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Bohaidina
From Williams et al., 2017:
[Bohaidina, Jiabo, 1978, p. 37; Emendations: Xu Jinli and Mao Shaozhi, 1989, p. 215-216; Sun Xuekun, 1994, p. 70-71.
Type species: Bohaidina laevigata, Jiabo, 1978 (pl.13, fig.1)]
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Original description: [Jiabo, 1978]: (Translation Jiabo, 1978: Chen Yow-yuh, 1988, p. 11):
Description:
Cysts proximate without an endocyst, rhomboidal, ovoidal or roundly quadrangular in outline. Apical, antapical and lateral horns are not evident and indications of a paracingulum and parasulcus are generally absent. However, one or two, possibly secondarily-developed folds occur in the equatorial area. A prominence is present at both ends of the folds on the ventral side. Ornamentation is variable, of low relief, and processes are not present. Archeopyle type uncertain.
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Modified description:
Chen et al., 1988, p. 8-9;
Synopsis:
Cysts proximate, outline in dorsal-ventral view rhombic to roundly quadrangular; a ventral boss-like feature is present near both equatorial-lateral margins; autophragm with features of low relief; no indications of paraplates; archeopyle type uncertain.
Description:
Shape: Rhomboidal to roundly quadrangular in outline.
Wall relationships: Autophragm only.
Wall features: Surface variously ornamented with features of low relief; one or two conspicuous, generally equatorial folds may be present and two boss-like features occur near both equatorial lateral margins.
Archeopyle: Type uncertain, apparently variable; see comment below.
Paratabulation: None indicated.
Paracingulum: Generally not indicated.
Parasulcus: Not indicated.
Size: Intermediate, about 50 µm to 80 µm in length.
Remarks:
Sung Zhi-chen et al., 1978, (al. Jiabo, 1978) stated in their discussion that the archeopyle type is uncertain because among their specimens some archeopyles appear to be apical, some combined apical and intercalary, some precingular, and still other openings are evidently only tears. They further remarked that because the archeopyle type is a significant character in classifying fossil dinoflagellates, it is entirely possible that the group could subsequently be subdivided after a careful study of its archeopyle types. For the present, Bohaidina includes species with different types of archeopyles.
To Sung Zhi-chen et al., 1978, the dorsal-ventrally compressed body (ventrally convex, dorsally concave) suggested that Bohaidina probably is related to the Dinophyceae. The genus has many characteristics of fossil Dinophyceae such as apical pores, apical protrusions, archeopyles and paracingula: some specimens have a paracingular zone (delineated by folds), two ventral prominences, and a depressed transverse area indicating a paracingulum. Thus, Bohaidina is considered to belongs to the Dinophyceae rather than the Acritarcha.
According to Mao Shaozhi, 1986, and based on information supplied to her by Xu Jinli, the archeopyle in Bohaidina is Aa + 3I. Evidence for the combination apical and intercalary archeopyle is presented by Figure 1 of Mao Shaozhi, 1986, a representation of which is our Figure 3B. The opening could be an archeopyle, but it could just as easily be a simple rupture positioned so that it simulates an archeopyle in this one example. One of us (R.Harland) examined specimens of Bohaidina (and of Parabohaidina) from the Bohai Gulf and was unable to identify an archeopyle.
Affinities:
Sung Zhi-chen et al. (1978) indicated that Bohaidina differs from Parabohaidina Sung Zhi-chen et al. 1978 in having prominences in the equatorial ventral area; Parabohaidina lacks such prominences. Among the genera of fossil dinoflagellates whose shapes are similar to those of Bohaidina, some are cavate and each has only one type of archeopyle. Such genera include Komewuia, Cookson and Eisenack 1960, emended Chen 1982 and Rhombodinium Gocht 1955 emended Bujak 1979.
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Emended descriptions:
Xu Jin-li and Mao Shao-zhi, 1989: (Translation Xu Jin-li and Mao Shao-zhi: Fensome et al., 1991, p. 91):
Diagnosis:
Cysts proximate, polyhedral, rhombic to ovoidal in outline. Both apex and antapex extended to form rounded protrusions, the antapical one sometimes slightly more acute than the apical one. Epitract equal to, or slightly larger and wider than, the hypotract, with 2-4 girdle projections along the equator, 2 ventrally and 0-2 dorsally. One or two girdle folds occur, one ventrally and one dorsally when two are present. Wall consists of an autophragm, its surface smooth, granulate, reticulate or spinate. There are no indications of cingulum, sulcus or endoblast. Where discernible the archeopyle involves a combination from the apical and intercalary series ([Xu Jin-li and Mao Shao-zhi, 1989] Fig.1), type (tA)a+3Ia, operculum compound, formed by an apical piece attached ventrally to the cyst and three anterior intercalary plates, each of the latter being separated by accessory archeopyle sutures anteriorly from the apical piece and laterally from each other. The posterior margins of the three intercalary plates are often attached to the precingular series, though sometimes warped or wrenched to some degree or even torn off the cyst. The apical piece is usually attached ventrally to the cyst and is sometimes displaced towards the ventral side. The epitractal tabulation indicated by the archeopyle may be 4`, 3a, 7" with the second intercalary plate (2a) of linteloid type. Cyst of small to medium size.
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GSC: (Provisional translation GSC: courtesy R. Fensome): From Xu Jinli and Mao Shaozhi, 1989:
Remarks/Discussion:
The archeopyle of Bohaidina was thought to be of 3I type like that of Trithyrodinium because one of the authors in the beginning saw a number of specimens which showed either distinct suture separated the apical and intercalary series and sutures separated each of the 3I laterally while their posterior margin attached to the postcingular series, or the 3I free from the cyst completely. Later, however, observations on a large number of specimens (about 200) revealed that most of the specimens showed the three intercalary plates were warped or fallen down inwards or torn away from the cyst, and the apical piece was attached ventrally to the cyst by sulcal tongue or displaced towards the ventral side. The laterally view of specimens show the above character more distinct; when the archeopyle opens first on the dorsal side around the intercalary series, and then ventrally to include the apical series. Once the accessary archeopyle suture separated the apical and intercalary series became ruptured the apical piece (a cap-like) fell down towards the ventral side. This is particular evident under SEM. These facts leave no doubt that the archeopyle of Bohaidina is in fact tAa+3I. The combination archeopyle of such type is easily confused with the A type (when the 3I remain attached) or the 3I type (when the 3I opercula free from the cyst). The peridinoid tabulation and the linteloid 2a suggest that Bohaidina is very similar to the Type B Cyst from the Quaternary post-glacial deposits of Lake Glatsch, Minnesota USA. The latter, however, is a cavate cyst with both apical and antapical horns developed well, but without girdle projections. The rest cyst of Peridinium wisconsinensis Eddy has a biconical shape and apical archeopyle claimed by Wall and Dale, its three intercalary plates separated from apical series by a suture (probably accessary archeopyle), however, suggest its archeopyle type probably like that of Bohaidina, the cavate cyst with both apical and antapical horns of former species can differ from Bohaidina. With the combination archeopyle of tAa+3I and acavate cyst, Bohaidina can easily differ from Ascodinium, Ovoidinium, Diconodinium and Hedbergella.
[Bohaidina, Jiabo, 1978, p. 37; Emendations: Xu Jinli and Mao Shaozhi, 1989, p. 215-216; Sun Xuekun, 1994, p. 70-71.
Type species: Bohaidina laevigata, Jiabo, 1978 (pl.13, fig.1)]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Jiabo, 1978]: (Translation Jiabo, 1978: Chen Yow-yuh, 1988, p. 11):
Description:
Cysts proximate without an endocyst, rhomboidal, ovoidal or roundly quadrangular in outline. Apical, antapical and lateral horns are not evident and indications of a paracingulum and parasulcus are generally absent. However, one or two, possibly secondarily-developed folds occur in the equatorial area. A prominence is present at both ends of the folds on the ventral side. Ornamentation is variable, of low relief, and processes are not present. Archeopyle type uncertain.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Chen et al., 1988, p. 8-9;
Synopsis:
Cysts proximate, outline in dorsal-ventral view rhombic to roundly quadrangular; a ventral boss-like feature is present near both equatorial-lateral margins; autophragm with features of low relief; no indications of paraplates; archeopyle type uncertain.
Description:
Shape: Rhomboidal to roundly quadrangular in outline.
Wall relationships: Autophragm only.
Wall features: Surface variously ornamented with features of low relief; one or two conspicuous, generally equatorial folds may be present and two boss-like features occur near both equatorial lateral margins.
Archeopyle: Type uncertain, apparently variable; see comment below.
Paratabulation: None indicated.
Paracingulum: Generally not indicated.
Parasulcus: Not indicated.
Size: Intermediate, about 50 µm to 80 µm in length.
Remarks:
Sung Zhi-chen et al., 1978, (al. Jiabo, 1978) stated in their discussion that the archeopyle type is uncertain because among their specimens some archeopyles appear to be apical, some combined apical and intercalary, some precingular, and still other openings are evidently only tears. They further remarked that because the archeopyle type is a significant character in classifying fossil dinoflagellates, it is entirely possible that the group could subsequently be subdivided after a careful study of its archeopyle types. For the present, Bohaidina includes species with different types of archeopyles.
To Sung Zhi-chen et al., 1978, the dorsal-ventrally compressed body (ventrally convex, dorsally concave) suggested that Bohaidina probably is related to the Dinophyceae. The genus has many characteristics of fossil Dinophyceae such as apical pores, apical protrusions, archeopyles and paracingula: some specimens have a paracingular zone (delineated by folds), two ventral prominences, and a depressed transverse area indicating a paracingulum. Thus, Bohaidina is considered to belongs to the Dinophyceae rather than the Acritarcha.
According to Mao Shaozhi, 1986, and based on information supplied to her by Xu Jinli, the archeopyle in Bohaidina is Aa + 3I. Evidence for the combination apical and intercalary archeopyle is presented by Figure 1 of Mao Shaozhi, 1986, a representation of which is our Figure 3B. The opening could be an archeopyle, but it could just as easily be a simple rupture positioned so that it simulates an archeopyle in this one example. One of us (R.Harland) examined specimens of Bohaidina (and of Parabohaidina) from the Bohai Gulf and was unable to identify an archeopyle.
Affinities:
Sung Zhi-chen et al. (1978) indicated that Bohaidina differs from Parabohaidina Sung Zhi-chen et al. 1978 in having prominences in the equatorial ventral area; Parabohaidina lacks such prominences. Among the genera of fossil dinoflagellates whose shapes are similar to those of Bohaidina, some are cavate and each has only one type of archeopyle. Such genera include Komewuia, Cookson and Eisenack 1960, emended Chen 1982 and Rhombodinium Gocht 1955 emended Bujak 1979.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended descriptions:
Xu Jin-li and Mao Shao-zhi, 1989: (Translation Xu Jin-li and Mao Shao-zhi: Fensome et al., 1991, p. 91):
Diagnosis:
Cysts proximate, polyhedral, rhombic to ovoidal in outline. Both apex and antapex extended to form rounded protrusions, the antapical one sometimes slightly more acute than the apical one. Epitract equal to, or slightly larger and wider than, the hypotract, with 2-4 girdle projections along the equator, 2 ventrally and 0-2 dorsally. One or two girdle folds occur, one ventrally and one dorsally when two are present. Wall consists of an autophragm, its surface smooth, granulate, reticulate or spinate. There are no indications of cingulum, sulcus or endoblast. Where discernible the archeopyle involves a combination from the apical and intercalary series ([Xu Jin-li and Mao Shao-zhi, 1989] Fig.1), type (tA)a+3Ia, operculum compound, formed by an apical piece attached ventrally to the cyst and three anterior intercalary plates, each of the latter being separated by accessory archeopyle sutures anteriorly from the apical piece and laterally from each other. The posterior margins of the three intercalary plates are often attached to the precingular series, though sometimes warped or wrenched to some degree or even torn off the cyst. The apical piece is usually attached ventrally to the cyst and is sometimes displaced towards the ventral side. The epitractal tabulation indicated by the archeopyle may be 4`, 3a, 7" with the second intercalary plate (2a) of linteloid type. Cyst of small to medium size.
-----------------------------------------------
GSC: (Provisional translation GSC: courtesy R. Fensome): From Xu Jinli and Mao Shaozhi, 1989:
Remarks/Discussion:
The archeopyle of Bohaidina was thought to be of 3I type like that of Trithyrodinium because one of the authors in the beginning saw a number of specimens which showed either distinct suture separated the apical and intercalary series and sutures separated each of the 3I laterally while their posterior margin attached to the postcingular series, or the 3I free from the cyst completely. Later, however, observations on a large number of specimens (about 200) revealed that most of the specimens showed the three intercalary plates were warped or fallen down inwards or torn away from the cyst, and the apical piece was attached ventrally to the cyst by sulcal tongue or displaced towards the ventral side. The laterally view of specimens show the above character more distinct; when the archeopyle opens first on the dorsal side around the intercalary series, and then ventrally to include the apical series. Once the accessary archeopyle suture separated the apical and intercalary series became ruptured the apical piece (a cap-like) fell down towards the ventral side. This is particular evident under SEM. These facts leave no doubt that the archeopyle of Bohaidina is in fact tAa+3I. The combination archeopyle of such type is easily confused with the A type (when the 3I remain attached) or the 3I type (when the 3I opercula free from the cyst). The peridinoid tabulation and the linteloid 2a suggest that Bohaidina is very similar to the Type B Cyst from the Quaternary post-glacial deposits of Lake Glatsch, Minnesota USA. The latter, however, is a cavate cyst with both apical and antapical horns developed well, but without girdle projections. The rest cyst of Peridinium wisconsinensis Eddy has a biconical shape and apical archeopyle claimed by Wall and Dale, its three intercalary plates separated from apical series by a suture (probably accessary archeopyle), however, suggest its archeopyle type probably like that of Bohaidina, the cavate cyst with both apical and antapical horns of former species can differ from Bohaidina. With the combination archeopyle of tAa+3I and acavate cyst, Bohaidina can easily differ from Ascodinium, Ovoidinium, Diconodinium and Hedbergella.