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Valensiella pygmaeus
From Fensome et al., 2019:
Valensiella pygmaea (Stevens, 1987, p.186,188, figs.4L–Q) Lentin and Williams, 1993, p.662.
Holotype: Stevens, 1987, figs.4L–N; Fensome et al., 1996, figs.1–3 — p.2309.
NOW Cassiculosphaeridia. Originally (and now) Cassiculosphaeridia, subsequently Valensiella. NIA.
Age: early Berriasian.
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Original description: Stevens, 1987, p. 186: Cassiculosphaeridia pygmaea
Cysts proximate and roundly ellipsoidal in shape. Autophragm 1-1.5 µm thick, ornamented by a low coarse, irregular reticulum, consisting of 1-1.5 µm high and up to 1 µm wide, smooth muri; muri discontinuous in places, delineating subpolygonal to irregularly shaped lumina, 1(1.5)3 Ám in diameter; autophragm scabrate within lumina. Archeopyle apical, type [tA], with zigzag principal suture with short accessory sutures, and a sulcal notch. Operculum rounded and small, adherent or free. Paratabulation indicated by the archeopyle and operculum only; 4 apical and ?5 or ?6 precingular paraplates interpreted. Paracingulum and parasulcus not indicated, however, the anterior end of the parasulcus inferred from the position of the sulcal notch (Fig.4M).
Measurements. Cyst length (dehisced) 31(36)48 µm, cyst width 28(34)39 µm (26 specimens).
Variability: The roundly ellipsoidal shape and small size are consistent features. The reticulum is irregular due to the commonly discontinuous muri which vary little in width and height, but which delineate irregular to subpolygonal lumina of varying sizes. The operculum is adherent or free and is less than half as wide as the cyst. The archeopyle is commonly distorted and enlarged due to compression of the cyst; it is generally one half to two thirds as wide as the cyst. The number of precingular paraplates is unclear, being interpreted as 5 on the holotype (Fig.4L-N) and 6 on one paratype (Fig.4Q).
Affinities:
Stvens, 1987, p. 186: Cassiculosphaeridia pygmaea
This species is similar to species of Palaeostomocystis Deflandre 1937 in being ellipsoidal and reticulate, however it has a zigzag, rather than a rounded, principal archeopyle suture. The species is placed in Cassiculosphaeridia on the basis of its zigzag archeopyle, although it is roundly ellipsoidal and not subspherical in shape. The ratio of operculum width to cyst width (1:2) in C. pygmaea is generally the same as that for C. reticulata Davey 1969, C. magna Davey 1974 and C. delicata Stover & Helby (this memoir a). However, the last 3 species differ from C. pygmaea in being subspherical in shape and larger in size. Also C. magna has broad muri and circular lumina and C. delicata is tabulate.
Valensiella pygmaea (Stevens, 1987, p.186,188, figs.4L–Q) Lentin and Williams, 1993, p.662.
Holotype: Stevens, 1987, figs.4L–N; Fensome et al., 1996, figs.1–3 — p.2309.
NOW Cassiculosphaeridia. Originally (and now) Cassiculosphaeridia, subsequently Valensiella. NIA.
Age: early Berriasian.
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Original description: Stevens, 1987, p. 186: Cassiculosphaeridia pygmaea
Cysts proximate and roundly ellipsoidal in shape. Autophragm 1-1.5 µm thick, ornamented by a low coarse, irregular reticulum, consisting of 1-1.5 µm high and up to 1 µm wide, smooth muri; muri discontinuous in places, delineating subpolygonal to irregularly shaped lumina, 1(1.5)3 Ám in diameter; autophragm scabrate within lumina. Archeopyle apical, type [tA], with zigzag principal suture with short accessory sutures, and a sulcal notch. Operculum rounded and small, adherent or free. Paratabulation indicated by the archeopyle and operculum only; 4 apical and ?5 or ?6 precingular paraplates interpreted. Paracingulum and parasulcus not indicated, however, the anterior end of the parasulcus inferred from the position of the sulcal notch (Fig.4M).
Measurements. Cyst length (dehisced) 31(36)48 µm, cyst width 28(34)39 µm (26 specimens).
Variability: The roundly ellipsoidal shape and small size are consistent features. The reticulum is irregular due to the commonly discontinuous muri which vary little in width and height, but which delineate irregular to subpolygonal lumina of varying sizes. The operculum is adherent or free and is less than half as wide as the cyst. The archeopyle is commonly distorted and enlarged due to compression of the cyst; it is generally one half to two thirds as wide as the cyst. The number of precingular paraplates is unclear, being interpreted as 5 on the holotype (Fig.4L-N) and 6 on one paratype (Fig.4Q).
Affinities:
Stvens, 1987, p. 186: Cassiculosphaeridia pygmaea
This species is similar to species of Palaeostomocystis Deflandre 1937 in being ellipsoidal and reticulate, however it has a zigzag, rather than a rounded, principal archeopyle suture. The species is placed in Cassiculosphaeridia on the basis of its zigzag archeopyle, although it is roundly ellipsoidal and not subspherical in shape. The ratio of operculum width to cyst width (1:2) in C. pygmaea is generally the same as that for C. reticulata Davey 1969, C. magna Davey 1974 and C. delicata Stover & Helby (this memoir a). However, the last 3 species differ from C. pygmaea in being subspherical in shape and larger in size. Also C. magna has broad muri and circular lumina and C. delicata is tabulate.