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Bosedinia
From Fensome et al., 2019:
Bosedinia, He Chengquan, 1984b, p.172–173.
Emendations: Chen et al., 1988, p.12–13; Prauss, 2012, p.286,289.
Substitute name for Bosea He Chengquan and Qian Zeshu, 1979, p.177–178 (an illegitimate name).
Type: He Chengquan and Qian Zeshu, 1979, pl.1, fig.2, as Bosea granulata.
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Original description Bosea: He Chen-quan and Qian Ze-shu, 1979: (Translation: Chen et al., 1988, p. 14-15):
Description:
Cysts proximate, spherical to subovoidal. Apical and antapical horns absent. Paracingulum, parasulcus and paratabulation not shown. Archeopyle indicated by a `circular opening`, perhaps of the epicystal type, generally located at the widest part of the body. Operculum adnate or free. Hypocyst larger than epicyst. Surface smooth, scabrate, or rugulate; no spine-like processes.
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Emended description Bosedinia:
Chen et al., 1988:
Synopsis: Cysts proximate, subspherical, autophragm smooth or ornamented with features of low relief; indications of paratabulation absent except for archeopyle sutures which follow the adcingular margins of paraplates 2`, la-3a and 4`; opercular flap evidently composed of paraplates 1`-4` and la-3a, wide area of attachment.
Description:
Shape: Subspherical, but may be modified by folding.
Wall relationships: Autophragm only.
Wall features: Structures expressive of paratabulation absent; wall smooth or uniformly ornamented with features of low relief.
Archeopyle: Combined apical and intercalary, type (tAtI)a, archeopyle suture, which fails to close upon itself, follows the posterior margins of paraplates 2`, la-3a, and 4`; operculum composed of four apical and three intercalary paraplates; operculum normally adnate with a wide area of attachment.
Paratabulation: Expressed by archeopyle or opercular margin on epicyst only; formulae probably peridiniacean: 4`, 3a, 7".
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, about 35 µm to 60 µm in diameter.
Remarks:
In the original description (as Bosea), He Cheng-quan and Qian Ze-shu (1979) were uncertain about the archeopyle and stated that it was indicated by a circular opening and was perhaps of the epicystal type. Later, He Cheng-quan (1984, p. 172-173) reasoned that the archeopyle on Bosedinia was not apical because it lacked the characteristic zigzag margin and accessory sutures and the opening was also too large. On the other hand, He Cheng-quan believed that it was too small to be epicystal and, therefore, the opening represented a transitional archeopyle type which was termed "subepicystal."
Our observations support those of He Cheng-quan (1984). Furthermore, a detailed examination of more than 50 specimens by one of the authors (YYC) demonstrated that the archeopyle margin is as shown in Figure 4B. The adnate operculum is composed of paraplates 1`-4` and 1a-3a (see Figure 4C). This interpretation is based entirely on the archeopyle and opercular outlines since individual paraplates are not delineated on the operculum or elsewhere on the cysts.
Affinities:
Thus, the operculum on Bosedinia is similar to that of Ascodinium Cookson and Eisenack 1960 emended Helenes 1983. However, the operculum on Bosedinia has an exceptionally wide zone of attachment, whereas on Ascodinium the attachment area is narrow. Moreover, the operculum is free on the majority of cavate Ascodinium specimens. The wide attachment zone on Bosedinia results because the sutures between 1" and 1` + 2` and between 7" and 1` + 4` (present in Ascodinium) fail to develop. Other features which serve to distinguish the two genera include the more or less varied shapes of Ascodinium and its more complex wall relationships and layering.
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Prauss, 2012:
Diagnosis: The diagnosis is emended here to include cysts with wall alveolation and/or fine, hair-like processes evenly distributed on the surface of the cyst.
Bosedinia, He Chengquan, 1984b, p.172–173.
Emendations: Chen et al., 1988, p.12–13; Prauss, 2012, p.286,289.
Substitute name for Bosea He Chengquan and Qian Zeshu, 1979, p.177–178 (an illegitimate name).
Type: He Chengquan and Qian Zeshu, 1979, pl.1, fig.2, as Bosea granulata.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description Bosea: He Chen-quan and Qian Ze-shu, 1979: (Translation: Chen et al., 1988, p. 14-15):
Description:
Cysts proximate, spherical to subovoidal. Apical and antapical horns absent. Paracingulum, parasulcus and paratabulation not shown. Archeopyle indicated by a `circular opening`, perhaps of the epicystal type, generally located at the widest part of the body. Operculum adnate or free. Hypocyst larger than epicyst. Surface smooth, scabrate, or rugulate; no spine-like processes.
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-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description Bosedinia:
Chen et al., 1988:
Synopsis: Cysts proximate, subspherical, autophragm smooth or ornamented with features of low relief; indications of paratabulation absent except for archeopyle sutures which follow the adcingular margins of paraplates 2`, la-3a and 4`; opercular flap evidently composed of paraplates 1`-4` and la-3a, wide area of attachment.
Description:
Shape: Subspherical, but may be modified by folding.
Wall relationships: Autophragm only.
Wall features: Structures expressive of paratabulation absent; wall smooth or uniformly ornamented with features of low relief.
Archeopyle: Combined apical and intercalary, type (tAtI)a, archeopyle suture, which fails to close upon itself, follows the posterior margins of paraplates 2`, la-3a, and 4`; operculum composed of four apical and three intercalary paraplates; operculum normally adnate with a wide area of attachment.
Paratabulation: Expressed by archeopyle or opercular margin on epicyst only; formulae probably peridiniacean: 4`, 3a, 7".
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small to intermediate, about 35 µm to 60 µm in diameter.
Remarks:
In the original description (as Bosea), He Cheng-quan and Qian Ze-shu (1979) were uncertain about the archeopyle and stated that it was indicated by a circular opening and was perhaps of the epicystal type. Later, He Cheng-quan (1984, p. 172-173) reasoned that the archeopyle on Bosedinia was not apical because it lacked the characteristic zigzag margin and accessory sutures and the opening was also too large. On the other hand, He Cheng-quan believed that it was too small to be epicystal and, therefore, the opening represented a transitional archeopyle type which was termed "subepicystal."
Our observations support those of He Cheng-quan (1984). Furthermore, a detailed examination of more than 50 specimens by one of the authors (YYC) demonstrated that the archeopyle margin is as shown in Figure 4B. The adnate operculum is composed of paraplates 1`-4` and 1a-3a (see Figure 4C). This interpretation is based entirely on the archeopyle and opercular outlines since individual paraplates are not delineated on the operculum or elsewhere on the cysts.
Affinities:
Thus, the operculum on Bosedinia is similar to that of Ascodinium Cookson and Eisenack 1960 emended Helenes 1983. However, the operculum on Bosedinia has an exceptionally wide zone of attachment, whereas on Ascodinium the attachment area is narrow. Moreover, the operculum is free on the majority of cavate Ascodinium specimens. The wide attachment zone on Bosedinia results because the sutures between 1" and 1` + 2` and between 7" and 1` + 4` (present in Ascodinium) fail to develop. Other features which serve to distinguish the two genera include the more or less varied shapes of Ascodinium and its more complex wall relationships and layering.
--------------------------
Prauss, 2012:
Diagnosis: The diagnosis is emended here to include cysts with wall alveolation and/or fine, hair-like processes evenly distributed on the surface of the cyst.