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Achomosphaera neptuni
Achomosphaera neptuni, (Eisenack, 1958a, p. 399, pl.26, figs.7–8; text-fig.8), Davey and Williams, 1966a, p. 51-52 (pl.3, fig.7; pl.9, fig.11); Emendations: as Spiniferites neptuni, Duxbury, 1983, p. 55; as Florentinia? neptuni, Sarjeant, 1985a, p.89–90,92
Originally Baltisphaeridium, subsequently (and now) Achomosphaera, thirdly Achomosphaera?, fourthly Spiniferites, fifthly Florentinia?.
Questionable assignment: Stover and Evitt (1978, p.139) - however, J.K. Lister and Batten (1988b, p.31-32) retained it in Achomosphaera without question. Since the epithet is based on a given name, it ends in "i" rather than "ii" (I.C.B.N. Recommendation 60C.2).
Holotype: Eisenack, 1958a, pl.26. fig.7
Age: Early Cretaceous.
Locus typicus: Borehole at Feld Heide, NW Germany
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Original description as Baltisphaeridium neptuni: [Eisenack 1958, p. 399] (Translation: LPP):
Diagnosis:
Shell with thin wall, spherical to oval, covered with few, broadly based, cylindrical to weakly conical appendices; these are thin-walled, hollow and distally usually divided into 3 (more rarely 2 or 4) strongly diverging, mostly widely diverging, pointed processes. The length of the appendices is about half the central body diameter, or slightly shorter.
Dimensions:
12 specimens: shell diameter 40-60 µm, total diameter 75-95 µm;
Holotype 48 µm and 88 µm respectively.
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Description as Achomosphaera neptuni: [Davey and Williams 1966, p. 51]:
Diagnosis:
A. neptuni possesses a central body with a reticulate or sometimes slightly fibrous surface.
The processes are gonal in position, taeniate or taeniate-triangular and may be bifurcate or trifurcate. In the cingular zone the processes are branched. The processes are fibrous, the fibres sometimes radiating from the bases of the processes and these may be slightly thickened along the reflected plate boundaries joining the processes.
A precingular archaeopyle is often present.
Dimensions:
1st specimen diameter of central body 61x66 µm, length of processes up to 28µm.
2nd specimen diameter of central body 47x52 µm, length of processes up to 21 µm.
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Emended description as Florentinia? neptuni:
Sarjeant, 1985a, p.90, 92:
Description:
Proximochorate to chorate cysts, intratabulate, with a spheroidal to broadly ovoidal central body. Processes all closed distally and of three principal types: (a) Large and cylindrical or compressed-cylindrical or saddle-shaped processes, giving rise to 4-6 short, bifurcate or ramifying branches, correspond to the largest paraplates. These processes exhibit, frequently or consistently, perforations of variable size and density; (b) Tubiform to ipniate or slightly tapering processes of smaller dimension, trifurcate or tetrafurcate distally and again often perforate, correspond to the other paraplates of the epitract and hypotract. These vary in size in relation to the paraplate to which they correspond; (c) Unbranched processes, acuminate or tapering, correspond to some, at least, of the small sulcal paraplates. Length of processes around 30% of the central body breadth. Sutures between paraplates not marked.
Paratabulation gonyaulacacean, probably 4', 0a, 6", 6c, 5'?, 6''', 1p, 1''''. Surface of phragma granulate to shagreenate or reticulate.
Archaeopyle probably single-plate precingular (type P), formed by loss of paraplate 3".
Dimensions:
Holotype: overall length 86 µm, overall breadth 88 µm, length of central body 50 µm, breadth 47 µm. Unique (other specimens seen not in
accord with this morphotype).
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Achomosphaera neptuni (Eisenack, 1958a) Davey and Williams, 1966a. According to Duxbury (1983, p.55), has trifurcate gonal and bifurcate parasutural processes, which may be connected by low crests. Rarely the processes have a second bifurcation. The processes appear to be fibrous. The archeopyle is precingular. Central body 40 to 60 µm. Overall 75 to 90 µm
Originally Baltisphaeridium, subsequently (and now) Achomosphaera, thirdly Achomosphaera?, fourthly Spiniferites, fifthly Florentinia?.
Questionable assignment: Stover and Evitt (1978, p.139) - however, J.K. Lister and Batten (1988b, p.31-32) retained it in Achomosphaera without question. Since the epithet is based on a given name, it ends in "i" rather than "ii" (I.C.B.N. Recommendation 60C.2).
Holotype: Eisenack, 1958a, pl.26. fig.7
Age: Early Cretaceous.
Locus typicus: Borehole at Feld Heide, NW Germany
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Baltisphaeridium neptuni: [Eisenack 1958, p. 399] (Translation: LPP):
Diagnosis:
Shell with thin wall, spherical to oval, covered with few, broadly based, cylindrical to weakly conical appendices; these are thin-walled, hollow and distally usually divided into 3 (more rarely 2 or 4) strongly diverging, mostly widely diverging, pointed processes. The length of the appendices is about half the central body diameter, or slightly shorter.
Dimensions:
12 specimens: shell diameter 40-60 µm, total diameter 75-95 µm;
Holotype 48 µm and 88 µm respectively.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Description as Achomosphaera neptuni: [Davey and Williams 1966, p. 51]:
Diagnosis:
A. neptuni possesses a central body with a reticulate or sometimes slightly fibrous surface.
The processes are gonal in position, taeniate or taeniate-triangular and may be bifurcate or trifurcate. In the cingular zone the processes are branched. The processes are fibrous, the fibres sometimes radiating from the bases of the processes and these may be slightly thickened along the reflected plate boundaries joining the processes.
A precingular archaeopyle is often present.
Dimensions:
1st specimen diameter of central body 61x66 µm, length of processes up to 28µm.
2nd specimen diameter of central body 47x52 µm, length of processes up to 21 µm.
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Emended description as Florentinia? neptuni:
Sarjeant, 1985a, p.90, 92:
Description:
Proximochorate to chorate cysts, intratabulate, with a spheroidal to broadly ovoidal central body. Processes all closed distally and of three principal types: (a) Large and cylindrical or compressed-cylindrical or saddle-shaped processes, giving rise to 4-6 short, bifurcate or ramifying branches, correspond to the largest paraplates. These processes exhibit, frequently or consistently, perforations of variable size and density; (b) Tubiform to ipniate or slightly tapering processes of smaller dimension, trifurcate or tetrafurcate distally and again often perforate, correspond to the other paraplates of the epitract and hypotract. These vary in size in relation to the paraplate to which they correspond; (c) Unbranched processes, acuminate or tapering, correspond to some, at least, of the small sulcal paraplates. Length of processes around 30% of the central body breadth. Sutures between paraplates not marked.
Paratabulation gonyaulacacean, probably 4', 0a, 6", 6c, 5'?, 6''', 1p, 1''''. Surface of phragma granulate to shagreenate or reticulate.
Archaeopyle probably single-plate precingular (type P), formed by loss of paraplate 3".
Dimensions:
Holotype: overall length 86 µm, overall breadth 88 µm, length of central body 50 µm, breadth 47 µm. Unique (other specimens seen not in
accord with this morphotype).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Achomosphaera neptuni (Eisenack, 1958a) Davey and Williams, 1966a. According to Duxbury (1983, p.55), has trifurcate gonal and bifurcate parasutural processes, which may be connected by low crests. Rarely the processes have a second bifurcation. The processes appear to be fibrous. The archeopyle is precingular. Central body 40 to 60 µm. Overall 75 to 90 µm