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Pyxidinopsis brabantiana
Pyxidinopsis brabantiana Louwye, 2001, p.129, fig.7, nos.1–11.
Holotype: Louwye, 2001, fig.7, nos.1–3.
Age: early-middle Miocene.
Original description (Louwye, 2001)
Holotype - Slide A.M.54/P1, England Finder reference D41/3 (Fig. 7, 1-3).
Etymology - named after the type locality Antwerp, which is part of the Duchy of Brabant.
Repository - collection of the 'Institut Royal des Sciences Naturelles' (Brussels), catalogue number IRScN b3670.
Type locality - Outcrop 'Antwerp Montignystraat' described by De Meuter et al. (1976: 5), altitude -0.3 m O.D. (Ostend Datum), Antwerp, Antwerp Province, Belgium.
Type stratum - Edegem Sands, Berchem Formation, Lower Miocene.
Diagnosis: Small, ovoid to ellipsoid proximate cyst. The wall consists of a thin pedium densely covered with prismatic luxuriae consisting of closely spaced bacula. The shape of the bacula is rather irregular and the bacula are distally and laterally fused to a certain degree. The archeopyle is formed by the release of precingular plate 3". The operculum is free or adherent.
Description: The thickness of the pedium is less than 0.5 µm. The height of the irregular shaped bacula is uniform on each specimen "and rarely exceeds 2 - 3 µm. The bacula arise directly from the pedium. Since the bacula are densely packed, it is difficult to ascertain, even with a scanning electron microscope, whether proximal fusion also occurs. Under the light microscope, the dense layer of bacula appears in optical section relatively homogeneous, in high focus the surface appears finely granulate. The small, precingular archeopyle (type P) has a trapezoid outline with smooth margins. Apart from the archeopyle there are no indications of tabulation.
Dimensions: Holotype: maximum length: 36 µm, maximum width: 30 µm, wall thickness: 3 µm. Range: maximum length: 36 (39) 44 µm, maximum width: 30 (31.5) 38 µm, wall thickness: 1.8 (2.9) 3.5 µm. Number of specimens measured: 7.
Comparison: Pyxidinopsis pastilliformis Head, 1992 (in Matsuoka & Head 1992) resembles the new species most closely but is distinguished by the larger archeopyle, spherical shape, thin wall (0.4 - 0.8 µm) and the granulate/microvermicutate to microreticulate ornament of the wall. Pyxidinopsis fairhavenensis de Verteuil & Norris, 1996 differs by its coarsely granulate to rugulate wall, ornamented with rounded granules or tapered, low coni. Pyxidinopsis psilata (Wall & Dale, 1973) (in Wall et al. 1973) is a thin-walled species with a psilate, minutely punctate or scabrate wall surface. Habibacysta tectata Head et al. 1989 differs by its characteristic tegillate/columellate wall structure. Pyxidinopsis brabantiana nov. sp. definitely lacks a tegillum. Species attributed to the genus Tectatodinium Wall, 1967 are characterised by the spongy appearance of the luxuria which consists of interconnecting, irregular, perforate lamellae (Head 1994). The new species is similar to Operculodinium placitum Drugg, 1967 in overall shape and archeopyle type. However, the latter species is smaller and has low, solid virgae.
Remarks - Although no description is provided, Pyxidinopsis psilata (as Tectatodinium psilatum) in Manure et al. 1989), pl.20, fig. 1 non fig. 5 may be conspecific with Pyxidinopsis brabantiana nov. sp.Occurrence - Lower to Middle Miocene (Edegem Sands, Kiel Sands, Antwerpen Sands and Zonderschot Sands of the Berchem Formation) of northern Belgium as Pyxidinopsis sp. 1.(Louwye in press, Louwye et al. 2000)
Holotype: Louwye, 2001, fig.7, nos.1–3.
Age: early-middle Miocene.
Original description (Louwye, 2001)
Holotype - Slide A.M.54/P1, England Finder reference D41/3 (Fig. 7, 1-3).
Etymology - named after the type locality Antwerp, which is part of the Duchy of Brabant.
Repository - collection of the 'Institut Royal des Sciences Naturelles' (Brussels), catalogue number IRScN b3670.
Type locality - Outcrop 'Antwerp Montignystraat' described by De Meuter et al. (1976: 5), altitude -0.3 m O.D. (Ostend Datum), Antwerp, Antwerp Province, Belgium.
Type stratum - Edegem Sands, Berchem Formation, Lower Miocene.
Diagnosis: Small, ovoid to ellipsoid proximate cyst. The wall consists of a thin pedium densely covered with prismatic luxuriae consisting of closely spaced bacula. The shape of the bacula is rather irregular and the bacula are distally and laterally fused to a certain degree. The archeopyle is formed by the release of precingular plate 3". The operculum is free or adherent.
Description: The thickness of the pedium is less than 0.5 µm. The height of the irregular shaped bacula is uniform on each specimen "and rarely exceeds 2 - 3 µm. The bacula arise directly from the pedium. Since the bacula are densely packed, it is difficult to ascertain, even with a scanning electron microscope, whether proximal fusion also occurs. Under the light microscope, the dense layer of bacula appears in optical section relatively homogeneous, in high focus the surface appears finely granulate. The small, precingular archeopyle (type P) has a trapezoid outline with smooth margins. Apart from the archeopyle there are no indications of tabulation.
Dimensions: Holotype: maximum length: 36 µm, maximum width: 30 µm, wall thickness: 3 µm. Range: maximum length: 36 (39) 44 µm, maximum width: 30 (31.5) 38 µm, wall thickness: 1.8 (2.9) 3.5 µm. Number of specimens measured: 7.
Comparison: Pyxidinopsis pastilliformis Head, 1992 (in Matsuoka & Head 1992) resembles the new species most closely but is distinguished by the larger archeopyle, spherical shape, thin wall (0.4 - 0.8 µm) and the granulate/microvermicutate to microreticulate ornament of the wall. Pyxidinopsis fairhavenensis de Verteuil & Norris, 1996 differs by its coarsely granulate to rugulate wall, ornamented with rounded granules or tapered, low coni. Pyxidinopsis psilata (Wall & Dale, 1973) (in Wall et al. 1973) is a thin-walled species with a psilate, minutely punctate or scabrate wall surface. Habibacysta tectata Head et al. 1989 differs by its characteristic tegillate/columellate wall structure. Pyxidinopsis brabantiana nov. sp. definitely lacks a tegillum. Species attributed to the genus Tectatodinium Wall, 1967 are characterised by the spongy appearance of the luxuria which consists of interconnecting, irregular, perforate lamellae (Head 1994). The new species is similar to Operculodinium placitum Drugg, 1967 in overall shape and archeopyle type. However, the latter species is smaller and has low, solid virgae.
Remarks - Although no description is provided, Pyxidinopsis psilata (as Tectatodinium psilatum) in Manure et al. 1989), pl.20, fig. 1 non fig. 5 may be conspecific with Pyxidinopsis brabantiana nov. sp.Occurrence - Lower to Middle Miocene (Edegem Sands, Kiel Sands, Antwerpen Sands and Zonderschot Sands of the Berchem Formation) of northern Belgium as Pyxidinopsis sp. 1.(Louwye in press, Louwye et al. 2000)