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Hapsocysta
From Williams et al., 2017:
[Hapsocysta, Davey, 1979b, p. 556. Emendation: Heilmann-Clausen and Van Simaeys, 2005, p. 166.
Type species: originally as Cannosphaeropsis peridictya, Eisenack and Cookson, 1960 (pl.3, fig.6)] ; Hapsocysta peridictya, emend. Davey, 1979
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Original description: [Davey, 1979b]:
Description:
The cyst consists of a subspherical endocyst which almost completely enveloped by a net-like periphragm structure; the areas between the strands may be filled by a subsidiary network. The net is joined to the endocyst only around the circumference of the archeopyle which is dorsal precingular (3``) and this is the only part of the cyst not enclosed by the net. The mesh of the net is composed of a single strand or two closely adhering strands which are parasutural in position and define a tabulation. This consists of large, basically pentagonal, pre-, postcingular, and antapical areas, elongate paracingular areas and small, subcircular parasulcal areas; apical areas do not appear to be defined.
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Modified description:
Stover and Williams 1987, p. 119-120:
Synopsis:
Pericyst subspherical(?); endocyst surrounded by net-like trabecular periphragm; spaces between trabeculae open or partly filled by perforate membranes; trabeculae parasutural, paratabulation formula unknown; archeopyle precingular, Type P, (3``), operculum evidently free. Modified description:
Shape: Endocyst and pericyst probably subspherical, but shape usually distorted because of folding and collapsing.
Wall relationships: Periphragm connected to endophragm only around the margin of the archeopyle.
Wall features: Periphragm consists of trabecular net-like body, the pericyst, with the spaces between the trabeculae open or partly filled by perforate membranes; endophragm apparently smooth or faintly ornamented.
Archeopyle: Precingular, type P, (3`` only); operculum evidently free.
Paratabulation: Supposedly indicated by parasutural trabeculae; formula as well as shapes and relationships not given.
Paracingulum: Paraplates evidently indicated by parasutural trabeculae; details not given.
Parasulcus: As above.
Size: Small to large; diameter from about 45 µm to 110 µm.
Affinities:
Hapsocysta differs from Evittosphaerula Manum 1979 in possessing an endocyst.
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Emended description:
Heilmann-Clausen and Van Simaeys, 2005:
Emendation:
Four apical paraplates are present in this genus (Text-Figure 6). These paraplates are recognized by parasutural strands similar to those present at the parasutures of the other paraplate series. Other features of the genus are as stated in the original diagnosis of Davey (1979).
Remarks:
When Davey (1979) established this genus, he mentioned that the “apical areas do not appear to be defined”. The type species of the genus is Hapsocysta peridictya (Eisenack & Cookson 1960) Davey 1979. In Text-Figure 6, we have reproduced an illustration of the holotype of Hapsocysta peridictya from Eisenack and Cookson (1960). In Text-figure 6 we have also shown our interpretation of the paratabulation. Two possible scenarios are shown; both interpretations clearly show a normal gonyaulacacean apical region with four apical paraplates. The details of these interpretations are explained in the caption of Text-Figure 6. The genus Piccoladinium Versteegh & Zevenboom 1995 is considered to be a junior synonym of Hapsocysta because the generic difference was stated to be the presence of an apical paraplate series in Piccoladinium. The single species of Piccoladinium, Piccoladinium fenestratum Versteegh & Zevenboom 1995, is therefore transferred here to Hapsocysta.
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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.
Hapsocysta Davey, 1979b. Stover and Williams (1987) provided the following synopsis. Pericyst subspherical(?), endocyst surrounded by netlike trabecular periphragm (only joined to the endocyst at the archeopyle margin); spaces between trabeculae open or partly filled by perforate membranes; trabeculae parasutural, paratabulation formula unknown, archeopyle precingular, type P (3"), operculum evidently free.
[Hapsocysta, Davey, 1979b, p. 556. Emendation: Heilmann-Clausen and Van Simaeys, 2005, p. 166.
Type species: originally as Cannosphaeropsis peridictya, Eisenack and Cookson, 1960 (pl.3, fig.6)] ; Hapsocysta peridictya, emend. Davey, 1979
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Original description: [Davey, 1979b]:
Description:
The cyst consists of a subspherical endocyst which almost completely enveloped by a net-like periphragm structure; the areas between the strands may be filled by a subsidiary network. The net is joined to the endocyst only around the circumference of the archeopyle which is dorsal precingular (3``) and this is the only part of the cyst not enclosed by the net. The mesh of the net is composed of a single strand or two closely adhering strands which are parasutural in position and define a tabulation. This consists of large, basically pentagonal, pre-, postcingular, and antapical areas, elongate paracingular areas and small, subcircular parasulcal areas; apical areas do not appear to be defined.
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Modified description:
Stover and Williams 1987, p. 119-120:
Synopsis:
Pericyst subspherical(?); endocyst surrounded by net-like trabecular periphragm; spaces between trabeculae open or partly filled by perforate membranes; trabeculae parasutural, paratabulation formula unknown; archeopyle precingular, Type P, (3``), operculum evidently free. Modified description:
Shape: Endocyst and pericyst probably subspherical, but shape usually distorted because of folding and collapsing.
Wall relationships: Periphragm connected to endophragm only around the margin of the archeopyle.
Wall features: Periphragm consists of trabecular net-like body, the pericyst, with the spaces between the trabeculae open or partly filled by perforate membranes; endophragm apparently smooth or faintly ornamented.
Archeopyle: Precingular, type P, (3`` only); operculum evidently free.
Paratabulation: Supposedly indicated by parasutural trabeculae; formula as well as shapes and relationships not given.
Paracingulum: Paraplates evidently indicated by parasutural trabeculae; details not given.
Parasulcus: As above.
Size: Small to large; diameter from about 45 µm to 110 µm.
Affinities:
Hapsocysta differs from Evittosphaerula Manum 1979 in possessing an endocyst.
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Emended description:
Heilmann-Clausen and Van Simaeys, 2005:
Emendation:
Four apical paraplates are present in this genus (Text-Figure 6). These paraplates are recognized by parasutural strands similar to those present at the parasutures of the other paraplate series. Other features of the genus are as stated in the original diagnosis of Davey (1979).
Remarks:
When Davey (1979) established this genus, he mentioned that the “apical areas do not appear to be defined”. The type species of the genus is Hapsocysta peridictya (Eisenack & Cookson 1960) Davey 1979. In Text-Figure 6, we have reproduced an illustration of the holotype of Hapsocysta peridictya from Eisenack and Cookson (1960). In Text-figure 6 we have also shown our interpretation of the paratabulation. Two possible scenarios are shown; both interpretations clearly show a normal gonyaulacacean apical region with four apical paraplates. The details of these interpretations are explained in the caption of Text-Figure 6. The genus Piccoladinium Versteegh & Zevenboom 1995 is considered to be a junior synonym of Hapsocysta because the generic difference was stated to be the presence of an apical paraplate series in Piccoladinium. The single species of Piccoladinium, Piccoladinium fenestratum Versteegh & Zevenboom 1995, is therefore transferred here to Hapsocysta.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hapsocysta Davey, 1979b. Stover and Williams (1987) provided the following synopsis. Pericyst subspherical(?), endocyst surrounded by netlike trabecular periphragm (only joined to the endocyst at the archeopyle margin); spaces between trabeculae open or partly filled by perforate membranes; trabeculae parasutural, paratabulation formula unknown, archeopyle precingular, type P (3"), operculum evidently free.