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Florentinia
From Williams et al., 2017:
[Florentinia, Davey and Verdier, 1973, p. 185–186; Emendation: Duxbury, 1980, p. 119-120
Type species: Florentinia laciniata, Davey and Verdier, 1973 (pl.2, figs.1,3)]
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Original description: [Davey and Verdier, 1973]:
Diagnosis:
The cysts are subspherical and bear one intratabular process per reflected plate area. The processes are hollow, apparently open distally and usually slightly fibrous. A distinctively large, tubular antapical process is typically present; it is usually open distally and may rarely give rise to secondary tubules distally. The pre- and postcingular processes are large, relatively wide proximally, and terminate distally with a simple funnel or a number of tubules. The apical processes are similar but generally smaller. The cingular and sulcal processes are finer, open distally and may be deeply furcate.
The reflected tabulation is 3-4`, 6``, 6c, 5```, 1p, 1```` and 2-5s.
The position of the archaeopyle is either precingular (3``), with sometimes an incipient apical-precingular tear, or is formed by the loss of the third precingular plate (3``) and the apical plates.
Affinities:
Florentinia differs from previously described genera by the possession of either a precingular or combination archaeopyle, a distinctive tubular antapical process and regularly arranged processes that are apparently open distally. The only closely related species to be described have been placed in the Tertiary genus Hystrichokolpoma Klumpp 1953; it is, in fact, considered that Florentinia is ancestral to Hystrichokolpoma. The two genera are basically similar, the main difference being that the latter genus possesses only an apical archaeopyle.
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Modified description:
Stover and Evitt 1978, p. 155-156:
Synopsis:
Cysts skolochorate, body subspherical; paratabulation gonyaulacacean, indicated by intratabular processes of two sizes, with the narrower processes in paracingular and parasulcal areas; large distinctive antapical process typically present; archeopyle precingular, type P, or combination, Type tA+P.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. intratabular processes hollow, smooth, or faintly striate, normally open distally; tips truncate or variously subdivided and may be drawn out into short tubules. Periphragm smooth or finely granulate.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, formula: 3-4`, 6``, 6c, 5```, 1p, 1````, 2-5s. Postcingular paraplates interpreted as reflecting plates 2``` to 6```. Antapical process usually distinctly different from the others and may be closed distally.
Archeopyle: Either precingular, Type P (3`` only), with or without an incipient apical-precingular tear, or combination, Type tA+P; operculum free. Paracingulum: Indicated by six equatorial processes with transversely elongate bases and one or more tips.
Parasulcus: Indicated by two to five processes; anterior and posterior parasulcal processes of intermediate size and usually slightly wider than other parasulcal processes.
Size: Intermediate to large.
Affinities:
Florentinia differs from Silicisphaera in having a distinctively large antapical process, which Silicisphaera lacks, and in generally less complex processes in the precingular and postcingular series. Consistent separation of Florentinia and Silicisphaera may be difficult because of intergradational features. Florentinia differs from Hystrichokolpoma in having either a precingular or a combination archeopyle (Type tA+P) rather than an apical archeopyle (Type tA).
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Emended description:
Duxbury, 1980:
Diagnosis:
Spheroidal to ellipsoidal dinoflagellate cysts bearing large epi- and hypocystal processes which reflect a paratabulation of the formula 4`, 6``, 5```, 1````. There are a variable number of paracingular and parasulcal processes. The epi- and hypocystal process form is very variable and ranges from single tubes which are open, partially closed or closed distally to process complexes composed of distally tapering, free-standing spines or tubules which impart a complex appearance to the cyst but which nevertheless represent only a few processes. Some variation in process size is usually apparent with the order of increasing size being paracingular and parasulcal, apical, precingular and postcingular. The antapical process is most variable and may be insignificant, may be of equal length to the postcingular processes or may be longer than all others. Usually, the antapical process is noticeably narrower than the postcingular ones. Both epi- and hypocystal processes usually bear secondary tubules towards, but not at, their distal extremities. The archeopyle is single-paraplate precingular with or without splitting between apical and precingular paraplate series.
Affinities:
Silicisphaera Davey and Verdier, 1976 and Achilleodinium Eaton, 1976 are here considered to be junior synonyms of Florentinia Davey and Verdier, 1973.
In comparing the original generic descriptions of Florentinia and Silicisphaera, only one difference emerges as being important, that of the typical possession by Florentinia of "a distinctively large, tubular antapical process". In Silicisphaera, on the other hand, "the antapical process is not distinctive or particularly large". Having written this, however Davey and Verdier (1976, p. 326-327) illustrate a taxon termed Silicisphaera aff. ferox which certainly possesses a distinctive antapical process and, by their own definition, must be placed in Florentinia. On their range chart, Davey and Verdier (1976, p. 331) illustrate the range of the genus Silicisphaera as Turonian to Maastrichtian. Taxa observed in the present work, based on the presence or absence of a particularly large or distinctive antapical process, could have been placed either in Florentinia or Silicisphaera. The present author chooses to consider the variability of the antapical process to be an intrageneric feature.
Achilleodinium was erected by Eaton to include taxa basically similar to Hystrichokolpoma Klumpp, 1953 emend. Williams and Downie, 1966 but with a single-paraplate precingular archeopyle as opposed to the tetratabular apical one of the latter genus. Eaton compares Achilleodinium with Florentinia and states, "In Florentinia the archeopyle is formed by displacement of precingular plate 3`` with breakage or displacement of the apical plates". The original diagnosis of Florentinia includes the possibility of a single paraplate precingular (3``) archeopyle and therefore Eaton`s distinction of Achilleodinium from Florentinia is unfounded. Eaton (pers. comm.) has expressed reservations to Achilleodinium being synonymised with Florentinia on the grounds that there is a distinct stratigraphical gap between the highest records of Florentinia and the lowest occurrence of Achilleodinium. By implication, therefore, Achilleodinium may be unrelated to Florentinia and may exhibit homeomorphy. The present author views unfavourably the introduction of such a concept into what can only be a purely morphological classification system and Achilleodinium is therefore regarded here as a junior synonym of Florentinia.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Florentinia Davey and Verdier, 1973, emend. Duxbury, 1980. According to Duxbury (1980), this species is spheroidal to ellipsoidal, bearing large epi- and hypocystal processes which reflect a tabulation of 4`, 6", 5"' , 1"". Number of sulcal and cingular processes variable. The epi- and hypocystal process form is variable and ranges from single tubes which are open, partially closed or closed distally to process complexes composed of distally tapering, free-standing spines or tubules, which impart a complex appearance to the cyst but which nevertheless represent only a few processes. Some variation in process size is usually apparent with the order of increasing size being paracingular and parasulcal, apical, precingular and postcingular. The antapical is most variable and may be insignificant, may be of equal length to the postcingular processes, or may be longer than all the others. Usually the antapical process is narrower than the postcingulars. Both epi and hypocystal processes usually bear secondary tubules towards, but not at, their distal extremities. Archeopyle single precingular with or without splitting between apical and precingular paraplates.
[Florentinia, Davey and Verdier, 1973, p. 185–186; Emendation: Duxbury, 1980, p. 119-120
Type species: Florentinia laciniata, Davey and Verdier, 1973 (pl.2, figs.1,3)]
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Original description: [Davey and Verdier, 1973]:
Diagnosis:
The cysts are subspherical and bear one intratabular process per reflected plate area. The processes are hollow, apparently open distally and usually slightly fibrous. A distinctively large, tubular antapical process is typically present; it is usually open distally and may rarely give rise to secondary tubules distally. The pre- and postcingular processes are large, relatively wide proximally, and terminate distally with a simple funnel or a number of tubules. The apical processes are similar but generally smaller. The cingular and sulcal processes are finer, open distally and may be deeply furcate.
The reflected tabulation is 3-4`, 6``, 6c, 5```, 1p, 1```` and 2-5s.
The position of the archaeopyle is either precingular (3``), with sometimes an incipient apical-precingular tear, or is formed by the loss of the third precingular plate (3``) and the apical plates.
Affinities:
Florentinia differs from previously described genera by the possession of either a precingular or combination archaeopyle, a distinctive tubular antapical process and regularly arranged processes that are apparently open distally. The only closely related species to be described have been placed in the Tertiary genus Hystrichokolpoma Klumpp 1953; it is, in fact, considered that Florentinia is ancestral to Hystrichokolpoma. The two genera are basically similar, the main difference being that the latter genus possesses only an apical archaeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 155-156:
Synopsis:
Cysts skolochorate, body subspherical; paratabulation gonyaulacacean, indicated by intratabular processes of two sizes, with the narrower processes in paracingular and parasulcal areas; large distinctive antapical process typically present; archeopyle precingular, type P, or combination, Type tA+P.
Description:
Shape: Body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. intratabular processes hollow, smooth, or faintly striate, normally open distally; tips truncate or variously subdivided and may be drawn out into short tubules. Periphragm smooth or finely granulate.
Paratabulation: Indicated by intratabular processes; gonyaulacacean, formula: 3-4`, 6``, 6c, 5```, 1p, 1````, 2-5s. Postcingular paraplates interpreted as reflecting plates 2``` to 6```. Antapical process usually distinctly different from the others and may be closed distally.
Archeopyle: Either precingular, Type P (3`` only), with or without an incipient apical-precingular tear, or combination, Type tA+P; operculum free. Paracingulum: Indicated by six equatorial processes with transversely elongate bases and one or more tips.
Parasulcus: Indicated by two to five processes; anterior and posterior parasulcal processes of intermediate size and usually slightly wider than other parasulcal processes.
Size: Intermediate to large.
Affinities:
Florentinia differs from Silicisphaera in having a distinctively large antapical process, which Silicisphaera lacks, and in generally less complex processes in the precingular and postcingular series. Consistent separation of Florentinia and Silicisphaera may be difficult because of intergradational features. Florentinia differs from Hystrichokolpoma in having either a precingular or a combination archeopyle (Type tA+P) rather than an apical archeopyle (Type tA).
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Emended description:
Duxbury, 1980:
Diagnosis:
Spheroidal to ellipsoidal dinoflagellate cysts bearing large epi- and hypocystal processes which reflect a paratabulation of the formula 4`, 6``, 5```, 1````. There are a variable number of paracingular and parasulcal processes. The epi- and hypocystal process form is very variable and ranges from single tubes which are open, partially closed or closed distally to process complexes composed of distally tapering, free-standing spines or tubules which impart a complex appearance to the cyst but which nevertheless represent only a few processes. Some variation in process size is usually apparent with the order of increasing size being paracingular and parasulcal, apical, precingular and postcingular. The antapical process is most variable and may be insignificant, may be of equal length to the postcingular processes or may be longer than all others. Usually, the antapical process is noticeably narrower than the postcingular ones. Both epi- and hypocystal processes usually bear secondary tubules towards, but not at, their distal extremities. The archeopyle is single-paraplate precingular with or without splitting between apical and precingular paraplate series.
Affinities:
Silicisphaera Davey and Verdier, 1976 and Achilleodinium Eaton, 1976 are here considered to be junior synonyms of Florentinia Davey and Verdier, 1973.
In comparing the original generic descriptions of Florentinia and Silicisphaera, only one difference emerges as being important, that of the typical possession by Florentinia of "a distinctively large, tubular antapical process". In Silicisphaera, on the other hand, "the antapical process is not distinctive or particularly large". Having written this, however Davey and Verdier (1976, p. 326-327) illustrate a taxon termed Silicisphaera aff. ferox which certainly possesses a distinctive antapical process and, by their own definition, must be placed in Florentinia. On their range chart, Davey and Verdier (1976, p. 331) illustrate the range of the genus Silicisphaera as Turonian to Maastrichtian. Taxa observed in the present work, based on the presence or absence of a particularly large or distinctive antapical process, could have been placed either in Florentinia or Silicisphaera. The present author chooses to consider the variability of the antapical process to be an intrageneric feature.
Achilleodinium was erected by Eaton to include taxa basically similar to Hystrichokolpoma Klumpp, 1953 emend. Williams and Downie, 1966 but with a single-paraplate precingular archeopyle as opposed to the tetratabular apical one of the latter genus. Eaton compares Achilleodinium with Florentinia and states, "In Florentinia the archeopyle is formed by displacement of precingular plate 3`` with breakage or displacement of the apical plates". The original diagnosis of Florentinia includes the possibility of a single paraplate precingular (3``) archeopyle and therefore Eaton`s distinction of Achilleodinium from Florentinia is unfounded. Eaton (pers. comm.) has expressed reservations to Achilleodinium being synonymised with Florentinia on the grounds that there is a distinct stratigraphical gap between the highest records of Florentinia and the lowest occurrence of Achilleodinium. By implication, therefore, Achilleodinium may be unrelated to Florentinia and may exhibit homeomorphy. The present author views unfavourably the introduction of such a concept into what can only be a purely morphological classification system and Achilleodinium is therefore regarded here as a junior synonym of Florentinia.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Florentinia Davey and Verdier, 1973, emend. Duxbury, 1980. According to Duxbury (1980), this species is spheroidal to ellipsoidal, bearing large epi- and hypocystal processes which reflect a tabulation of 4`, 6", 5"' , 1"". Number of sulcal and cingular processes variable. The epi- and hypocystal process form is variable and ranges from single tubes which are open, partially closed or closed distally to process complexes composed of distally tapering, free-standing spines or tubules, which impart a complex appearance to the cyst but which nevertheless represent only a few processes. Some variation in process size is usually apparent with the order of increasing size being paracingular and parasulcal, apical, precingular and postcingular. The antapical is most variable and may be insignificant, may be of equal length to the postcingular processes, or may be longer than all the others. Usually the antapical process is narrower than the postcingulars. Both epi and hypocystal processes usually bear secondary tubules towards, but not at, their distal extremities. Archeopyle single precingular with or without splitting between apical and precingular paraplates.