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Luxadinium propatulum
Luxadinium propatulum Brideaux and McIntyre, 1975
Holotype: C. Singh, 1971, pl.62, fig.8, as Scriniodinium eurypylum
Age: Albian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Luxadinium propatulum Brideaux and McIntyre, 1975, has a rounded to pentagonal pericyst prolonged into a short, conical blunt apical horn, and two unequal antapical horns. Endocyst almost filling pericyst but with apical and antapical pericoels. Cingulum laevo-rotatory. Periphragm sparsely ornamented with minute spines. Size: pericyst length 58-84 µm, width 40-60 µm, endocyst length 40-54 µm, width 37-58 µm.
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Luxadinium propatulum: Brideaux and McIntyre 1975, p. 37
The following new species is thus introduced: Luxadinium propatulum sp. nov., = Scriniodinium eurypylum auct. non Manum and Cookson, 1964 in Brideaux, 1971, p. 99, P1. 29, figs. 97, 98 and in Singh, 1971, p. 364, Pl. 62, figs. 6-10. The holotype chosen is the specimen illustrated in Singh (1971, Pl. 62, fig. 8); that specimen shows clearly an archeopyle formed by the loss of three reflected intercalary plates and three reflected precingular plates in both the periphragm and endophragm. The holotype comes from Sample No. 3-S-5, Section 3, of the lower Shaftesbury Formation (sec. 11, tp. 83, rge. 22, W5M, west-central Alberta) at the base of the measured section, and is found on Slide No. 3-S-5 Micro. 137 at co-ordinates 11.8 x 42.9 on the Carl Zeiss Polarizing Photomicroscope at the Research Council of Alberta, Edmonton, Alberta, Canada. The holotype specimen is refigured in this paper on Plate 13, figures 9-11 and a second specimen is figured on Plate 13, figure 12 and Plate 14, figures 1, 2.
Except for designation of the archeopyle form as consisting of 3I + 3P, or 3I3P, the descriptions and comments of the two authors (Brideaux, 1971b, p. 99; Singh 1971, p. 364, 365) suffice for other morphological details.
The assertion by Davey and Verdier (1973, p. 199 and p. 210) that the specimen illustrated as Scriniodinium eurypylum Manum and Cookson (= Luxadinium propatuZum sp. nov.) by Brideaux (1971b, Pl. 29, fig. 97) possesses an apical archeopyle and belongs to Ovoidinium verrucosum var. ostium Davey and Verdier, 1973, is incorrect. Davey (pers. com., 1974) agrees with this assessment. Furthermore, the range of Luxadinium propatulum sp. nov. does extend into the Cenomanian (unpublished data of the authors) contrary to the opinions expressed by Davey and Verdier (1973, p. 210). W.W. Brideaux has observed the species in Cenomanian material from Saskatchewan kindly loaned by R.J. Davey.
Other groups of peridinioid cysts, in which the operculum either remains attached (i.e.: 3I3Pa) or involves the additional loss of one or more reflected plates of the apical series, also exist (W.R. Evitt, pers. com.) and also show considerable variation in the form of the operculum. These groups include, in part, some species assigned to the genera, Palaeoperidinium Deflandre ex Sarjeant and Astrocysta Davey (see also Norris and Hedlund, 1972). W.R. Evitt (pers. com., 1973) plans a more comprehensive treatment of some or all of these forms, and the authors therefore propose no further changes in nomenclature and taxonomy in this contribution.
Holotype: C. Singh, 1971, pl.62, fig.8, as Scriniodinium eurypylum
Age: Albian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Luxadinium propatulum Brideaux and McIntyre, 1975, has a rounded to pentagonal pericyst prolonged into a short, conical blunt apical horn, and two unequal antapical horns. Endocyst almost filling pericyst but with apical and antapical pericoels. Cingulum laevo-rotatory. Periphragm sparsely ornamented with minute spines. Size: pericyst length 58-84 µm, width 40-60 µm, endocyst length 40-54 µm, width 37-58 µm.
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Luxadinium propatulum: Brideaux and McIntyre 1975, p. 37
The following new species is thus introduced: Luxadinium propatulum sp. nov., = Scriniodinium eurypylum auct. non Manum and Cookson, 1964 in Brideaux, 1971, p. 99, P1. 29, figs. 97, 98 and in Singh, 1971, p. 364, Pl. 62, figs. 6-10. The holotype chosen is the specimen illustrated in Singh (1971, Pl. 62, fig. 8); that specimen shows clearly an archeopyle formed by the loss of three reflected intercalary plates and three reflected precingular plates in both the periphragm and endophragm. The holotype comes from Sample No. 3-S-5, Section 3, of the lower Shaftesbury Formation (sec. 11, tp. 83, rge. 22, W5M, west-central Alberta) at the base of the measured section, and is found on Slide No. 3-S-5 Micro. 137 at co-ordinates 11.8 x 42.9 on the Carl Zeiss Polarizing Photomicroscope at the Research Council of Alberta, Edmonton, Alberta, Canada. The holotype specimen is refigured in this paper on Plate 13, figures 9-11 and a second specimen is figured on Plate 13, figure 12 and Plate 14, figures 1, 2.
Except for designation of the archeopyle form as consisting of 3I + 3P, or 3I3P, the descriptions and comments of the two authors (Brideaux, 1971b, p. 99; Singh 1971, p. 364, 365) suffice for other morphological details.
The assertion by Davey and Verdier (1973, p. 199 and p. 210) that the specimen illustrated as Scriniodinium eurypylum Manum and Cookson (= Luxadinium propatuZum sp. nov.) by Brideaux (1971b, Pl. 29, fig. 97) possesses an apical archeopyle and belongs to Ovoidinium verrucosum var. ostium Davey and Verdier, 1973, is incorrect. Davey (pers. com., 1974) agrees with this assessment. Furthermore, the range of Luxadinium propatulum sp. nov. does extend into the Cenomanian (unpublished data of the authors) contrary to the opinions expressed by Davey and Verdier (1973, p. 210). W.W. Brideaux has observed the species in Cenomanian material from Saskatchewan kindly loaned by R.J. Davey.
Other groups of peridinioid cysts, in which the operculum either remains attached (i.e.: 3I3Pa) or involves the additional loss of one or more reflected plates of the apical series, also exist (W.R. Evitt, pers. com.) and also show considerable variation in the form of the operculum. These groups include, in part, some species assigned to the genera, Palaeoperidinium Deflandre ex Sarjeant and Astrocysta Davey (see also Norris and Hedlund, 1972). W.R. Evitt (pers. com., 1973) plans a more comprehensive treatment of some or all of these forms, and the authors therefore propose no further changes in nomenclature and taxonomy in this contribution.