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Senegalinium aenigmaticum
Senegalinium aenigmaticum (Boltenhagen, 1977) Lentin and Williams, 1981
Originally Deflandrea, subsequently (and now) Senegalinium.
Holotype: Boltenhagen, 1977, pl.14, figs.5a-b
Age: Albian-Turonian
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Original description: [Boltenhagen, 1977] (translated from French):
Deflandrea aenigmatica sp. nov.
Makoc Series and Red Series, Turonian (base) - Cenomanian; Libreville (Gabon, South Africa).
DIAGNOSIA
Very thin theca, with three pronounced conical horns; periphragm covered with hairs implanted on microwarts and partially adherent to the globose capsule. Well-defined circular cingulum, dividing the theca into two equal parts; sulcus sometimes visible. Intercalary archaeopyle of subtriangular outline, with truncated angles.
DESCRIPTION
The theca of this species is formed by an extremely thin and very fragile membrane enclosing a subspherical or ovoid capsule with slightly thicker and sometimes slightly punctate walls. The conical epitheca has a prominent, pointed apical horn. The rounded hypothelium is provided with two smaller, antapical horns, also conical; they are well separated and are of roughly identical dimensions. These horns, due to crumpling of the membrane, are often deformed and sometimes barely perceptible. The cingulum, well individualized in a large number of specimens, is only identifiable in some by lateral notches.
This circular cingulum divides the capsule into two roughly equal parts. The sulcus, quite wide, reaches the base of the antapical horns, but is only rarely clearly visible. The more or less triangular intercalary archaeopyle, with truncated angles, is only exceptionally observable. In the center, tears in the apex region are frequent and it would seem that they are due to the fragility of the membrane around the archaeopyle. The theca membrane sometimes adheres to the capsule, except in the horn region. It is generally more or less floating in most specimens. This membrane is dotted with very fine hairs (3 to 4 μ in length), with tiny warts at the base. These hairs are difficult to see on the theca above the capsule, and sometimes only the basal warts can be seen at 800x magnification and phase contrast. In some places and on some specimens, the hairs or warts are more or less aligned
along preferred directions, which would indicate the beginnings of a tabulation boundary.
PRESERVATION
In a few rare specimens, the ornamental hairs disappear completely, as do almost all of their basal microwarts. These variations are due to the state of preservation of this extremely fragile material. Irregular tears of the theca are frequently observed, which sometimes lead to complete denudation of the capsule.
DIMENSIONS
Holotype: theca (with horns): L x l = 97 x 66 μ
capsule: L x l = 63 x 57 μ
Paratypes: theca: L x l = 80 x 65 μ; 90 x 64 μ; 90 x 62 μ
capsule: L x l = 62 x 54 μ; 64 x 61 μ; 54 x 53 μ
Based on 22 other specimens and their state of conservation:
theca length: 88 - 66; average length: 78 μ
width: 66 - 50; average width: 57 μ
capsule length: 63 - 48; average length: 54 μ
width: 62 - 46; average width: 54 μ
horns - apical: apparent length: 20 - 10 μ
average: 15 μ
antapical: apparent length: 18 - 4 μ
average: 14 μ
COMPARISON
The ornamentation of the species under consideration bears a very close resemblance to that of Palaeohystricophora infusorioides DEFL. 1937, described below. Thus, poorly preserved specimens of these two genera and these two distinct species can easily be confused and, in the absence of the typical comets of Deflandrea, are practically impossible to differentiate with certainty. A fortiori, poorly preserved specimens, which are the most common, can be assimilated to either of the two species under consideration, indiscriminately.
In its general appearance, the species described is very reminiscent of Ascodinium venuscosum COOK. and HUG. 1964 (p. 41, PI. 5, Fig. 5). The difference lies in the position and shape of the archaeopyle and in the ornamentation. Among the various species of the genus Deflandrea, D. macrocysta COOK. et EIS. 1960 (p. 3, PI. I, Fig. 7-8) is quite close to our form, but it differs from it by its ornamentation formed by tight granulation and the position of the cingulum, which divides the theca into two unequal parts.
Furthermore, D. dilwynensis COOK. et EIS. 1965a (PI. 18, Fig. 6-9) resembles the form in question in its outline but differs by the absence of omentation, longitudinal folding, and pronounced cingulum.
Stratigraphic and geographic position.
Upper Cretaceous: Albian (Summit) - Turonian, Gabon (Libreville, North Ogooué, Fernan-Vaz, and Port-Gentil).
Originally Deflandrea, subsequently (and now) Senegalinium.
Holotype: Boltenhagen, 1977, pl.14, figs.5a-b
Age: Albian-Turonian
------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Boltenhagen, 1977] (translated from French):
Deflandrea aenigmatica sp. nov.
Makoc Series and Red Series, Turonian (base) - Cenomanian; Libreville (Gabon, South Africa).
DIAGNOSIA
Very thin theca, with three pronounced conical horns; periphragm covered with hairs implanted on microwarts and partially adherent to the globose capsule. Well-defined circular cingulum, dividing the theca into two equal parts; sulcus sometimes visible. Intercalary archaeopyle of subtriangular outline, with truncated angles.
DESCRIPTION
The theca of this species is formed by an extremely thin and very fragile membrane enclosing a subspherical or ovoid capsule with slightly thicker and sometimes slightly punctate walls. The conical epitheca has a prominent, pointed apical horn. The rounded hypothelium is provided with two smaller, antapical horns, also conical; they are well separated and are of roughly identical dimensions. These horns, due to crumpling of the membrane, are often deformed and sometimes barely perceptible. The cingulum, well individualized in a large number of specimens, is only identifiable in some by lateral notches.
This circular cingulum divides the capsule into two roughly equal parts. The sulcus, quite wide, reaches the base of the antapical horns, but is only rarely clearly visible. The more or less triangular intercalary archaeopyle, with truncated angles, is only exceptionally observable. In the center, tears in the apex region are frequent and it would seem that they are due to the fragility of the membrane around the archaeopyle. The theca membrane sometimes adheres to the capsule, except in the horn region. It is generally more or less floating in most specimens. This membrane is dotted with very fine hairs (3 to 4 μ in length), with tiny warts at the base. These hairs are difficult to see on the theca above the capsule, and sometimes only the basal warts can be seen at 800x magnification and phase contrast. In some places and on some specimens, the hairs or warts are more or less aligned
along preferred directions, which would indicate the beginnings of a tabulation boundary.
PRESERVATION
In a few rare specimens, the ornamental hairs disappear completely, as do almost all of their basal microwarts. These variations are due to the state of preservation of this extremely fragile material. Irregular tears of the theca are frequently observed, which sometimes lead to complete denudation of the capsule.
DIMENSIONS
Holotype: theca (with horns): L x l = 97 x 66 μ
capsule: L x l = 63 x 57 μ
Paratypes: theca: L x l = 80 x 65 μ; 90 x 64 μ; 90 x 62 μ
capsule: L x l = 62 x 54 μ; 64 x 61 μ; 54 x 53 μ
Based on 22 other specimens and their state of conservation:
theca length: 88 - 66; average length: 78 μ
width: 66 - 50; average width: 57 μ
capsule length: 63 - 48; average length: 54 μ
width: 62 - 46; average width: 54 μ
horns - apical: apparent length: 20 - 10 μ
average: 15 μ
antapical: apparent length: 18 - 4 μ
average: 14 μ
COMPARISON
The ornamentation of the species under consideration bears a very close resemblance to that of Palaeohystricophora infusorioides DEFL. 1937, described below. Thus, poorly preserved specimens of these two genera and these two distinct species can easily be confused and, in the absence of the typical comets of Deflandrea, are practically impossible to differentiate with certainty. A fortiori, poorly preserved specimens, which are the most common, can be assimilated to either of the two species under consideration, indiscriminately.
In its general appearance, the species described is very reminiscent of Ascodinium venuscosum COOK. and HUG. 1964 (p. 41, PI. 5, Fig. 5). The difference lies in the position and shape of the archaeopyle and in the ornamentation. Among the various species of the genus Deflandrea, D. macrocysta COOK. et EIS. 1960 (p. 3, PI. I, Fig. 7-8) is quite close to our form, but it differs from it by its ornamentation formed by tight granulation and the position of the cingulum, which divides the theca into two unequal parts.
Furthermore, D. dilwynensis COOK. et EIS. 1965a (PI. 18, Fig. 6-9) resembles the form in question in its outline but differs by the absence of omentation, longitudinal folding, and pronounced cingulum.
Stratigraphic and geographic position.
Upper Cretaceous: Albian (Summit) - Turonian, Gabon (Libreville, North Ogooué, Fernan-Vaz, and Port-Gentil).