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Bonbonadinium
From Fensome et al., 2019:
Bonbonadinium, Helby and Partridge, 2001, p.221.
Type: Helby and Partridge, 2001, figs.1K–L, as Bonbonadinium granulatum.
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Original description: [Helby and Partridge, 2001]:
Diagnosis:
Small to intermediate in size, elongate ellipsoidal to cylindrical, taking into account apical and antapical coronas. Endophragm and periphragm closely appressed, except at the extremities where the periphragm is extended to form the apical and antapical coronas.
Paratabulation generally expressed by archaeopyle, accessory archaeopyle sutures and the parasulcal notch; rarely by low parasutural ridges close to the polar extremities.
Archaeopyle apical, type tA; operculum free, bearing distinctive corona.
Paracingulum not indicated.
Parasulcus not indicated, apart from parasulcal notch.
Affinities:
Bonbonadinium differs from other dinoflagellate cyst genera in its elongate shape and polar coronas. It resembles the Cenomanian acritarch Bipatellifera Singh 1983 but the latter apparently lacks an archeopyle and has trabeculate polar "dish-like structures". Some dinoflagellate cyst genera bear hypocystal coronas. Stephanelytron Sarjeant emend. Stover, Sarjaent & Drugg, 1977 is subspherical and exhibits numerous short processes. Lagenadinium Piel 1985 is characterised by usually having one hypocystal corona, with rare specimens having two. It also has a spherical to subspherical outline and distinct ectophragm development. Neither of these two genera exhibits an antapical corona. Balcattia Cookson & Eisenack 1974 emend. Riding & Helby (this volume), has similar apical and antapical projections but these consist of distally trabeculate process clusters, rather than simple coronas.
Bonbonadinium, Helby and Partridge, 2001, p.221.
Type: Helby and Partridge, 2001, figs.1K–L, as Bonbonadinium granulatum.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Helby and Partridge, 2001]:
Diagnosis:
Small to intermediate in size, elongate ellipsoidal to cylindrical, taking into account apical and antapical coronas. Endophragm and periphragm closely appressed, except at the extremities where the periphragm is extended to form the apical and antapical coronas.
Paratabulation generally expressed by archaeopyle, accessory archaeopyle sutures and the parasulcal notch; rarely by low parasutural ridges close to the polar extremities.
Archaeopyle apical, type tA; operculum free, bearing distinctive corona.
Paracingulum not indicated.
Parasulcus not indicated, apart from parasulcal notch.
Affinities:
Bonbonadinium differs from other dinoflagellate cyst genera in its elongate shape and polar coronas. It resembles the Cenomanian acritarch Bipatellifera Singh 1983 but the latter apparently lacks an archeopyle and has trabeculate polar "dish-like structures". Some dinoflagellate cyst genera bear hypocystal coronas. Stephanelytron Sarjeant emend. Stover, Sarjaent & Drugg, 1977 is subspherical and exhibits numerous short processes. Lagenadinium Piel 1985 is characterised by usually having one hypocystal corona, with rare specimens having two. It also has a spherical to subspherical outline and distinct ectophragm development. Neither of these two genera exhibits an antapical corona. Balcattia Cookson & Eisenack 1974 emend. Riding & Helby (this volume), has similar apical and antapical projections but these consist of distally trabeculate process clusters, rather than simple coronas.