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Willeidinium
From Fensome et al., 2019:
Willeidinium, Feist-Burkhardt, 1995a, p.168,170–171
Type species: Willeidinium baiocassinum, Feist-Burkhardt, 1995a (pl.1, figs.1–3; text-fig.5, nos.1a–b)
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Original description: [Feist-Burkhardt, 1995a]:
Diagnosis:
Cysts proximate, subspherical, suturocavate. Paratabulation indicated by parasutural septa. Cyst surface between parasutures smooth or with features of low relief. Epicystal archeopyle, type Ea. Paratabulation derived gonyaulacacean, formula: ?2 pr, 3` [1`, 2`, 3`*(3.+4.)], 2a, 5" [1", 2", 3", 4", 5"*(5"+6")], 6c, 6"`, lp, 1"", 6s. Distalmost apical paraplate (3`) in contact with the anterior sulcal paraplate (as). Sinistrally contorted paraplate configuration.
Description:
Shape: Cysts proximate, subspherical.
Wall Relationships: Endophragm and periphragm closely appressed except for parasutural areas where the raised periphragm forms tunnel-like septa; suturocavate.
Wall Features: Parasutural septa present, entire or perforated, with smooth or denticulate crests. Surface between parasutural features smooth or with features of low relief.
Archeopyle: Epicystal, type Ed [= (tAtItP)a], operculum adnate; principal archeopyle suture anterior to paracingulum. Sometimes accessory sutures in peri- and endophragm formed between precingular paraplates.
Paratabulation: Entirely indicated by parasutural features; derived gonyaulacacean, formula: ?2 pr, 3` [1`, 2`, 3`*(3`+4`)],2a,5" [1",2",3",4",5"*(5``+6``],6c,6"`, lp,1"",6s (see Text-Figure 1). Distalmost apical paraplate (3`) very large and in contact with the anterior sulcal paraplate (as) (A/ai-arrangement of Helenes,1986), probably formed by fusion of standard gonyaulacalean 3` and 4`. Anterior intercalary homologue *2a large, reaching the apex. Distalmost precingular paraplate (5`) subplanate, very large and narrowing towards the parasulcus; probably formed by fusion of standard gonyaulacalean 5" and 6". Paraplate 4" camerate. Hypocystal paratabulation symmetrical sexiform. Boundary between 4"` and 5"` distal in location relative to the boundary between 3" and 4" (= sinistral torsion of Fensome et al., 1993). Paracingulum. Indicated by parasutural features, clearly subdivided; levorotatory.
Parasulcus: Clearly subdivided by parasutural features. L- type ventral organization with A/ai-arrangement.
Size: Intermediate.
Affinities/Comparison:
Willeidinium shows an unusual paratabulation pattern. Ctenidodinium Deflandre 1938 emend. Benson 1985, Dichadogonyaulax Sarjeant 1966 emend. Benson 1985 and Koryslocysta Woollam 1983 emend. Benson 1985 have a similar archeopyle type (Ea), but differ in having a typical gonyaulacacean paratabulation including four apical and six precingular paraplates. Species of Willeidinium may superficially resemble Gonyaulacysta centriconnata Riding 1983, or species of Leptodinium Klement 1960 emend. Stover & Evitt 1978 and Impagidinium Stover & Evitt 1978, but they differ in paratabulation and in archeopyle type. Gonyaulacysta, Leptodinium and Impagidinium have a precingular archeopyle, type P (3").
Pentadinium Gerlach 1961 was originally described as having only five precingular paraplates, but re-examination of the type material by Benedek et al. (1982, p. 270) revealed the presence of six precingular paraplates. The extant dinoflagellate genus Ceratocorys Stein 1886 has five precingularplates, four apical homologues, and no anterior intercalary plates. The sixth precingular homologue contacts the first precingular plate and prevents contact of the anterior sulcal with any of the apical plates (Text-Figure 4). Additionally Ceratocorys differs from Willeidinium in its distinctive general morphology (see discussion below).
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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.
Willeidinium, Feist-Burkhardt, 1995a. Diagnosis from Feist-Burkhardt (1995a), cysts proximate, subspherical, suturocavate. Paratabulation indicated by parasutural septa. Cyst surface between parasutures smooth or with features of low relief. Epicystal archeopyle, type E@. Paratabulation derived gonyaulacacean, formula: ?2pr, 3` [1`,2`,3`(3`=4`)], 2a, 5` [1",2",3",4",5"(5"+6")], 6c, 6"' , 1p, 1"'' , 6s. Distalmost apical paraplate (3`) in contact with the anterior sulcal paraplate (as). Sinistrally contorted paraplate configuration. This genus differs from Ceratocorys in which the 6" contacts the 1" and prevents contact of the anterior sulcal with any of the apical plates.
Willeidinium, Feist-Burkhardt, 1995a, p.168,170–171
Type species: Willeidinium baiocassinum, Feist-Burkhardt, 1995a (pl.1, figs.1–3; text-fig.5, nos.1a–b)
----------------------------------------------------------------------------------------------------------------------------------
Original description: [Feist-Burkhardt, 1995a]:
Diagnosis:
Cysts proximate, subspherical, suturocavate. Paratabulation indicated by parasutural septa. Cyst surface between parasutures smooth or with features of low relief. Epicystal archeopyle, type Ea. Paratabulation derived gonyaulacacean, formula: ?2 pr, 3` [1`, 2`, 3`*(3.+4.)], 2a, 5" [1", 2", 3", 4", 5"*(5"+6")], 6c, 6"`, lp, 1"", 6s. Distalmost apical paraplate (3`) in contact with the anterior sulcal paraplate (as). Sinistrally contorted paraplate configuration.
Description:
Shape: Cysts proximate, subspherical.
Wall Relationships: Endophragm and periphragm closely appressed except for parasutural areas where the raised periphragm forms tunnel-like septa; suturocavate.
Wall Features: Parasutural septa present, entire or perforated, with smooth or denticulate crests. Surface between parasutural features smooth or with features of low relief.
Archeopyle: Epicystal, type Ed [= (tAtItP)a], operculum adnate; principal archeopyle suture anterior to paracingulum. Sometimes accessory sutures in peri- and endophragm formed between precingular paraplates.
Paratabulation: Entirely indicated by parasutural features; derived gonyaulacacean, formula: ?2 pr, 3` [1`, 2`, 3`*(3`+4`)],2a,5" [1",2",3",4",5"*(5``+6``],6c,6"`, lp,1"",6s (see Text-Figure 1). Distalmost apical paraplate (3`) very large and in contact with the anterior sulcal paraplate (as) (A/ai-arrangement of Helenes,1986), probably formed by fusion of standard gonyaulacalean 3` and 4`. Anterior intercalary homologue *2a large, reaching the apex. Distalmost precingular paraplate (5`) subplanate, very large and narrowing towards the parasulcus; probably formed by fusion of standard gonyaulacalean 5" and 6". Paraplate 4" camerate. Hypocystal paratabulation symmetrical sexiform. Boundary between 4"` and 5"` distal in location relative to the boundary between 3" and 4" (= sinistral torsion of Fensome et al., 1993). Paracingulum. Indicated by parasutural features, clearly subdivided; levorotatory.
Parasulcus: Clearly subdivided by parasutural features. L- type ventral organization with A/ai-arrangement.
Size: Intermediate.
Affinities/Comparison:
Willeidinium shows an unusual paratabulation pattern. Ctenidodinium Deflandre 1938 emend. Benson 1985, Dichadogonyaulax Sarjeant 1966 emend. Benson 1985 and Koryslocysta Woollam 1983 emend. Benson 1985 have a similar archeopyle type (Ea), but differ in having a typical gonyaulacacean paratabulation including four apical and six precingular paraplates. Species of Willeidinium may superficially resemble Gonyaulacysta centriconnata Riding 1983, or species of Leptodinium Klement 1960 emend. Stover & Evitt 1978 and Impagidinium Stover & Evitt 1978, but they differ in paratabulation and in archeopyle type. Gonyaulacysta, Leptodinium and Impagidinium have a precingular archeopyle, type P (3").
Pentadinium Gerlach 1961 was originally described as having only five precingular paraplates, but re-examination of the type material by Benedek et al. (1982, p. 270) revealed the presence of six precingular paraplates. The extant dinoflagellate genus Ceratocorys Stein 1886 has five precingularplates, four apical homologues, and no anterior intercalary plates. The sixth precingular homologue contacts the first precingular plate and prevents contact of the anterior sulcal with any of the apical plates (Text-Figure 4). Additionally Ceratocorys differs from Willeidinium in its distinctive general morphology (see discussion below).
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Willeidinium, Feist-Burkhardt, 1995a. Diagnosis from Feist-Burkhardt (1995a), cysts proximate, subspherical, suturocavate. Paratabulation indicated by parasutural septa. Cyst surface between parasutures smooth or with features of low relief. Epicystal archeopyle, type E@. Paratabulation derived gonyaulacacean, formula: ?2pr, 3` [1`,2`,3`(3`=4`)], 2a, 5` [1",2",3",4",5"(5"+6")], 6c, 6"' , 1p, 1"'' , 6s. Distalmost apical paraplate (3`) in contact with the anterior sulcal paraplate (as). Sinistrally contorted paraplate configuration. This genus differs from Ceratocorys in which the 6" contacts the 1" and prevents contact of the anterior sulcal with any of the apical plates.