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Achomosphaera microtriaina
From Fensome et al., 2019:
Achomosphaera microtriaina, (Klumpp, 1953, p.390, pl.17, figs.6–7) Sarjeant, 1981, p.110–112.
Emendation: Sarjeant, 1981, p.110–112, as Achomosphaera microtriaina.
Holotype: Klumpp, 1953, pl.17, figs.6–7; Sarjeant, 1981, pl.2, figs.1–2; text-fig.2.
NOW Operculodinium.
Originally Hystrichosphaeridium, subsequently Cordosphaeridium, thirdly Cordosphaeridium?, fourthly Polysphaeridium, fifthly Achomosphaera, sixthly (and now) Operculodinium.
Age: Late Eocene.
Paratypes: Klumpp, 1953
Locus typicus; Woehrden, Holstein, Germany
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Original description as Hystrichosphaeridium microtriaina: [Klumpp, 1953, p. 390] (Translation: Sarjeant, 1981, p. 111):
Description:
A species of the genus Hystrichosphaeridium, with the following distinguishing characteristics: the membrane of the shell is two-layered. The numerous processes are formed from the outer layer and end in three small hooks.
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Emended description:
Sarjeant, 1981, p. 111-112:
Diagnosis:
Cyst spheroidal to very broadly ovoidal, two-layered. Some 40-50 processes arise from the periphragm; they are gonal and intergonal in situation, slender and tapering slightly from base to tip, hollow but closed distally and proximally. The tips of the processes are capitate to very briefly bifid or trifid, with branchlets of equal or somewhat unequal length; the length of the processes themselves is around one-half of the longest cyst diameter.
Archaeopyle single-plate precingular (type P), of moderate size.
Description:
Proximally, the processes may exhibit very short, root-like extensions: but these are not always conspicuous and may be confined to the gonal processes; certainly they are less conspicuous in, or lacking from, the intergonals. Distally, the capitate to bifid condition appears more common than the trifid. The surface of the phragma is shagreenate to punctate in the specimens examined; not all of the paratypes were seen.
Dimensions:
Holotype length of cyst 48 µm, breadth 50 µm, length of processes 24-26 µm.
Ranges: Length of cyst 44-100 µm, length of processes 12-36 µm.
Achomosphaera microtriaina, (Klumpp, 1953, p.390, pl.17, figs.6–7) Sarjeant, 1981, p.110–112.
Emendation: Sarjeant, 1981, p.110–112, as Achomosphaera microtriaina.
Holotype: Klumpp, 1953, pl.17, figs.6–7; Sarjeant, 1981, pl.2, figs.1–2; text-fig.2.
NOW Operculodinium.
Originally Hystrichosphaeridium, subsequently Cordosphaeridium, thirdly Cordosphaeridium?, fourthly Polysphaeridium, fifthly Achomosphaera, sixthly (and now) Operculodinium.
Age: Late Eocene.
Paratypes: Klumpp, 1953
Locus typicus; Woehrden, Holstein, Germany
---------------------------------------------------------------------------------------------------
Original description as Hystrichosphaeridium microtriaina: [Klumpp, 1953, p. 390] (Translation: Sarjeant, 1981, p. 111):
Description:
A species of the genus Hystrichosphaeridium, with the following distinguishing characteristics: the membrane of the shell is two-layered. The numerous processes are formed from the outer layer and end in three small hooks.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Sarjeant, 1981, p. 111-112:
Diagnosis:
Cyst spheroidal to very broadly ovoidal, two-layered. Some 40-50 processes arise from the periphragm; they are gonal and intergonal in situation, slender and tapering slightly from base to tip, hollow but closed distally and proximally. The tips of the processes are capitate to very briefly bifid or trifid, with branchlets of equal or somewhat unequal length; the length of the processes themselves is around one-half of the longest cyst diameter.
Archaeopyle single-plate precingular (type P), of moderate size.
Description:
Proximally, the processes may exhibit very short, root-like extensions: but these are not always conspicuous and may be confined to the gonal processes; certainly they are less conspicuous in, or lacking from, the intergonals. Distally, the capitate to bifid condition appears more common than the trifid. The surface of the phragma is shagreenate to punctate in the specimens examined; not all of the paratypes were seen.
Dimensions:
Holotype length of cyst 48 µm, breadth 50 µm, length of processes 24-26 µm.
Ranges: Length of cyst 44-100 µm, length of processes 12-36 µm.