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Gardodinium
From Williams et al., 2017:
[Gardodinium, Alberti, 1961, p. 18; Emendation: Harding, 1996, p. 358
Tax. sr. syn.: Chlamydophorella, by implication in Davey (1978, p.893), who transferred the "type species" of Gardodinium, Gardodinium trabeculosum, to Chlamydophorella — however, Lentin and Williams (1981, p.108; 1989, p.143) retained Gardodinium.
Type species: originally as Gardodinium eisenackii, Alberti, 1961 (pl.3, fig.11)] ; Gardodinium trabeculosum, emend. Harding 1996
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Original description: [Alberti, 1961]: (Translation: Stover and Evitt, 1978, p. 48):
Diagnosis:
Shell dorso-ventrally flattened, outline rounded-polygonal to oval. With a more or less long apical process which is often open. Transverse furrow slightly to moderately depressed, longitudinal furrow now and again delicately delimited from the epithecal and hypothecal plates. With a well-fitting inner capsule following the outline of the plates, from whose surface arise numerous, thin, usually forked septae whose outer ends touch the plates. Less often the ends of the septae are unforked and terminate in a point. Inner capsule with a knoblike apical projection, which is more or less distinct and projects slightly into the apical horn.
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Modified description:
Stover and Evitt 1978, p. 48-49:
Synopsis:
Cysts holocavate, subspherical; ectophragm forms prominent apical horn and is supported elsewhere by numerous slender projections arising from the autophragm; archeopyle apical, Type tA.
Description:
Shape: Subspherical with prominent apical horn.
Wall relationships: Cysts holocavate; autophragm may have short apical protrusion and ectophragm forms prominent apical horn.
Wall features: Definitive parasutural features lacking. Autophragm with numerous slender projections, solid or hollow, that may be slightly flared distally; projections of approximately uniform height support faintly ornamented ectophragm.
Paratabulation: Indicated by archeopyle and paracingulum; other indications, faint or inconsistent, include alignment of slender projections and linear markings on the ectophragm; formula unknown.
Archeopyle: Apical, Type tA; operculum free, but commonly in place. Paracingulum: Commonly indicated on ectophragm by faint, parallel parasutural features or by a shallow concavity seen most clearly at the lateral margins.
Parasulcus: Occasionally expressed as a less densely ornamented area on the autophragm or as a slightly depressed area on the ectophragm.
Size: Small to intermediate.
Affinities:
Gardodinium differs from Chlamydophorella in always having a prominent apical horn, in having more slender, delicate, less densely distributed projections, and in showing faint indications of paratabulation other than the archeopyle.
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Emended description:
Harding, 1996:
Diagnosis:
Dinoflagellate cysts consisting of an autophragm bearing solid, slender processes supporting a thin ectophragm which is developed into a parallel sided, elongate apical horn. Archaeopyle involves apical paraplates (plus incidental K, where discernible). Where developed, paratabulation is of leptodinioidean type, either expressed as low parasutural ridges on the ectophragm or by the alignment of penitabular autophragmal processes.
Remarks:
In 1959 Gocht gave an extremely detailed description of a new species of dinocyst from the late Hauterivian of the Friedeburg 3 borehole in Germany. Gocht named this species Scriniodinium trabeculosum. This description was based on five complete and two partial specimens, all of which showed dorso-ventral flattening (Gocht, 1959, p. 62). Two years later, Alberti (1961) erected the new genus Gardodinium, typified by the type specimen of Gocht`s species. At the same time Alberti (1961) described another species, Gardodinium eisenacki.
The concept of the genus Gardodinium has been problematical. Brideaux (1971, p.98) first questioned the distinctiveness of the genus Gardodinium, having noted close similarities to Chlamydophorella Cookson and Eisenack, 1958, observing that "should both genera prove to have apical archeopyles, it would be difficult to maintain two different names for the same concept". Both of these genera show a similar relationship between the process-bearing autophragm and the thin ectophragm, although species of Chlamydophorella do not show the elongate apical horn described for Gardodinium. This distinction, in addition to the less densely distributed and more delicate, slender processes, and faint indications of paratabulation on the latter genus led Stover and Evitt (1978) to retain Gardodinium. However, Davey (1978, p. 893) formally synonymised Gardodinium with Chlamydophorella, stating that the specimens of Gardodinium trabeculosum which he isolated from the Speeton Clay (Davey, 1974) clearly showed an apical archaeopyle, the same archaeopyle type found in Chlamydophorella. This synonymy was rejected by Lentin and Williams (1981, p. 108).
With the publication of his work on the Aptian and Albian dinocysts of the Isle of Wight, Duxbury (1983, p. 41), also believed that it was impossible to maintain the two genera as distinct entities. The synonymy was then adopted by Lentin and Williams (1985, p. 141). Other publications have reverted back to viewing Gardodinium as a separate and distinctive genus (Backhouse, 1987, p. 216; Stover and Helby, 1987, p. 107). Stover and Helby (1987, p. 107) distinguished the genus Gardodinium from Chlamydophorella by " 1, the prominent, almost parallel-sided apical horn of the former; 2, by the more elongate body of the former and 3, by the common arrangement of autophragm processes into fields defined by penitabular alignment". There is no evidence in the papers cited above that any of the foregoing authors examined the type specimen for the genus Gardodinium before making their recommendations. However, the evidence presented in this paper supports the view of these latter authors. In addition, although not a character of generic importance, observations made for this study have revealed that the ectophragm in many species referable to Chlamydophorella is far less robust and bears larger perforations than that in Gardodinium.
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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.
Gardodinium Alberti, 1961, emend. Harding, 1996. As emended by Harding (1996, p.358), Gardodinium has an autophragm bearing solid, slender processes supporting a thin ectophragm, which is developed into a parallel sided elongate apical horn. Archeopyle involves apical paraplates, plus the incidental K paraplate where discernible. Where developed, paratabulation is of leptodinioidean type, either expressed as low parasutural ridges on the ectophragm or by the alignment of penitabular autophragmal processes. Gardodinium differs from Chlamydophorella in the prominent, almost parallel sided, apical horn, the more elongate body, and the common arrangement of autophragm processes into fields defined by penitabular arrangement.
[Gardodinium, Alberti, 1961, p. 18; Emendation: Harding, 1996, p. 358
Tax. sr. syn.: Chlamydophorella, by implication in Davey (1978, p.893), who transferred the "type species" of Gardodinium, Gardodinium trabeculosum, to Chlamydophorella — however, Lentin and Williams (1981, p.108; 1989, p.143) retained Gardodinium.
Type species: originally as Gardodinium eisenackii, Alberti, 1961 (pl.3, fig.11)] ; Gardodinium trabeculosum, emend. Harding 1996
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Alberti, 1961]: (Translation: Stover and Evitt, 1978, p. 48):
Diagnosis:
Shell dorso-ventrally flattened, outline rounded-polygonal to oval. With a more or less long apical process which is often open. Transverse furrow slightly to moderately depressed, longitudinal furrow now and again delicately delimited from the epithecal and hypothecal plates. With a well-fitting inner capsule following the outline of the plates, from whose surface arise numerous, thin, usually forked septae whose outer ends touch the plates. Less often the ends of the septae are unforked and terminate in a point. Inner capsule with a knoblike apical projection, which is more or less distinct and projects slightly into the apical horn.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 48-49:
Synopsis:
Cysts holocavate, subspherical; ectophragm forms prominent apical horn and is supported elsewhere by numerous slender projections arising from the autophragm; archeopyle apical, Type tA.
Description:
Shape: Subspherical with prominent apical horn.
Wall relationships: Cysts holocavate; autophragm may have short apical protrusion and ectophragm forms prominent apical horn.
Wall features: Definitive parasutural features lacking. Autophragm with numerous slender projections, solid or hollow, that may be slightly flared distally; projections of approximately uniform height support faintly ornamented ectophragm.
Paratabulation: Indicated by archeopyle and paracingulum; other indications, faint or inconsistent, include alignment of slender projections and linear markings on the ectophragm; formula unknown.
Archeopyle: Apical, Type tA; operculum free, but commonly in place. Paracingulum: Commonly indicated on ectophragm by faint, parallel parasutural features or by a shallow concavity seen most clearly at the lateral margins.
Parasulcus: Occasionally expressed as a less densely ornamented area on the autophragm or as a slightly depressed area on the ectophragm.
Size: Small to intermediate.
Affinities:
Gardodinium differs from Chlamydophorella in always having a prominent apical horn, in having more slender, delicate, less densely distributed projections, and in showing faint indications of paratabulation other than the archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Harding, 1996:
Diagnosis:
Dinoflagellate cysts consisting of an autophragm bearing solid, slender processes supporting a thin ectophragm which is developed into a parallel sided, elongate apical horn. Archaeopyle involves apical paraplates (plus incidental K, where discernible). Where developed, paratabulation is of leptodinioidean type, either expressed as low parasutural ridges on the ectophragm or by the alignment of penitabular autophragmal processes.
Remarks:
In 1959 Gocht gave an extremely detailed description of a new species of dinocyst from the late Hauterivian of the Friedeburg 3 borehole in Germany. Gocht named this species Scriniodinium trabeculosum. This description was based on five complete and two partial specimens, all of which showed dorso-ventral flattening (Gocht, 1959, p. 62). Two years later, Alberti (1961) erected the new genus Gardodinium, typified by the type specimen of Gocht`s species. At the same time Alberti (1961) described another species, Gardodinium eisenacki.
The concept of the genus Gardodinium has been problematical. Brideaux (1971, p.98) first questioned the distinctiveness of the genus Gardodinium, having noted close similarities to Chlamydophorella Cookson and Eisenack, 1958, observing that "should both genera prove to have apical archeopyles, it would be difficult to maintain two different names for the same concept". Both of these genera show a similar relationship between the process-bearing autophragm and the thin ectophragm, although species of Chlamydophorella do not show the elongate apical horn described for Gardodinium. This distinction, in addition to the less densely distributed and more delicate, slender processes, and faint indications of paratabulation on the latter genus led Stover and Evitt (1978) to retain Gardodinium. However, Davey (1978, p. 893) formally synonymised Gardodinium with Chlamydophorella, stating that the specimens of Gardodinium trabeculosum which he isolated from the Speeton Clay (Davey, 1974) clearly showed an apical archaeopyle, the same archaeopyle type found in Chlamydophorella. This synonymy was rejected by Lentin and Williams (1981, p. 108).
With the publication of his work on the Aptian and Albian dinocysts of the Isle of Wight, Duxbury (1983, p. 41), also believed that it was impossible to maintain the two genera as distinct entities. The synonymy was then adopted by Lentin and Williams (1985, p. 141). Other publications have reverted back to viewing Gardodinium as a separate and distinctive genus (Backhouse, 1987, p. 216; Stover and Helby, 1987, p. 107). Stover and Helby (1987, p. 107) distinguished the genus Gardodinium from Chlamydophorella by " 1, the prominent, almost parallel-sided apical horn of the former; 2, by the more elongate body of the former and 3, by the common arrangement of autophragm processes into fields defined by penitabular alignment". There is no evidence in the papers cited above that any of the foregoing authors examined the type specimen for the genus Gardodinium before making their recommendations. However, the evidence presented in this paper supports the view of these latter authors. In addition, although not a character of generic importance, observations made for this study have revealed that the ectophragm in many species referable to Chlamydophorella is far less robust and bears larger perforations than that in Gardodinium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Gardodinium Alberti, 1961, emend. Harding, 1996. As emended by Harding (1996, p.358), Gardodinium has an autophragm bearing solid, slender processes supporting a thin ectophragm, which is developed into a parallel sided elongate apical horn. Archeopyle involves apical paraplates, plus the incidental K paraplate where discernible. Where developed, paratabulation is of leptodinioidean type, either expressed as low parasutural ridges on the ectophragm or by the alignment of penitabular autophragmal processes. Gardodinium differs from Chlamydophorella in the prominent, almost parallel sided, apical horn, the more elongate body, and the common arrangement of autophragm processes into fields defined by penitabular arrangement.