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Wallodinium
From Fensome et al., 2019:
Wallodinium Loeblich Jr. and Loeblich III, 1968, p.212.
Emendation: Riding, 1994, p.17–18.
Substitute name for Diplotesta Cookson and Eisenack, 1960b, p.256 (an illegitimate name).
Duxbury (1983, p.68) and Fensome et al. (1990, p.535) considered this genus to represent acritarchs; however, Riding (1994, p.17–18) confirmed its dinoflagellate affinity.
Type: Cookson and Eisenack, 1960b, pl.39, fig.4, as Diplotesta glaessneri.
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Original description as Diplotesta: [Cookson and Eisenack 1960, p. 256]:
Diagnosis:
Shell cylindrical or elongate-ellipsoidal, straight or curved, with rounded or bluntly pointed apices and partially filled with an elongate oval capsule. Membrane of shell smooth or finely and longitudinally striate; wall of capsule smooth.
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Modified description Wallodinium:
Stover and Evitt 1978, p. 87:
Synopsis:
Cysts cavate, generally bicavate, rarely circumcavate, elongate ellipsoidal to crescent-shaped; endocyst appreciable shorter than pericyst; archeopyle at anterior apices.
Description:
Shape: Elongate ellipsoidal to crescent-shaped.
Wall Relationships: Cysts generally bicavate, rarely circumcavate; endocyst ellipsoidal, appreciably shorter than pericyst; resulting apical and antapical pericoels commonly prominent.
Wall Features: No parasutural features. Periphragm smooth or longitudinally striate; endophragm smooth or faintly ornamented.
Paratabulation: Essentially not indicated.
Archeopyle: At anterior apices of pericyst and endocyst; suture of periarcheopyle straight to jagged, and of endoarcheopyle, straight. Opercula small, normally attached, and widely separated from each other.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large.
Affinities:
Wallodinium differs from Svalbardella in having an apical rather than an intercalary archeopyle, and in essentially lacking indications of paratabulation. No crescent-shaped forms of Svalbardella are known.
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Emended description Wallodinium:
Riding, 1994:
Diagnosis:
Longitudinally elongate, subcylindrical, proximate, cavate dinoflagellate cysts. Ambitus may be crescent-shaped and has tapering or broadly rounded antapical and antapical apices. Cavation style bicavate, circumcavate or epicavate. Endocyst markedly shorter than pericyst, ellipsoidal to subcylindrical; short apical and antapical horns may be present.
Periphragm generally thinner than endophragm. Both cyst layers smooth or having low-relief ornamentation; periphragm and endophragm may be in loose mutual contact.
Parasutural features generally lacking.
Peri- and endoarcheopyle apical, type tA, peri- and endopercula attached or free. The principal periarcheopyle suture may indicate the presence of four apical paraplates, six precingular paraplates and a single anterior parasulcal paraplate in a gonyaulacacean configuration.
Paracingulum may be indicated by an equatorial constriction and/or vague lineations of ornamentation. Parasulcus may be indicated by a flagellar scar.
Description:
A small to large (of Stover and Evitt,1978) proximate, cavate genus. The ambitus is longitudinally elongate and is straight to crescentic and subcylindrical. The pericyst may have sharply pointed or rounded apices and the endocyst is normally subcylindrical (rarely subspherical) and can have short horns at each extremity. Species are bicavate, circumcavate or epicavate. The epi- and hypopericoels (where the latter are developed) are generally relatively large due to the marked disparity in length of the epi- and pericyst.
Peri- and endophragm smooth to faintly ornamented and may be in loose contact. The peri- and endoarcheopyles are apical (tA); the opercula are adnate ventrally or free. The periarcheopyle suture may denote a partial Kofoidian paratabulation formula of ?pr,4`, 6`, as.
The paracingulum and parasulcus may be indicated by an equatorial concavity (and/or low parasutural relief) and a flagellar scar respectively.
Remarks:
The generic diagnosis of Wallodinium required emendation largely to emphasis the nature of the variation in cavation throughout the genus and to note the existence of apparent gonyaulacacean paratabulation from evidence provided by the principal periarcheopyle suture in W. cylindricum (Habib 1970) Duxbury 1980 emend. nov. The majority of Wallodinium species are circumcavate or bicavate and Wallodinium cylindricum is epicavate. The original diagnosis of Cookson and Eisenack (1960) stated only that the periphragm ("shell") is "partly filled" by the endocyst ("capsule"). Furthermore, no mention of the archeopyle is included in the original diagnosis. Stover & Evitt (1978, p.87), in a `modified description,` noted that the genus has an apical archeopyle with a straight to jagged principal periarcheopyle suture and a straight principal endoarcheopyle suture. The lack of data on the archeopyle style in the original diagnosis is probably the main reason that Duxbury (1980,1983), Yun (1981) and Fensome et al. (1990, 1993) classified Wallodinium as an acritarch.
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Poulsen 1996, p. 89:
Remarks:
Wallodinium is here treated as an acritarch, as it does not convincingly belong to the dinoflagellates.
Wallodinium Loeblich Jr. and Loeblich III, 1968, p.212.
Emendation: Riding, 1994, p.17–18.
Substitute name for Diplotesta Cookson and Eisenack, 1960b, p.256 (an illegitimate name).
Duxbury (1983, p.68) and Fensome et al. (1990, p.535) considered this genus to represent acritarchs; however, Riding (1994, p.17–18) confirmed its dinoflagellate affinity.
Type: Cookson and Eisenack, 1960b, pl.39, fig.4, as Diplotesta glaessneri.
---------------------------------------------------------------------------------------------------
Original description as Diplotesta: [Cookson and Eisenack 1960, p. 256]:
Diagnosis:
Shell cylindrical or elongate-ellipsoidal, straight or curved, with rounded or bluntly pointed apices and partially filled with an elongate oval capsule. Membrane of shell smooth or finely and longitudinally striate; wall of capsule smooth.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description Wallodinium:
Stover and Evitt 1978, p. 87:
Synopsis:
Cysts cavate, generally bicavate, rarely circumcavate, elongate ellipsoidal to crescent-shaped; endocyst appreciable shorter than pericyst; archeopyle at anterior apices.
Description:
Shape: Elongate ellipsoidal to crescent-shaped.
Wall Relationships: Cysts generally bicavate, rarely circumcavate; endocyst ellipsoidal, appreciably shorter than pericyst; resulting apical and antapical pericoels commonly prominent.
Wall Features: No parasutural features. Periphragm smooth or longitudinally striate; endophragm smooth or faintly ornamented.
Paratabulation: Essentially not indicated.
Archeopyle: At anterior apices of pericyst and endocyst; suture of periarcheopyle straight to jagged, and of endoarcheopyle, straight. Opercula small, normally attached, and widely separated from each other.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large.
Affinities:
Wallodinium differs from Svalbardella in having an apical rather than an intercalary archeopyle, and in essentially lacking indications of paratabulation. No crescent-shaped forms of Svalbardella are known.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description Wallodinium:
Riding, 1994:
Diagnosis:
Longitudinally elongate, subcylindrical, proximate, cavate dinoflagellate cysts. Ambitus may be crescent-shaped and has tapering or broadly rounded antapical and antapical apices. Cavation style bicavate, circumcavate or epicavate. Endocyst markedly shorter than pericyst, ellipsoidal to subcylindrical; short apical and antapical horns may be present.
Periphragm generally thinner than endophragm. Both cyst layers smooth or having low-relief ornamentation; periphragm and endophragm may be in loose mutual contact.
Parasutural features generally lacking.
Peri- and endoarcheopyle apical, type tA, peri- and endopercula attached or free. The principal periarcheopyle suture may indicate the presence of four apical paraplates, six precingular paraplates and a single anterior parasulcal paraplate in a gonyaulacacean configuration.
Paracingulum may be indicated by an equatorial constriction and/or vague lineations of ornamentation. Parasulcus may be indicated by a flagellar scar.
Description:
A small to large (of Stover and Evitt,1978) proximate, cavate genus. The ambitus is longitudinally elongate and is straight to crescentic and subcylindrical. The pericyst may have sharply pointed or rounded apices and the endocyst is normally subcylindrical (rarely subspherical) and can have short horns at each extremity. Species are bicavate, circumcavate or epicavate. The epi- and hypopericoels (where the latter are developed) are generally relatively large due to the marked disparity in length of the epi- and pericyst.
Peri- and endophragm smooth to faintly ornamented and may be in loose contact. The peri- and endoarcheopyles are apical (tA); the opercula are adnate ventrally or free. The periarcheopyle suture may denote a partial Kofoidian paratabulation formula of ?pr,4`, 6`, as.
The paracingulum and parasulcus may be indicated by an equatorial concavity (and/or low parasutural relief) and a flagellar scar respectively.
Remarks:
The generic diagnosis of Wallodinium required emendation largely to emphasis the nature of the variation in cavation throughout the genus and to note the existence of apparent gonyaulacacean paratabulation from evidence provided by the principal periarcheopyle suture in W. cylindricum (Habib 1970) Duxbury 1980 emend. nov. The majority of Wallodinium species are circumcavate or bicavate and Wallodinium cylindricum is epicavate. The original diagnosis of Cookson and Eisenack (1960) stated only that the periphragm ("shell") is "partly filled" by the endocyst ("capsule"). Furthermore, no mention of the archeopyle is included in the original diagnosis. Stover & Evitt (1978, p.87), in a `modified description,` noted that the genus has an apical archeopyle with a straight to jagged principal periarcheopyle suture and a straight principal endoarcheopyle suture. The lack of data on the archeopyle style in the original diagnosis is probably the main reason that Duxbury (1980,1983), Yun (1981) and Fensome et al. (1990, 1993) classified Wallodinium as an acritarch.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Poulsen 1996, p. 89:
Remarks:
Wallodinium is here treated as an acritarch, as it does not convincingly belong to the dinoflagellates.