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Wetzeliella articulata
Wetzeliella articulata Eisenack, 1938
Originally (and now) Wetzeliella, subsequently Palaeoperidinium (name not validly published), thirdly Hystrichosphaeridium, fourthly Wetzeliella subgenus Wetzeliella.
Taxonomic junior synonym: Wetzeliella echinulata, according to Costa and Downie (1979, p.40);
Taxonomic junior synonym: Wetzeliella horrida, according to Stover and Evitt (1978, p.131);
Taxonomic junior synonym: Rhombodinium (as Wetzeliella) coronatum, according to Costa and Downie (1979, p.43) — however, Iakovleva and Heilmann-Clausen (2010, p. 211,226) retained Rhombodinium (as Wetzeliella) coronatum;
Taxonomic junior synonym: Rhombodinium pentagonum, according to Costa and Downie (1979, p.40) — however, Lentin and Williams (1981, p.244) retained Rhombodinium pentagonum;
Taxonomic junior synonym: Wetzeliella hampdenensis, according to Costa and Downie (1979, p.40) — however, Lentin and Williams (1981, p.290) retained Wetzeliella hampdenensis;
Taxonomic junior synonym: Wetzeliella (now Charlesdowniea) clathrata, according to Pastiels (1948, p.42) — however, this synonymy has not been generally accepted.
Holotype: Eisenack, 1938, fig.4 and Eisenack, 1954, pl.7, fig.3 (non pl.7, fig.1 as indicated in Eisenack, 1954, caption to pl.7, fig.1-p.90
Locus typicus: Palmnicken, Samland, E Prussia, Russia
Stratum typicum: Late Eocene-Early Oligocene
Translations Eisenack, 1938 and 1954: LPP
Translation Gocht, 1969: Geological Survey of Canada
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Wetzeliella articulata Eisenack, 1938b. Diagnosis, according to Eisenack (1954b), pericyst flattended, rhomboidal outline, with one apical, two lateral and two antapical horns of unequal size, through which the W.articulata outline takes on a characteristic peridinian like pentagonal shape. Armour shows no tabulation and appears to be thick and transparent. Transverse furrow indicated at times, longitudinal furrow not developed. Especially at its lateral boundaries, the armour is equipped with thick spines. In its interior portion, a circular to ellipsoidal, likewise flattened capsule is visible, which generally does not come into direct contact with the external boundary. Eisenack (1954b) in commenting on the escape hole noted that this was only rarely seen (possibly because the operculum remains attached). In one specimen he noted that the cover is still attached along the anterior margin of the archeopyle. The archeopyle was somewhat quadrate. In another specimen, the archeopyle was more elongate. He noted that archeopyles occur in partially opened-up state or partially with the cover still in place. In contrast to other species (such as W.ovalis, W.samlandica and W.similis), the opening mechanism of the slip hole is here somewhat changed. To be sure, the cover separates along a circular seam from the remaining shell (at times said seam is quadratic with rounded-off corners), however, it remains connected to the remaining shell portion with its upper marginal region, that is to say closely below the apex and flaps upwardly in similar manner as a tongue. This cover can certainly separate itself completely from the shell. In one case the cover of the capsule seems to lie in the capsule’s cavity, while the external armour only shows the delineating tear or the seam. Based on the holotype, Wetzeliella articulata should have a soleiform archeopyle. Size: holotype, 167:156 µm, capsule 100:100 µm, length fluctuates between 114-196 µm, width between 105-178 µm. Generally the length breadth ratio is slightly above 1.
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Eisenack, 1938, p. 186-187
(annotated) Amongst the dinoflagellates, which form a remarkable portion of the small forms of the phosphorites, two groups are discerned: In the first we encounter forms, which do not essentially differ from the Recent species and which are easily classified in the known genera; in the other group there are species, which apparently belong in the tertiary , and which have not yet been encountered in the Cretaceous. They are principally three species with firm membranes: Wetzeliella articulata (O. Wetzel), Wetzeliella clathrata and Deflandrea phosphoritica. O. Wetzel initially classified the first species as Palaeoperidinium articulatum. Wetzeliella clathrata differs from it in the more diamond-shaped outline and the balustrade-like fusion of the marginal spines. Nevertheless, in my opinion these two species are not related to Palaeoperidinium because of the absence of tabulation or signs thereof, and because of the character of the furrows. Therefore I would suggest the name Wetzeliella to accommodate both species.
Original description: Eisenack 1954, p. 55
Diagnosis: Central body is flattened, the shape in outline is rhomboidal, with an apical horn, two lateral horns, and two mainly unequal antapical horns, which gives the total outline a characteristic peridinioid-like pentagonal shape. The shell is untabulated, thick, and transparant. The transverse furrow is sometimes indicated (?), the longitudinal furrow is not developed. The shell, especially the sharp margins, is provided with short, strong thorns (or brushes). Inside, a circular to ellipsoidal, similarly flattened inner capsule is present, which does not touch the outer wall.
Description (annotated): W.articulata varies heavily. The apical horn is nearly always distinct, the lateral horns extend unequally far, which affects the length-width. Generally also the antapical horns are clearly developed and unequal in size; the difference between them can be obscure, but also extensive. The apical and antapical horns are always sharp; the lateral horns are rounded or indented, which is often expressed by the diverging marginal spines. The shell in untabulated, transparent, brownish, yellowish to almost colourless. The (more or less closely spaced) ornamentation of brushes does not show a distinct arrangement. The ends of the brushes are often slightly furcate.
In the type-specimen dorsally, where the transversal furrow is to be expected, a crack 'yawns' from the right lateral horn up to almost the left horn; the bordering thorns at the margins of the crack are slightly curved, which produces a more distinct line. The ovoidal to circular inner capsule leaves between itself and the outer wall of the shell a more or less broad belt. Between shell and capsule a cavity is present; the apical horn, lateral horns, and antapical horns are cavate. Only at the dorsal and ventral sides both bodies touch each other.
Dimensions: Length: 114-196 µm; width: 105-178 µm; Generally the length/width ratio is slightly larger than 1.
Gocht, 1969, p.13:
Only very few specimens represented this species, which was common in the Eocene. Three are well preserved and characteristic. Among the Wetzeliella specimens of uncertain identification, there are also some which could be classed in the vicinity of W. articulata, but could also fall within the range of variation of other species. These specimens are mostly very fragile.
The archeopyle, which is not very large, is rounded-trapezoidal to oval. The archeopyle margins of capsule and outer membrane are congruent, as could be observed also on specimens from the Eocene of Heiligenhafen (material of Agelopoulos). One of the typical individuals exhibits a splendid flagellar inesertion.
Material: 4 specimens.
Occurrence: ?Late Eocene- Middle Oligocene.
Originally (and now) Wetzeliella, subsequently Palaeoperidinium (name not validly published), thirdly Hystrichosphaeridium, fourthly Wetzeliella subgenus Wetzeliella.
Taxonomic junior synonym: Wetzeliella echinulata, according to Costa and Downie (1979, p.40);
Taxonomic junior synonym: Wetzeliella horrida, according to Stover and Evitt (1978, p.131);
Taxonomic junior synonym: Rhombodinium (as Wetzeliella) coronatum, according to Costa and Downie (1979, p.43) — however, Iakovleva and Heilmann-Clausen (2010, p. 211,226) retained Rhombodinium (as Wetzeliella) coronatum;
Taxonomic junior synonym: Rhombodinium pentagonum, according to Costa and Downie (1979, p.40) — however, Lentin and Williams (1981, p.244) retained Rhombodinium pentagonum;
Taxonomic junior synonym: Wetzeliella hampdenensis, according to Costa and Downie (1979, p.40) — however, Lentin and Williams (1981, p.290) retained Wetzeliella hampdenensis;
Taxonomic junior synonym: Wetzeliella (now Charlesdowniea) clathrata, according to Pastiels (1948, p.42) — however, this synonymy has not been generally accepted.
Holotype: Eisenack, 1938, fig.4 and Eisenack, 1954, pl.7, fig.3 (non pl.7, fig.1 as indicated in Eisenack, 1954, caption to pl.7, fig.1-p.90
Locus typicus: Palmnicken, Samland, E Prussia, Russia
Stratum typicum: Late Eocene-Early Oligocene
Translations Eisenack, 1938 and 1954: LPP
Translation Gocht, 1969: Geological Survey of Canada
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Wetzeliella articulata Eisenack, 1938b. Diagnosis, according to Eisenack (1954b), pericyst flattended, rhomboidal outline, with one apical, two lateral and two antapical horns of unequal size, through which the W.articulata outline takes on a characteristic peridinian like pentagonal shape. Armour shows no tabulation and appears to be thick and transparent. Transverse furrow indicated at times, longitudinal furrow not developed. Especially at its lateral boundaries, the armour is equipped with thick spines. In its interior portion, a circular to ellipsoidal, likewise flattened capsule is visible, which generally does not come into direct contact with the external boundary. Eisenack (1954b) in commenting on the escape hole noted that this was only rarely seen (possibly because the operculum remains attached). In one specimen he noted that the cover is still attached along the anterior margin of the archeopyle. The archeopyle was somewhat quadrate. In another specimen, the archeopyle was more elongate. He noted that archeopyles occur in partially opened-up state or partially with the cover still in place. In contrast to other species (such as W.ovalis, W.samlandica and W.similis), the opening mechanism of the slip hole is here somewhat changed. To be sure, the cover separates along a circular seam from the remaining shell (at times said seam is quadratic with rounded-off corners), however, it remains connected to the remaining shell portion with its upper marginal region, that is to say closely below the apex and flaps upwardly in similar manner as a tongue. This cover can certainly separate itself completely from the shell. In one case the cover of the capsule seems to lie in the capsule’s cavity, while the external armour only shows the delineating tear or the seam. Based on the holotype, Wetzeliella articulata should have a soleiform archeopyle. Size: holotype, 167:156 µm, capsule 100:100 µm, length fluctuates between 114-196 µm, width between 105-178 µm. Generally the length breadth ratio is slightly above 1.
--------------------------------------------------
Eisenack, 1938, p. 186-187
(annotated) Amongst the dinoflagellates, which form a remarkable portion of the small forms of the phosphorites, two groups are discerned: In the first we encounter forms, which do not essentially differ from the Recent species and which are easily classified in the known genera; in the other group there are species, which apparently belong in the tertiary , and which have not yet been encountered in the Cretaceous. They are principally three species with firm membranes: Wetzeliella articulata (O. Wetzel), Wetzeliella clathrata and Deflandrea phosphoritica. O. Wetzel initially classified the first species as Palaeoperidinium articulatum. Wetzeliella clathrata differs from it in the more diamond-shaped outline and the balustrade-like fusion of the marginal spines. Nevertheless, in my opinion these two species are not related to Palaeoperidinium because of the absence of tabulation or signs thereof, and because of the character of the furrows. Therefore I would suggest the name Wetzeliella to accommodate both species.
Original description: Eisenack 1954, p. 55
Diagnosis: Central body is flattened, the shape in outline is rhomboidal, with an apical horn, two lateral horns, and two mainly unequal antapical horns, which gives the total outline a characteristic peridinioid-like pentagonal shape. The shell is untabulated, thick, and transparant. The transverse furrow is sometimes indicated (?), the longitudinal furrow is not developed. The shell, especially the sharp margins, is provided with short, strong thorns (or brushes). Inside, a circular to ellipsoidal, similarly flattened inner capsule is present, which does not touch the outer wall.
Description (annotated): W.articulata varies heavily. The apical horn is nearly always distinct, the lateral horns extend unequally far, which affects the length-width. Generally also the antapical horns are clearly developed and unequal in size; the difference between them can be obscure, but also extensive. The apical and antapical horns are always sharp; the lateral horns are rounded or indented, which is often expressed by the diverging marginal spines. The shell in untabulated, transparent, brownish, yellowish to almost colourless. The (more or less closely spaced) ornamentation of brushes does not show a distinct arrangement. The ends of the brushes are often slightly furcate.
In the type-specimen dorsally, where the transversal furrow is to be expected, a crack 'yawns' from the right lateral horn up to almost the left horn; the bordering thorns at the margins of the crack are slightly curved, which produces a more distinct line. The ovoidal to circular inner capsule leaves between itself and the outer wall of the shell a more or less broad belt. Between shell and capsule a cavity is present; the apical horn, lateral horns, and antapical horns are cavate. Only at the dorsal and ventral sides both bodies touch each other.
Dimensions: Length: 114-196 µm; width: 105-178 µm; Generally the length/width ratio is slightly larger than 1.
Gocht, 1969, p.13:
Only very few specimens represented this species, which was common in the Eocene. Three are well preserved and characteristic. Among the Wetzeliella specimens of uncertain identification, there are also some which could be classed in the vicinity of W. articulata, but could also fall within the range of variation of other species. These specimens are mostly very fragile.
The archeopyle, which is not very large, is rounded-trapezoidal to oval. The archeopyle margins of capsule and outer membrane are congruent, as could be observed also on specimens from the Eocene of Heiligenhafen (material of Agelopoulos). One of the typical individuals exhibits a splendid flagellar inesertion.
Material: 4 specimens.
Occurrence: ?Late Eocene- Middle Oligocene.