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Endoscrinium galeritum ssp. reticulatum
From Fensome et al., 2019:
Endoscrinium galeritum ssp. reticulatum (Klement, 1960, p.26–27, pl.2, figs.1–2) Górka, 1970, p.491. Holotype: Klement, 1960, pl.2, figs.1–2; Eisenack and Klement, 1964, p.765; Jan du Chêne et al., 1986a, pl.108, figs.9–10; Fensome et al., 1995, figs.1–2 — p.1739; disintegrated according to Sarjeant (1984a, p.155). Originally Scriniodinium galeritum subsp. reticulatum, subsequently (and now) Endoscrinium galeritum subsp. reticulatum. Lentin and Williams (1973, p.54) also proposed this combination. Jan du Chêne et al. (1986a, p.316–317) and Riding and Fensome (2002, p.23) considered Scriniodinium (now Endoscrinium) subvallare to be a possible taxonomic synonym of this taxon. Age: middle Oxfordian.
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Original description (Klement, 1960) (translated from German):
Scriniodinium galeritum reticulatum n. subsp.
Plate 2, Figs. 1, 2
Derivation nominis: Reference to the reticulated external membrane.
Diagnosis: A subspecies of Scriniodinium (Endoscr.) galeritum (DEFL.) with the distinctive feature of an external membrane divided into irregular, polygonal meshwork. The general habitus is characterized by the bulbous protrusion of the external membrane in the apical, antapical, and marginal directions.
Description: This subspecies was also found less frequently, but is immediately noticeable due to the irregular, polygonal meshwork of the external membrane. The majority of the specimens were in ideal physical condition, with no signs of damage to the meshwork, which indicates a fairly stable network. The mesh size varies; It ranges between 2.5 and 6 u.
Due to the membranous structure, the plaiting usually appears very indistinct; especially on the ventral side, it is sometimes indefinable. The tabulation scheme could therefore only be determined by comparing several favorable specimens. The third preequatorial plate, in turn, forms the hatch.
The girdle furrow has a spiral course; its ends are offset by up to 2.5 furrow widths. The depression is small. The longitudinal furrow can usually only be recognized by the groove-like indentation.
The external outline is determined by the strong, bulbous protrusions of the outer shell toward the apex and antapex, as well as on both sides of the girdle furrow. The inner body, in turn, appears considerably darker than the outer shell and is deep brown in color.
The form of destruction of the antapex described in the previous subspecies has not yet been observed in this type.
Remarks: No actual transitional forms were found in the formation of the polygonal reticular structure of the external membrane. However, a species separation was not carried out due to the otherwise completely consistent overall body plan. This differentiation may even be merely a special state of preservation of the outer shell.
Relationships: Differentiation from the other subspecies of Scr. (Endoscr.) galeritum is easily achieved by the criterion of the special formation of the external membrane. The species Palaeoperidinium dictyophorum, described by Deflandre (1938), probably displays an analogous membrane structure, but exhibits considerable morphological differences with regard to its polyhedral shape.
Dimensions: External shell Inner body
Holotype: 84 : 66 58 : 55
Paratypoids: 75 : 66 58 : 52
78 : 66 58 : 55
Number of specimens examined: Approximately 20.
Endoscrinium galeritum ssp. reticulatum (Klement, 1960, p.26–27, pl.2, figs.1–2) Górka, 1970, p.491. Holotype: Klement, 1960, pl.2, figs.1–2; Eisenack and Klement, 1964, p.765; Jan du Chêne et al., 1986a, pl.108, figs.9–10; Fensome et al., 1995, figs.1–2 — p.1739; disintegrated according to Sarjeant (1984a, p.155). Originally Scriniodinium galeritum subsp. reticulatum, subsequently (and now) Endoscrinium galeritum subsp. reticulatum. Lentin and Williams (1973, p.54) also proposed this combination. Jan du Chêne et al. (1986a, p.316–317) and Riding and Fensome (2002, p.23) considered Scriniodinium (now Endoscrinium) subvallare to be a possible taxonomic synonym of this taxon. Age: middle Oxfordian.
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Original description (Klement, 1960) (translated from German):
Scriniodinium galeritum reticulatum n. subsp.
Plate 2, Figs. 1, 2
Derivation nominis: Reference to the reticulated external membrane.
Diagnosis: A subspecies of Scriniodinium (Endoscr.) galeritum (DEFL.) with the distinctive feature of an external membrane divided into irregular, polygonal meshwork. The general habitus is characterized by the bulbous protrusion of the external membrane in the apical, antapical, and marginal directions.
Description: This subspecies was also found less frequently, but is immediately noticeable due to the irregular, polygonal meshwork of the external membrane. The majority of the specimens were in ideal physical condition, with no signs of damage to the meshwork, which indicates a fairly stable network. The mesh size varies; It ranges between 2.5 and 6 u.
Due to the membranous structure, the plaiting usually appears very indistinct; especially on the ventral side, it is sometimes indefinable. The tabulation scheme could therefore only be determined by comparing several favorable specimens. The third preequatorial plate, in turn, forms the hatch.
The girdle furrow has a spiral course; its ends are offset by up to 2.5 furrow widths. The depression is small. The longitudinal furrow can usually only be recognized by the groove-like indentation.
The external outline is determined by the strong, bulbous protrusions of the outer shell toward the apex and antapex, as well as on both sides of the girdle furrow. The inner body, in turn, appears considerably darker than the outer shell and is deep brown in color.
The form of destruction of the antapex described in the previous subspecies has not yet been observed in this type.
Remarks: No actual transitional forms were found in the formation of the polygonal reticular structure of the external membrane. However, a species separation was not carried out due to the otherwise completely consistent overall body plan. This differentiation may even be merely a special state of preservation of the outer shell.
Relationships: Differentiation from the other subspecies of Scr. (Endoscr.) galeritum is easily achieved by the criterion of the special formation of the external membrane. The species Palaeoperidinium dictyophorum, described by Deflandre (1938), probably displays an analogous membrane structure, but exhibits considerable morphological differences with regard to its polyhedral shape.
Dimensions: External shell Inner body
Holotype: 84 : 66 58 : 55
Paratypoids: 75 : 66 58 : 52
78 : 66 58 : 55
Number of specimens examined: Approximately 20.