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Lasagniella
From Williams et al., 2017:
[Lasagniella, Brinkhuis et al., 2000, p. 101
Type species: Lasagniella herngreenii, Brinkhuis et al., 2000 (pl. 1, figs. 11-13)]
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Original description: [Brinkhuis et al., 2000]:
Diagnosis:
A proximate cavate dinoflagellate cyst with a combination A3I3P archeopyle and four or more wall layers.
Description:
Cyst proximate, subspherical to ovoidal or rhomboidal, with four to eight wall layers. The innermost layer is usually subspherical. The walls are separated by columellae, which are longer towards the apex, thus forming an apical horn. In the vicinity of the cingulum, the columellae are ca. 1 μm long. The cingulum and sulcus are faintly indicated on some specimens. The combination archeopyle is formed from the loss of one apical (3′), three anterior intercalary (1a–3a) and three precingular (3″–5″) paraplates. No complete operculum has been identified, suggesting that it may be compound, breaking up into individual paraplates, and that opercular pieces have been lost through sieving.
Remarks:
The archeopyle in L. herngreenii is interpreted as a combination archeopyle, based on the angularity of the margin shown in several specimens. The most plausible explanation is that three precingular (3″–5″), three anterior intercalary (1a–3a) and one apical paraplates are lost, with the third apical being at 6 O'clock in the specimens shown in Plate II(7). Thus, Lasagniella must be regarded as a peridinialean. Although the wall structure is more suggestive of a gonyaulacalean, it is impossible to duplicate the archeopyle margin on a gonyaulacalean tabulation. Multi-layered walls are uncommon in dinoflagellate cysts and no forms with eight layers have been described. Cepadinium Duxbury 1983 has up to four wall layers, but these are not columellate. Spongodinium Deflandre 1936 and Samlandia Eisenack 1954 have columellate walls, but these are gonyaulacalean genera with precingular archeopyles.
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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.
Lasagniella Brinkhuis et al., 2001, is a proximate dinocyst with a combination A3I3P archeopyle and four or more wall layers.
[Lasagniella, Brinkhuis et al., 2000, p. 101
Type species: Lasagniella herngreenii, Brinkhuis et al., 2000 (pl. 1, figs. 11-13)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Brinkhuis et al., 2000]:
Diagnosis:
A proximate cavate dinoflagellate cyst with a combination A3I3P archeopyle and four or more wall layers.
Description:
Cyst proximate, subspherical to ovoidal or rhomboidal, with four to eight wall layers. The innermost layer is usually subspherical. The walls are separated by columellae, which are longer towards the apex, thus forming an apical horn. In the vicinity of the cingulum, the columellae are ca. 1 μm long. The cingulum and sulcus are faintly indicated on some specimens. The combination archeopyle is formed from the loss of one apical (3′), three anterior intercalary (1a–3a) and three precingular (3″–5″) paraplates. No complete operculum has been identified, suggesting that it may be compound, breaking up into individual paraplates, and that opercular pieces have been lost through sieving.
Remarks:
The archeopyle in L. herngreenii is interpreted as a combination archeopyle, based on the angularity of the margin shown in several specimens. The most plausible explanation is that three precingular (3″–5″), three anterior intercalary (1a–3a) and one apical paraplates are lost, with the third apical being at 6 O'clock in the specimens shown in Plate II(7). Thus, Lasagniella must be regarded as a peridinialean. Although the wall structure is more suggestive of a gonyaulacalean, it is impossible to duplicate the archeopyle margin on a gonyaulacalean tabulation. Multi-layered walls are uncommon in dinoflagellate cysts and no forms with eight layers have been described. Cepadinium Duxbury 1983 has up to four wall layers, but these are not columellate. Spongodinium Deflandre 1936 and Samlandia Eisenack 1954 have columellate walls, but these are gonyaulacalean genera with precingular archeopyles.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lasagniella Brinkhuis et al., 2001, is a proximate dinocyst with a combination A3I3P archeopyle and four or more wall layers.