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Lejeunecysta tenella
Lejeunecysta tenella (Morgenroth, 1966) Wilson and Clowes, 1980
Originally Lejeunia (an illegitimate generic name), subsequently Vozzhennikovia, thirdly Dioxya, fourthly (and now) Lejeunecysta.
Lentin and Williams, 1976, transferred this species to Vozzhennikovia Lentin and Williams, 1976. Stover and Evitt, 1978, retained it in Lejeunia Gerlach, 1961 (an illegitimate generic name).
Lentin and Williams, 1981, also effected the transfer of this species to Lejeunecysta.
Holotype: Morgenroth 1966, pl.1, fig.8
Age: Early Oligocene
Original Description Lejeunia tenella Morgenroth, 1966
Derivatio nominis: tenellus Latin = delicate.
Holotype: The in Slide H18 preserved and shown on plate 1, fig. 8. Paratypoids: H18/II, HS, Io3 4, Io38.
Locus typicus: Depold'sche Ziegelei (south of Helmstedt).
Stratum typicum: Lower Oligocene
Diagnosis: A species of the genus Lejeunia with a broad, circular girdle furrow, which is bordered by margins of teeth. The smooth, delicate theca is loosely decorated with thorns, which can be arranged in rows.
Description: The delicate, smooth theca has a bilaterally symmetrical pentagonal outline. It is loosely covered with small thorns, which can also be arranged in rows. The circular, fairly wide girdle furrow is slightly depressed. It is bordered on both sides by a border of tiny teeth. A longitudinal furrow is indicated by its ventral interruption. The arch ends in a clearly pointed horn - in one specimen it extends like a tip. The two antapical horns are also very much advanced and pointed.
Dimensions:
Cyst length: 63µ (45µ–84µ)
Cyst width: 52µ (33µ–61µ)
(5 specimens measured)
Comparison: So far, no species of the genus Lejeunia is known whose capsule is covered with thorns.
Remarks: In contrast to the genotype of the genus Ginginodinium COOKSON & EISENACK 1960, the horns are not closed off from the interior. Although the genus diagnosis of Ginginodinium expressly mentions the absence of an inner capsule, EISENACK 1961 mentions that in one specimen "the shell consisted of 2 cases that were clearly distinguishable in places" and that in all specimens the hollow horns were closed off from the interior. The latter finding also points to a delicate inner capsule, albeit one that is very difficult to observe. If this is actually present, then the “genotype” would be a Deflandrea species, so that the genus Ginginodinium would have to be deleted.
Originally Lejeunia (an illegitimate generic name), subsequently Vozzhennikovia, thirdly Dioxya, fourthly (and now) Lejeunecysta.
Lentin and Williams, 1976, transferred this species to Vozzhennikovia Lentin and Williams, 1976. Stover and Evitt, 1978, retained it in Lejeunia Gerlach, 1961 (an illegitimate generic name).
Lentin and Williams, 1981, also effected the transfer of this species to Lejeunecysta.
Holotype: Morgenroth 1966, pl.1, fig.8
Age: Early Oligocene
Original Description Lejeunia tenella Morgenroth, 1966
Derivatio nominis: tenellus Latin = delicate.
Holotype: The in Slide H18 preserved and shown on plate 1, fig. 8. Paratypoids: H18/II, HS, Io3 4, Io38.
Locus typicus: Depold'sche Ziegelei (south of Helmstedt).
Stratum typicum: Lower Oligocene
Diagnosis: A species of the genus Lejeunia with a broad, circular girdle furrow, which is bordered by margins of teeth. The smooth, delicate theca is loosely decorated with thorns, which can be arranged in rows.
Description: The delicate, smooth theca has a bilaterally symmetrical pentagonal outline. It is loosely covered with small thorns, which can also be arranged in rows. The circular, fairly wide girdle furrow is slightly depressed. It is bordered on both sides by a border of tiny teeth. A longitudinal furrow is indicated by its ventral interruption. The arch ends in a clearly pointed horn - in one specimen it extends like a tip. The two antapical horns are also very much advanced and pointed.
Dimensions:
Cyst length: 63µ (45µ–84µ)
Cyst width: 52µ (33µ–61µ)
(5 specimens measured)
Comparison: So far, no species of the genus Lejeunia is known whose capsule is covered with thorns.
Remarks: In contrast to the genotype of the genus Ginginodinium COOKSON & EISENACK 1960, the horns are not closed off from the interior. Although the genus diagnosis of Ginginodinium expressly mentions the absence of an inner capsule, EISENACK 1961 mentions that in one specimen "the shell consisted of 2 cases that were clearly distinguishable in places" and that in all specimens the hollow horns were closed off from the interior. The latter finding also points to a delicate inner capsule, albeit one that is very difficult to observe. If this is actually present, then the “genotype” would be a Deflandrea species, so that the genus Ginginodinium would have to be deleted.