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Kallosphaeridium
From Fensome et al., 2019:
Kallosphaeridium, de Coninck, 1969, p.44.
Emendations: Jan du Chêne et al., 1985a, p.8–9; Wood et al., 2016, p.77–78.
Type: de Coninck, 1969, pl.13, figs.14–15, as Kallosphaeridium brevibarbatum.
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Original description: [De Coninck, 1969]:
Description:
Somewhat globular dinoflagellate cyst having an apical archeopyle with an attached operculum. The accessory sutures, when present, indicate six precingular plates from which the operculum detaches. It does not have other traces of tabulation. Hairs may ornament the shell.
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Modified description:
Stover and Evitt, 1978, p. 59:
Synopsis:
Cysts subspherical and without ridges, septa, or processes; indications of paratabulation, other than archeopyle, absent or expressed faintly and incompletely by parasutural alignment of ornamentation; autophragm smooth or variously ornamented with features of low relief; archeopyle apical, Type (tA)a.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: Parasutural features generally absent; some ornamentation may be aligned in rows. Autophragm smooth, granulate, hirsute, tuberculate, or with short spines.
Paratabulation: Normally indicated by archeopyle only.
Archeopyle: Apical, Type tAa; principal archeopyle suture zigzag; operculum attached, constituent paraplates typically undifferentiated .
Paracingulum: Not indicated or expressed by the transverse alignment of ornamentation.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Kallosphaeridium differs from Batiacasphaera in having an attached rather than a free operculum.
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Emended description:
Jan du Chêne et al., 1985:
Diagnosis:
Cyst proximate, subsphaerical, without processes, septa or prominent ridges; body composed of endophragm and periphragm or undifferentiated autophragm only; body variously ornamented with features of low to moderate relief, ornamentation the same or of two different types on individual specimens; archaeopyle type (4AI)@ and (5A)@, operculum typically small relative to cyst diameter, OW/CD ratio 0.5 or less; paratabulation indicated by principal and accessory archaeopyle sutures only, additional and rarely by low parasutural features; formula for epicyst: 0-2pr?, 4`, 1a, 6``, or 0-2pr?, 5`, 6``, hypocystal paratabulation not indicated.
Description:
Shape: Subsphaerical, nearly circular outline commonly modified by folding.
Wall relationships: Appressed endophragm and periphragm or undifferentiated autophragm; periphragm may be appreciably thicker than endophragm.
Wall features: Body uniformly ornamented with one or two types of features - punctoreticulate, granulate, finely hirsute, conate, clavate, spinate - which may be densely arranged or scatterd. Low parasutural features may be present on the epicyst.
Archaeopyle: Types (4AI)@ or (5A)@, principal archaeopyle suture zigzag, accessory archaeopyle sutures rarely absent. Operculum typically small relative to cyst diameter, OW/CD ratio less than 0.5, usually between 0.4 and 0.4.
Paratabulation: Expressed mainly by archaeopyle suture, rarely and additionally by generally incomplete parasutural features on opercula; formula for epicyst: 0-2pr?, 4`, 1a, 6`` or, 0-2 pr?, 5`, 6``; paratabulation for hypocyst not known.
Paracingulum: Not indicated or expressed occasionally by vague alignment of ornamentation features in the equatorial area.
Parasulcus: Not indicared.
Size: Small to intermediate, about 40 - 70 µm in diameter.
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Emended diagnosis Wood et al., 2016:
Emended diagnosis: Acavate, subspheroidal to ovoidal, nontabulate, proximate–proximochorate cysts, psilate or bearing ornamentation of low to moderate relief. The archaeopyle is apical or combination, type (5A)@ or type (4A1I)@, with an attached operculum.
Emended description: Proximate to proximochorate acavate dinoflagellate cysts with a subspheroidal to ovoidal central body. The autophragm may either be psilate or bear nontabular elements of low to moderate relief. The archaeopyle involves the four standard gonyaulacalean apical plates plus an additional single dorsal plate that may ormay not reach the apex. Thus the archaeopyle can be interpreted as type (5A)@ or type (4A1I)@; the operculumis attached ventrally,with deep accessory archaeopyle sutures between the six precingular plates typically present. The archaeopyle and operculumare relatively narrow; the overall operculum width/cyst diameter (OW/CD) is b0.5 and normally between 0.4 and 0.3.
Comments: The principal characteristics of Kallosphaeridiumare the small, ventrally attached operculum and the five-plate archaeopyle with associated accessory archaeopyle sutures. In well-preserved specimens, the middorsal 1a/3′ plate should be readily observable from the outline of the operculum. The operculum tends to be narrow relative to the overall cyst diameter. Kallosphaeridium is largely speciated on the nature of its ornamentation, the most variable featurewithin the genus. In terms of the standard gonyaulacalean tabulation, the five plates involved in the archaeopyle include the four standard apicals, homologues 1′ to 4′, plus a smaller dorsal plate, inserted partially or perhaps sometimes wholly between the second and third apical homologues. The additional plate may be a homologue of one of the small dorsal anterior intercalary plates (so-called K plates of Evitt, 1985; see also Fensome et al., 1993, figs. 84–85) of some gonyaulacaceans.
The emendation by Jan du Chêne et al. (1985, p. 8–9) provided more details than were given by de Coninck (1969), especially with regard to the archaeopyle and tabulation. Jan du Chêne et al. (1985, fig. 2.) discussed the overall operculum width/cyst diameter (OW/CD) in Kallosphaeridium. Cysts in this genus consistently have a relatively small archaeopyle and operculum; Jan du Chêne et al. (1985) noted that the OW/CD ratio is b0.5, and typically between 0.4 and 0.3.
Twenty-one species of Kallosphaeridiumwere listed by Fensome and Williams (2004, p. 375–377). Of these, we consider six to be accepted species and six to be provisional; these are included belowin the species lists as well as in Table 2. All six unequivocal species of Kallosphaeridium are of Palaeogene age and fromthe North Atlantic region. Of the six provisional species, the type material of Kallosphaeridium? orchiesense is also Palaeogene (Eocene), while the other five questionable species were described from the Mesozoic of Australia and Europe (Table 2). Fensome et al. (1993) assigned Kallosphaeridiumquestionably to the subfamily Cribroperidinioideae, but for reasons discussed under Phylogenetic affinities below, we prefer to leave its subfamilial affinity as uncertain.
Comparison: Kallosphaeridium is characterised by its relatively small operculum, attached ventrally, and the five-plate archaeopyle consistently with accessory archaeopyle sutures. The archaeopyle was interpreted to be apical (5A)@, or a combination apical (4A1I)@ by Jan du Chêne et al. (1985). The evidence for the five plate archaeopyle is the marked angulation in the middorsal area (Jan du Chêne et al., 1985, fig. 1A–B). The additional dorsal plate was interpreted as either the 1a or the 3′ plate by these authors. No other genus in the Sentusidinium complex has a five plate archaeopyle.
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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.
Kallosphaeridium de Coninck, 1969, emend. Jan du Chêne et al., 1985a, was emended by Jan du Chêne et al. (1985a, p.8) as follows, cysts proximate, subspherical, without processes, septa or prominent ridges; body composed of endophragm and periphragm or undifferentiated autophragm; body variously ornamented with features of low to moderate relief, ornamentation the same or of two different types on individual specimens; archeopyle type [4AI]@ or [5A]@, operculum typically small relative to cyst diameter, OW/CD ratio 0.5 or less; paratabulation indicated generally by principal and accessory archeopyle sutures only, additionally and rarely by low parasutural features; formula for epicyst 0-2pr?, 4`, 1a, 6", or 0-2pr?, 5`, 6", hypocystal paratabulation not indicated.
Kallosphaeridium, de Coninck, 1969, p.44.
Emendations: Jan du Chêne et al., 1985a, p.8–9; Wood et al., 2016, p.77–78.
Type: de Coninck, 1969, pl.13, figs.14–15, as Kallosphaeridium brevibarbatum.
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Original description: [De Coninck, 1969]:
Description:
Somewhat globular dinoflagellate cyst having an apical archeopyle with an attached operculum. The accessory sutures, when present, indicate six precingular plates from which the operculum detaches. It does not have other traces of tabulation. Hairs may ornament the shell.
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Modified description:
Stover and Evitt, 1978, p. 59:
Synopsis:
Cysts subspherical and without ridges, septa, or processes; indications of paratabulation, other than archeopyle, absent or expressed faintly and incompletely by parasutural alignment of ornamentation; autophragm smooth or variously ornamented with features of low relief; archeopyle apical, Type (tA)a.
Description:
Shape: Subspherical.
Wall relationships: Autophragm only.
Wall features: Parasutural features generally absent; some ornamentation may be aligned in rows. Autophragm smooth, granulate, hirsute, tuberculate, or with short spines.
Paratabulation: Normally indicated by archeopyle only.
Archeopyle: Apical, Type tAa; principal archeopyle suture zigzag; operculum attached, constituent paraplates typically undifferentiated .
Paracingulum: Not indicated or expressed by the transverse alignment of ornamentation.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Kallosphaeridium differs from Batiacasphaera in having an attached rather than a free operculum.
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Emended description:
Jan du Chêne et al., 1985:
Diagnosis:
Cyst proximate, subsphaerical, without processes, septa or prominent ridges; body composed of endophragm and periphragm or undifferentiated autophragm only; body variously ornamented with features of low to moderate relief, ornamentation the same or of two different types on individual specimens; archaeopyle type (4AI)@ and (5A)@, operculum typically small relative to cyst diameter, OW/CD ratio 0.5 or less; paratabulation indicated by principal and accessory archaeopyle sutures only, additional and rarely by low parasutural features; formula for epicyst: 0-2pr?, 4`, 1a, 6``, or 0-2pr?, 5`, 6``, hypocystal paratabulation not indicated.
Description:
Shape: Subsphaerical, nearly circular outline commonly modified by folding.
Wall relationships: Appressed endophragm and periphragm or undifferentiated autophragm; periphragm may be appreciably thicker than endophragm.
Wall features: Body uniformly ornamented with one or two types of features - punctoreticulate, granulate, finely hirsute, conate, clavate, spinate - which may be densely arranged or scatterd. Low parasutural features may be present on the epicyst.
Archaeopyle: Types (4AI)@ or (5A)@, principal archaeopyle suture zigzag, accessory archaeopyle sutures rarely absent. Operculum typically small relative to cyst diameter, OW/CD ratio less than 0.5, usually between 0.4 and 0.4.
Paratabulation: Expressed mainly by archaeopyle suture, rarely and additionally by generally incomplete parasutural features on opercula; formula for epicyst: 0-2pr?, 4`, 1a, 6`` or, 0-2 pr?, 5`, 6``; paratabulation for hypocyst not known.
Paracingulum: Not indicated or expressed occasionally by vague alignment of ornamentation features in the equatorial area.
Parasulcus: Not indicared.
Size: Small to intermediate, about 40 - 70 µm in diameter.
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Emended diagnosis Wood et al., 2016:
Emended diagnosis: Acavate, subspheroidal to ovoidal, nontabulate, proximate–proximochorate cysts, psilate or bearing ornamentation of low to moderate relief. The archaeopyle is apical or combination, type (5A)@ or type (4A1I)@, with an attached operculum.
Emended description: Proximate to proximochorate acavate dinoflagellate cysts with a subspheroidal to ovoidal central body. The autophragm may either be psilate or bear nontabular elements of low to moderate relief. The archaeopyle involves the four standard gonyaulacalean apical plates plus an additional single dorsal plate that may ormay not reach the apex. Thus the archaeopyle can be interpreted as type (5A)@ or type (4A1I)@; the operculumis attached ventrally,with deep accessory archaeopyle sutures between the six precingular plates typically present. The archaeopyle and operculumare relatively narrow; the overall operculum width/cyst diameter (OW/CD) is b0.5 and normally between 0.4 and 0.3.
Comments: The principal characteristics of Kallosphaeridiumare the small, ventrally attached operculum and the five-plate archaeopyle with associated accessory archaeopyle sutures. In well-preserved specimens, the middorsal 1a/3′ plate should be readily observable from the outline of the operculum. The operculum tends to be narrow relative to the overall cyst diameter. Kallosphaeridium is largely speciated on the nature of its ornamentation, the most variable featurewithin the genus. In terms of the standard gonyaulacalean tabulation, the five plates involved in the archaeopyle include the four standard apicals, homologues 1′ to 4′, plus a smaller dorsal plate, inserted partially or perhaps sometimes wholly between the second and third apical homologues. The additional plate may be a homologue of one of the small dorsal anterior intercalary plates (so-called K plates of Evitt, 1985; see also Fensome et al., 1993, figs. 84–85) of some gonyaulacaceans.
The emendation by Jan du Chêne et al. (1985, p. 8–9) provided more details than were given by de Coninck (1969), especially with regard to the archaeopyle and tabulation. Jan du Chêne et al. (1985, fig. 2.) discussed the overall operculum width/cyst diameter (OW/CD) in Kallosphaeridium. Cysts in this genus consistently have a relatively small archaeopyle and operculum; Jan du Chêne et al. (1985) noted that the OW/CD ratio is b0.5, and typically between 0.4 and 0.3.
Twenty-one species of Kallosphaeridiumwere listed by Fensome and Williams (2004, p. 375–377). Of these, we consider six to be accepted species and six to be provisional; these are included belowin the species lists as well as in Table 2. All six unequivocal species of Kallosphaeridium are of Palaeogene age and fromthe North Atlantic region. Of the six provisional species, the type material of Kallosphaeridium? orchiesense is also Palaeogene (Eocene), while the other five questionable species were described from the Mesozoic of Australia and Europe (Table 2). Fensome et al. (1993) assigned Kallosphaeridiumquestionably to the subfamily Cribroperidinioideae, but for reasons discussed under Phylogenetic affinities below, we prefer to leave its subfamilial affinity as uncertain.
Comparison: Kallosphaeridium is characterised by its relatively small operculum, attached ventrally, and the five-plate archaeopyle consistently with accessory archaeopyle sutures. The archaeopyle was interpreted to be apical (5A)@, or a combination apical (4A1I)@ by Jan du Chêne et al. (1985). The evidence for the five plate archaeopyle is the marked angulation in the middorsal area (Jan du Chêne et al., 1985, fig. 1A–B). The additional dorsal plate was interpreted as either the 1a or the 3′ plate by these authors. No other genus in the Sentusidinium complex has a five plate archaeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Kallosphaeridium de Coninck, 1969, emend. Jan du Chêne et al., 1985a, was emended by Jan du Chêne et al. (1985a, p.8) as follows, cysts proximate, subspherical, without processes, septa or prominent ridges; body composed of endophragm and periphragm or undifferentiated autophragm; body variously ornamented with features of low to moderate relief, ornamentation the same or of two different types on individual specimens; archeopyle type [4AI]@ or [5A]@, operculum typically small relative to cyst diameter, OW/CD ratio 0.5 or less; paratabulation indicated generally by principal and accessory archeopyle sutures only, additionally and rarely by low parasutural features; formula for epicyst 0-2pr?, 4`, 1a, 6", or 0-2pr?, 5`, 6", hypocystal paratabulation not indicated.