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Dapsilidinium daveyi
From Fensome et al., 2019:
Dapsilidinium daveyi (Boltenhagen, 1977, p.37–38,40, pl.2, figs.3–4) Lentin and Williams, 1981, p.69. Holotype: Boltenhagen, 1977, pl.2, fig.3; Fauconnier and Masure, 2004, pl.20, fig.3. Originally Polysphaeridium?, subsequently (and now) Dapsilidinium. Age: late Cenomanian–Turonian.
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Original description: [Boltenhagen, 1977] (translated from French):
?Polypshaeridium daveyi nov. sp.
Sibang Series, Turonian; Libreville (Gabon, South Africa).
DAGNOSIS
Subspherical or ovoid shell, with numerous tubular appendages of approximately equal size and various shapes, some of which have fused bases. Apical archaeopyle.
DESCRIPTION
The subspherical or ovoid shell of our specimens is formed by a two-layer membrane. The endophragm, approximately one micron thick, is covered by microgranules only visible at 800x magnification. The smooth periphragm covers these microwarts, so that at 320x magnification, the shell appears weakly punctuated. Numerous appendages (about 40), tubular but fairly rigid, of approximately the same length, are distributed evenly throughout the shell. The ends of these appendages have various pointed, bifid, or flared shapes. Furthermore, some of these appendages have broad common bases and only separate halfway up; a few others, on the contrary, are independent at the base but merge towards the middle and branch off again at the top.
The periphragm is detached at the appendages, showing that they are not in communication with the interior of the shell. A large archaeopyle, seen in profile, shows its zigzagging edges and would correspond to the apical region.
OBSERVATIONS
Whole specimens of this species are very rare. Most often, only torn specimens or their fragments are observed.
DIMENSIONS
Holotype: shell (with appendages): d' = 70 x 67 μ
shell (without appendages): d'' = 48 x 46 μ
appendages l = 11, 12, 14 μ
Paratypes: shell (with appendages): d' = 57 x 56 μ
shell (without appendages): d'' = 39 x 34 μ
appendages l = 11, 12, 13 μ
Based on 3 other specimens:
shell (with appendages): d' = 68 x 54 μ; 67 x 61 μ; 65 x 58 μ
shell (without appendages): d'' = 52 x 40 μ; 50 x 46 μ; 46 x 40 μ
appendages l = 11, 12, 13, 14 μ
COMPARISON
The specimens described have many similarities with P. subtile DAV. and WIL. 1966 (p. 92, Pl. 11, Fig. I) and are essentially distinguished only by the presence of paired appendages. This does not contradict the diagnosis of the genus (pp. 91, 92). However, in general, the species described by R.J. DAVEY and G.L. WILLIAMS (1966) have individual appendages, which leaves some doubt as to the belonging of these species to the genus Polysphaeridium. Hystrichosphaeridium zoharyi ROSS. 1964 (p. 88, Pl. 2, Fig. 4, 9, 11, 4 bis and PI. 3, Fig. 10) also resembles our form, which differs, however, in its appendages of various shapes.
Stratigraphic and Geographic Position
Upper Cretaceous: Upper Cenomanian - Turonian; Gabon (Libreville).
Dapsilidinium daveyi (Boltenhagen, 1977, p.37–38,40, pl.2, figs.3–4) Lentin and Williams, 1981, p.69. Holotype: Boltenhagen, 1977, pl.2, fig.3; Fauconnier and Masure, 2004, pl.20, fig.3. Originally Polysphaeridium?, subsequently (and now) Dapsilidinium. Age: late Cenomanian–Turonian.
---------------------------------------------------------------------------------------------------
Original description: [Boltenhagen, 1977] (translated from French):
?Polypshaeridium daveyi nov. sp.
Sibang Series, Turonian; Libreville (Gabon, South Africa).
DAGNOSIS
Subspherical or ovoid shell, with numerous tubular appendages of approximately equal size and various shapes, some of which have fused bases. Apical archaeopyle.
DESCRIPTION
The subspherical or ovoid shell of our specimens is formed by a two-layer membrane. The endophragm, approximately one micron thick, is covered by microgranules only visible at 800x magnification. The smooth periphragm covers these microwarts, so that at 320x magnification, the shell appears weakly punctuated. Numerous appendages (about 40), tubular but fairly rigid, of approximately the same length, are distributed evenly throughout the shell. The ends of these appendages have various pointed, bifid, or flared shapes. Furthermore, some of these appendages have broad common bases and only separate halfway up; a few others, on the contrary, are independent at the base but merge towards the middle and branch off again at the top.
The periphragm is detached at the appendages, showing that they are not in communication with the interior of the shell. A large archaeopyle, seen in profile, shows its zigzagging edges and would correspond to the apical region.
OBSERVATIONS
Whole specimens of this species are very rare. Most often, only torn specimens or their fragments are observed.
DIMENSIONS
Holotype: shell (with appendages): d' = 70 x 67 μ
shell (without appendages): d'' = 48 x 46 μ
appendages l = 11, 12, 14 μ
Paratypes: shell (with appendages): d' = 57 x 56 μ
shell (without appendages): d'' = 39 x 34 μ
appendages l = 11, 12, 13 μ
Based on 3 other specimens:
shell (with appendages): d' = 68 x 54 μ; 67 x 61 μ; 65 x 58 μ
shell (without appendages): d'' = 52 x 40 μ; 50 x 46 μ; 46 x 40 μ
appendages l = 11, 12, 13, 14 μ
COMPARISON
The specimens described have many similarities with P. subtile DAV. and WIL. 1966 (p. 92, Pl. 11, Fig. I) and are essentially distinguished only by the presence of paired appendages. This does not contradict the diagnosis of the genus (pp. 91, 92). However, in general, the species described by R.J. DAVEY and G.L. WILLIAMS (1966) have individual appendages, which leaves some doubt as to the belonging of these species to the genus Polysphaeridium. Hystrichosphaeridium zoharyi ROSS. 1964 (p. 88, Pl. 2, Fig. 4, 9, 11, 4 bis and PI. 3, Fig. 10) also resembles our form, which differs, however, in its appendages of various shapes.
Stratigraphic and Geographic Position
Upper Cretaceous: Upper Cenomanian - Turonian; Gabon (Libreville).