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Spumadinium
From Williams et al., 2017:
[Spumadinium, Brinkhuis et al., 2000, p. 103, 105
Type species: Spumadinium felderorum, Brinkhuis et al., 2000 (pl.4, figs.10-12)]
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Original description [Brinkhuis, et al., 2000]:
Diagnosis:
A gonyaulacalean dinoflagellate cyst with a spongy periphragm from which arise processes, and combination archeopyle interpreted as being formed from the loss of two precingular paraplates (3″–4″) plus two anterior intercalary paraplates (1a–2a).
Description:
Spumadinium is a subspherical gonyaulacalean dinoflagellate cyst with a thin endophragm and spongy periphragm, possibly columellate, with a perforate outer surface bearing processes, which are short in Spumadinium felderorum. The archeopyle is unusual, being interpreted to have formed by the loss of two precingular paraplates (3″–4″) plus the two anterior intercalary paraplates (1a–2a, Fig. 3L). This deduction is based on the size and shape of the archeopyle, since the operculum or opercular pieces have not been identified. Apart from the archeopyle, the only other suggestion of tabulation is an alignment of the processes in the cingular region.
Remarks:
Several tabulation models were used in an attempt to elucidate the nature of the unusual archeopyle ( Fig. 3). We also considered several dinocysts with known hypocystal archeopyles including Caligodinium, Tuberculodinium and Capisocysta. Only the pareodinioid model with three apical and two anterior intercalary paraplates (as in species of Lacrymodinium Albert et al., 1986 of the family Pareodiniaceae) has a tabulation that seems to fit the archeopyle outline as shown in Plate VI(4) and Fig. 3L. By assuming that the two anterior intercalaries (1a and 2a) and two precingulars (3″ and 4″) are lost in formation of the archeopyle in Spumadinium, an outline is obtained that is almost identical to that of the observed archeopyle margin. Comparison of Spumadinium with other genera is difficult because of the uniqueness of the archeopyle. Nearly all combination archeopyles in the gonyaulacaleans are epicystal and there are no known genera with a combination archeopyle formed from the loss of two anterior intercalaries and two precingulars. Within the Pareodiniaceae, there is a variety of archeopyle types usually involving the dorsal anterior intercalary plates, although in a few genera the apicals alone or in combination with intercalary plates are lost. The archeopyle in Lacrymodinium results from the loss of two anterior intercalary plates. Because of the uniqueness of its archeopyle and the spongy periphragm, Spumadinium is questionably included in the family Pareodiniaceae of the suborder Cladopyxiineae.The possible affinity of Spumadinium with Lacrymodinium raises an interesting question concerning age. The single species of Lacrymodinium, Lacrymodinium warrenii, is known only from the Late Jurassic. Fensome et al. (1993) included Lacrymodinium in the subfamily Pareodinioideae of the family Pareodiniaceae. Representatives of the Pareodiniaceae occur almost exclusively in Jurassic and Cretaceous rocks. The presence of Spumadinium in the Late Maastrichtian–Paleocene would extend the last appearance for the family. The suborder in which the Pareodiniaceae are included, the Cladopyxiineae, are represented today by the Cladopyxiaceae. Two of the extant genera, Cladopyxis and Acanthodinium, are unusual in having spines. Genera included in this family have three or four anterior intercalary plates, rather than the two or three of the Pareodiniaceae, and the first apical is insert rather than exsert or metasert. A cyst stage in the living taxa of this suborder has not been observed.
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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.
Spumadinium Brinkhuis et al., 2000. Diagnosis. A gonyaulacalean dinoflagellate cyst with a combination archeopyle interpreted to be formed from the loss of two precingular plates (3"-4"0 plus two anterior intercalary plates.
[Spumadinium, Brinkhuis et al., 2000, p. 103, 105
Type species: Spumadinium felderorum, Brinkhuis et al., 2000 (pl.4, figs.10-12)]
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Original description [Brinkhuis, et al., 2000]:
Diagnosis:
A gonyaulacalean dinoflagellate cyst with a spongy periphragm from which arise processes, and combination archeopyle interpreted as being formed from the loss of two precingular paraplates (3″–4″) plus two anterior intercalary paraplates (1a–2a).
Description:
Spumadinium is a subspherical gonyaulacalean dinoflagellate cyst with a thin endophragm and spongy periphragm, possibly columellate, with a perforate outer surface bearing processes, which are short in Spumadinium felderorum. The archeopyle is unusual, being interpreted to have formed by the loss of two precingular paraplates (3″–4″) plus the two anterior intercalary paraplates (1a–2a, Fig. 3L). This deduction is based on the size and shape of the archeopyle, since the operculum or opercular pieces have not been identified. Apart from the archeopyle, the only other suggestion of tabulation is an alignment of the processes in the cingular region.
Remarks:
Several tabulation models were used in an attempt to elucidate the nature of the unusual archeopyle ( Fig. 3). We also considered several dinocysts with known hypocystal archeopyles including Caligodinium, Tuberculodinium and Capisocysta. Only the pareodinioid model with three apical and two anterior intercalary paraplates (as in species of Lacrymodinium Albert et al., 1986 of the family Pareodiniaceae) has a tabulation that seems to fit the archeopyle outline as shown in Plate VI(4) and Fig. 3L. By assuming that the two anterior intercalaries (1a and 2a) and two precingulars (3″ and 4″) are lost in formation of the archeopyle in Spumadinium, an outline is obtained that is almost identical to that of the observed archeopyle margin. Comparison of Spumadinium with other genera is difficult because of the uniqueness of the archeopyle. Nearly all combination archeopyles in the gonyaulacaleans are epicystal and there are no known genera with a combination archeopyle formed from the loss of two anterior intercalaries and two precingulars. Within the Pareodiniaceae, there is a variety of archeopyle types usually involving the dorsal anterior intercalary plates, although in a few genera the apicals alone or in combination with intercalary plates are lost. The archeopyle in Lacrymodinium results from the loss of two anterior intercalary plates. Because of the uniqueness of its archeopyle and the spongy periphragm, Spumadinium is questionably included in the family Pareodiniaceae of the suborder Cladopyxiineae.The possible affinity of Spumadinium with Lacrymodinium raises an interesting question concerning age. The single species of Lacrymodinium, Lacrymodinium warrenii, is known only from the Late Jurassic. Fensome et al. (1993) included Lacrymodinium in the subfamily Pareodinioideae of the family Pareodiniaceae. Representatives of the Pareodiniaceae occur almost exclusively in Jurassic and Cretaceous rocks. The presence of Spumadinium in the Late Maastrichtian–Paleocene would extend the last appearance for the family. The suborder in which the Pareodiniaceae are included, the Cladopyxiineae, are represented today by the Cladopyxiaceae. Two of the extant genera, Cladopyxis and Acanthodinium, are unusual in having spines. Genera included in this family have three or four anterior intercalary plates, rather than the two or three of the Pareodiniaceae, and the first apical is insert rather than exsert or metasert. A cyst stage in the living taxa of this suborder has not been observed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Spumadinium Brinkhuis et al., 2000. Diagnosis. A gonyaulacalean dinoflagellate cyst with a combination archeopyle interpreted to be formed from the loss of two precingular plates (3"-4"0 plus two anterior intercalary plates.