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Endoscrinium luridum
Endoscrinium luridum (Deflandre, 1939a, p.166, pl.5, figs.4-6) Gocht, 1970b, p.144-146.
Originally Gymnodinium (Appendix B), subsequently Scriniodinium, thirdly (and now) Endoscrinium, fourthly Tubotuberella. Lentin and Williams (1993, p.209) retained this species in Endoscrinium.
Holotype: Deflandre, 1939a, pl.5, figs.4-5; Jan du Chêne et al., 1986a, pl.109, figs.6-8.
Age: Early Oxfordian.
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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.
Endoscrinium luridum (Deflandre, 1938a) Gocht, 1970b, is similar to E.asymmetricum in having a winglike ventral area of the hypocyst, which projects over the antapical paraplate, which is ventral in position. However, in E.asymmetricum the lobes of the winglike hypocystal feature are markedly different in size, this disparity gives the distinctive asymmetrical dorso-ventral outline. E.asymmetricum is also more angular in outline and more elongate longitudinally than E.luridum. The only opening in the periphragm of E.luridum is the archeopyle. E.asymmetricum may also have one or two opisthopyles. Size: length of 107 µm, minimum of 49 µm. The holotype is 68 x 69 µm.
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Remark: Courtinat, 1989, p.216
The transfer by Davies (1983) is not adopted. The outline of the Tubotuberella forms is not the same as that of the Endoscrinium forms. The antapical paraplate in Tubotuberella possesses an opisthopyle in posterior position, whilst in Endoscrinium it is in anterior position. E. luridum has an opisthopyle in anterior position. The other characteristics of E. luridum are a type P/C apical, a type 1u/1i ventral, and a type gamma paratabulation, and a symmetrical antapical paraplate.
The crests are spinous; this morphological characteristic has been observed on the holotype.
Supplemental description: Pocock, 1972, p.91
Theca comprises an irregularly spheroidal capsule enclosed in a thin outer wall; dorsoventrally flattened; outer wall carries a fairly prominent transverse furrow; longitudinal furrow and plating obscure; tabulation indeterminate; hypothecal extension of outer wall asymmetric; extending about 6.0 Ám apically of the capsule; epithecal extensions double and of different sizes, extending about 3.0 Ám and 5.0 Ám apically of the capsule; archeopyle precingular; capsule about 1.0 Ám thick; smooth to scabrate; outer wall less than 0.5 Ám thick; smooth and transparent; color of capsule amber; length of theca 63.0 (72.3) 80.0 Ám; width of theca 55.0 (66.3) 74.0 Ám; length of capsule 48.0 (57.0) 63.0 Ám; width of capsule 40.0 (58.0) 62.0 Ám.
Affinities:
Pocock, 1972, p.91: This species appears to correspond closely with Deflandre's original description and figures of G. Iuridum, and with Sarjeant's photographs of specimens assigned to the same species. The grains assigned to S. Iuridum by Klement (1960, pp.21-22, pl.1, figs.2--3) may represent a distinct species.
Originally Gymnodinium (Appendix B), subsequently Scriniodinium, thirdly (and now) Endoscrinium, fourthly Tubotuberella. Lentin and Williams (1993, p.209) retained this species in Endoscrinium.
Holotype: Deflandre, 1939a, pl.5, figs.4-5; Jan du Chêne et al., 1986a, pl.109, figs.6-8.
Age: Early Oxfordian.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Endoscrinium luridum (Deflandre, 1938a) Gocht, 1970b, is similar to E.asymmetricum in having a winglike ventral area of the hypocyst, which projects over the antapical paraplate, which is ventral in position. However, in E.asymmetricum the lobes of the winglike hypocystal feature are markedly different in size, this disparity gives the distinctive asymmetrical dorso-ventral outline. E.asymmetricum is also more angular in outline and more elongate longitudinally than E.luridum. The only opening in the periphragm of E.luridum is the archeopyle. E.asymmetricum may also have one or two opisthopyles. Size: length of 107 µm, minimum of 49 µm. The holotype is 68 x 69 µm.
--------------------------------------------------
Remark: Courtinat, 1989, p.216
The transfer by Davies (1983) is not adopted. The outline of the Tubotuberella forms is not the same as that of the Endoscrinium forms. The antapical paraplate in Tubotuberella possesses an opisthopyle in posterior position, whilst in Endoscrinium it is in anterior position. E. luridum has an opisthopyle in anterior position. The other characteristics of E. luridum are a type P/C apical, a type 1u/1i ventral, and a type gamma paratabulation, and a symmetrical antapical paraplate.
The crests are spinous; this morphological characteristic has been observed on the holotype.
Supplemental description: Pocock, 1972, p.91
Theca comprises an irregularly spheroidal capsule enclosed in a thin outer wall; dorsoventrally flattened; outer wall carries a fairly prominent transverse furrow; longitudinal furrow and plating obscure; tabulation indeterminate; hypothecal extension of outer wall asymmetric; extending about 6.0 Ám apically of the capsule; epithecal extensions double and of different sizes, extending about 3.0 Ám and 5.0 Ám apically of the capsule; archeopyle precingular; capsule about 1.0 Ám thick; smooth to scabrate; outer wall less than 0.5 Ám thick; smooth and transparent; color of capsule amber; length of theca 63.0 (72.3) 80.0 Ám; width of theca 55.0 (66.3) 74.0 Ám; length of capsule 48.0 (57.0) 63.0 Ám; width of capsule 40.0 (58.0) 62.0 Ám.
Affinities:
Pocock, 1972, p.91: This species appears to correspond closely with Deflandre's original description and figures of G. Iuridum, and with Sarjeant's photographs of specimens assigned to the same species. The grains assigned to S. Iuridum by Klement (1960, pp.21-22, pl.1, figs.2--3) may represent a distinct species.