral.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Fensome et al., 2009:
Diagnosis:
Gonyaulacoid cysts, chorate to proximochorate with a spheroidal to subovoidal central body. Acavate. Generally paratabulate, with Spiniferites-like gonal and sutural processes that are vesiculate; the central body wall may or may not be vesiculate. Archaeopyle precingular, with formula P3", operculum free.
Remarks:
The above emended diagnosis can also serve as a synopsis. We here restrict Hafniasphaera to forms like Spiniferites but with vesiculate processes. In proposing this genus, Hansen (1977) provided a long 'diagnosis' (in essence a description), but no true diagnosis or differentiation. In the description, he specified that the wall of the central body is vesiculate and that the processes may or may not be vesiculate. From general observations, it seems to us that various Spiniferites morphotypes throughout the range of that genus can develop variants with a vesiculate central body wall: for example, Hafniasphaera graciosa may be a vesiculate development of the Spiniferites pseudo for catus morphotype. In contrast, a focus on vesiculation of the processes (with or without a vesiculate central body wall) seems to separate from Spiniferites a group of forms that have a range mainly within the later Cretaceous and earlier Palaeogene: it is this group that we assign to Hafniasphaera. Quattrocchio & Sarjeant's (2003) proposal to consider Hafniasphaera a subgenus of Spiniferites may have some theoretical merit, but is pragmatically awkward and tends to mask the usefulness of this taxon. Hence we prefer to maintain Hafniasphaera as a separate genus.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hafniasphaera Hansen, 1977, is a Spiniferites with a vesicular or vacuolate wall. It has gonal and sutural processes and a P(3") archeopyle. This particular vacuolate wall appears to have a restricted stratigraphic occurrence primarily in the Paleocene, but also in the Eocene.