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Areosphaeridium calicigerum
From Fensome et al., 2019:
Areosphaeridium? calcigerum de Coninck, 1986b, p.10, pl.1, figs.8–13. Emendation: Michoux and Masure in Fauconnier and Masure, 2004, p.63. Holotype: de Coninck, 1986b, pl.1, figs.11–13; Fauconnier and Masure, 2004, pl.7, figs.1–3.
Originally Areosphaeridium?, subsequently Surculosphaeridium?, thirdly (and now) Areosphaeridium.
Questionable assignment: de Coninck (1986b, p.10) — however, Michoux and Masure in Fauconnier and Masure
(2004, p.63) retained this species in Areosphaeridium without question (but did not acknowledge the earlier transfer
to Surculosphaeridium). Age: Late Eocene (Tongrian).
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Original description: [De Coninck, 1986, p. 10]:
Diagnosis:
The body is spherical to ovoidal. Its wall is relatively thin, probably an autophragm. The processes are infundibular to buccinate and have a thin to relatively thick and solid stem of variable length. Above their stem the processes widen to form a kind of chalice (latin: calix - icis), which is distally expanded and often recurved. The wall of the proximal part of the chalice is of variable thickness, while the distal part has a very thin wall and a more or less irregular rim.
Around 22 processes can be counted; their distribution is intratabular, one per plate.
The archeopyle is apical with a zig-zag margin.
Dimensions:
of the central body: Holotype: 32 µm long, 29 µm wide. Two other specimens: about 24 µm and 26 µm
Length of the processes: Holotype: from 8 to 13 µm. Two other specimens: from 7 to 13 µm.
Width of the stem of the processes: Holotype: from 1 to 2.5 µm. Two other specimens: from 1 to 2 µm.
Width of the processes distally: Holotype: 9 to 20 µm. Two other specimens: 8 to 15 µm.
Overall dimensions: Holotype: 53 µm long, 47 µm wide. Two other specimens: about 45 µm and 50 µm.
Affinities:
The attribution of the new species to the genus Areosphaeridium Eaton 1971 is provisional. The globular to ovoidal form of the central body with its apical archeopyle and the distribution of the processes remind us of Hystrichosphaerldium; the processes are, however, solid instead of tubular. In Areosphaeridium the processes are solid too but rather fibrous, with a relatively long stem, with distally arcuate and denticulate terminations or a platform-like and fenestrate expanded portion . The processes in A. ? calicigerum with their characteristic chalice-like upper part are not fibrous and very different from those observed in Areosphaeridium. The apical archeopyle was seen in the holotype only. Its zig-zag margin is difficult to observe but indicates the presence of probably six precingular plates, each with one process. Among the other processes the cingular and ventral ones are relatively long and narrow.
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Emendation (Fauconnier and Masure, p. 63) (translated from French):
Emended diagnosis:
Chorate dinoflagellate cyst with a subspherical to ellipsoid central body, subcircular to oval in ambitus. The wall, formed of a thin, smooth-surfaced autophragm, develops 22 to 23 intratabular processes (one per paraplate), vasiform, infundibuliform, solid, non-fibrous. The shaft of the processes branches distally from the same level into two or four branches. The branches are united by a thin, solid, calyx-shaped membrane with wide, flat margins, simulating the corresponding plate (clypeate process). The distribution of the processes reflects a gonyaulacoid paratabulation (4', 6", 6c, 6'", 1p, 1"", 1as, 1ps) of the sexiform type on the hypocyst; the antapical process has a central position. The paracingulum is indicated by 6 fine processes. The parasulcus is underlined by the anterior (as) and posterior (ps) sulcal processes. The archaeopyle is apical, of type (tA). The simple, tetratabular operculum is free.
Areosphaeridium? calcigerum de Coninck, 1986b, p.10, pl.1, figs.8–13. Emendation: Michoux and Masure in Fauconnier and Masure, 2004, p.63. Holotype: de Coninck, 1986b, pl.1, figs.11–13; Fauconnier and Masure, 2004, pl.7, figs.1–3.
Originally Areosphaeridium?, subsequently Surculosphaeridium?, thirdly (and now) Areosphaeridium.
Questionable assignment: de Coninck (1986b, p.10) — however, Michoux and Masure in Fauconnier and Masure
(2004, p.63) retained this species in Areosphaeridium without question (but did not acknowledge the earlier transfer
to Surculosphaeridium). Age: Late Eocene (Tongrian).
---------------------------------------------------------------------------------------------------
Original description: [De Coninck, 1986, p. 10]:
Diagnosis:
The body is spherical to ovoidal. Its wall is relatively thin, probably an autophragm. The processes are infundibular to buccinate and have a thin to relatively thick and solid stem of variable length. Above their stem the processes widen to form a kind of chalice (latin: calix - icis), which is distally expanded and often recurved. The wall of the proximal part of the chalice is of variable thickness, while the distal part has a very thin wall and a more or less irregular rim.
Around 22 processes can be counted; their distribution is intratabular, one per plate.
The archeopyle is apical with a zig-zag margin.
Dimensions:
of the central body: Holotype: 32 µm long, 29 µm wide. Two other specimens: about 24 µm and 26 µm
Length of the processes: Holotype: from 8 to 13 µm. Two other specimens: from 7 to 13 µm.
Width of the stem of the processes: Holotype: from 1 to 2.5 µm. Two other specimens: from 1 to 2 µm.
Width of the processes distally: Holotype: 9 to 20 µm. Two other specimens: 8 to 15 µm.
Overall dimensions: Holotype: 53 µm long, 47 µm wide. Two other specimens: about 45 µm and 50 µm.
Affinities:
The attribution of the new species to the genus Areosphaeridium Eaton 1971 is provisional. The globular to ovoidal form of the central body with its apical archeopyle and the distribution of the processes remind us of Hystrichosphaerldium; the processes are, however, solid instead of tubular. In Areosphaeridium the processes are solid too but rather fibrous, with a relatively long stem, with distally arcuate and denticulate terminations or a platform-like and fenestrate expanded portion . The processes in A. ? calicigerum with their characteristic chalice-like upper part are not fibrous and very different from those observed in Areosphaeridium. The apical archeopyle was seen in the holotype only. Its zig-zag margin is difficult to observe but indicates the presence of probably six precingular plates, each with one process. Among the other processes the cingular and ventral ones are relatively long and narrow.
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Emendation (Fauconnier and Masure, p. 63) (translated from French):
Emended diagnosis:
Chorate dinoflagellate cyst with a subspherical to ellipsoid central body, subcircular to oval in ambitus. The wall, formed of a thin, smooth-surfaced autophragm, develops 22 to 23 intratabular processes (one per paraplate), vasiform, infundibuliform, solid, non-fibrous. The shaft of the processes branches distally from the same level into two or four branches. The branches are united by a thin, solid, calyx-shaped membrane with wide, flat margins, simulating the corresponding plate (clypeate process). The distribution of the processes reflects a gonyaulacoid paratabulation (4', 6", 6c, 6'", 1p, 1"", 1as, 1ps) of the sexiform type on the hypocyst; the antapical process has a central position. The paracingulum is indicated by 6 fine processes. The parasulcus is underlined by the anterior (as) and posterior (ps) sulcal processes. The archaeopyle is apical, of type (tA). The simple, tetratabular operculum is free.