Back
Andalusiella mauthei ssp. mauthei
Andalusiella mauthei ssp. mauthei, Riegel, 1974; Emend. Riegel and Sarjeant, 1982
Autonym.
See also Alterbia (combination illegitimate).
Tax. jr. synonym of Andalusiella polymorpha (Malloy, 1972) Lentin and Williams, 1977b, according to Lentin and Williams, 1976. Lentin and Williams, 1977b, retained Andalusiella mauthei as a separate species.
Holotype: Riegel, 1974, pl.2, fig.4; Riegel and Sarjeant, 1982, figs.1A-C, 4A, 5A
Locus typicus: Puerto de Bolonia, Province of Cadiz, Spain
Stratum typicum: Senonian?
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Riegel, 1974, p. 357-360]
Diagnosis:
Shell outline oval to rhomboidal with long tapering apical horn and two coritiguous unequal antapical horns. Right antapical horn long, left horn short and pointing ventrally and outward. Darkened rings around bases of horns. Girdle shallow, bordered on either side by a low ledge and a row of small tubercles. No well defined capsule.
Archeopyle intercalary, six-sided with alternating long and short sides.
Shell surface smooth to slightly granular or wrinkled. Colour brown.
Original description:
The outline of the shell is most commonly rounded-rhomboidal with epi-and hypotract of about equal size. The cysts appear to have been originally rather flat and only somewhat inflated dorsally since only one or two dorsal transverse compression folds and hardly any longitudinal folds are formed.
The apical horn is slender, tapering and slightly blunted at its tip. Its length measures to 3 times the width at base and between 1/3 to 1/4 of the length of the cyst body. In some specimens the apical horn bears a tiny three-pointed crown at its tip. The large antapical horn is more pointed and slightly shorter than the apical horn, and shifted somewhat to the right of the antapex. Immediately adjacent to its left side and enclosing an acute angle with it is the small horn, about even-sided triangular in outline, and inserted somewhat to the left of the antapex, its axis pointing somewhat ventrally and away from the adjacent long horn.
The cyst wall consists of an inner layer, about 1 to 2 µm in thickness and distinctly brown in colour, and a very thin outer membrane which is closely fused with the inner layer separating slightly from it only in the horns of most specimens. The inner layer thickens around the apex and antapex of the body forming darkened rings around the bases of horns. From that a flattened extension of the inner cyst wall projects into the horns nearly or completely filling them. The observed structure of the horns closely corresponds to the one described by Malloy (1972, text-fig. 2) for his Svalbardella Palaeocystodinium lineage. The shell surface is essentially smooth to finely granular and often appears longitudinally wrinkled in the girdle region. In some well preserved specimens faint traces of plate boundaries can be seen on the dorsal side of the hypotract and around the archeopyle reflecting a peridinoid tabulation. A few specimens suggest differentiation into more granulated plate areas and less granulated intercalary zones. The weakly helicoidal girdle always shows up as a darkened zone. In well preserved specimens it forms a shallow depression bordered on either side by a fine ledge which is accompanied externally by a parallel row of tiny tubercles (see SEM micrograph, pl. 2, fig. 2). Width of girdle (distance between ledges): 3-5 µm.
The sulcus is broader and short and cutlined only by two minor folds. Toward the left, near the juncture with the girdle the sulcus bears a characteristic flagellar marking which consists of a shallow oval pit bordered by a flat annulus and showing two elongate projections, one in the center of the pit, the other at its left margin.
The intercalary archeopyle is rather variable in size. Its outline is clearly visible even with the operculum in place, forming an even-sided triangle with truncated corners.
Dimensions:
Holotype: Total length 152 µm, body length 101 µm, width 82 µm.
Range of length including horns: 103-176 µm; mean: 146.0 µm; standard deviation: 12.4.
Range of body length: 72-115 µm; mean: 92.8 µm; standard deviation: 6.3. (58 specimens measured.)
Affinities:
A. mauthei shows some striking similarities with forms described from the Cretaceous of Gabon (Africa) by Malloy (1972) and assigned to Svalbardella australina (Cookson) Malloy and S. polymorpha Malloy. These forms appear to differ from A. mauthei only by a larger ratio of length to width, by the shape of the antapical horns and by the general lack of a girdle.
The flagellar markings are not mentioned by Malloy, but show on photographs of both forms. A. mauthei easily fits into the Svalbardella - Palaeocystodinium lineage proposed by Malloy (between his morphotypes B and C, i. e. Svalbardella polymorpha and S. australina respectively). However, Svalbardella Manum 1960 and Palaeocystodinium Alberti 1961 have been originally described with single antapical horns and an oval capsule clearly separated from the horn-bearing outer cyst wall. Thus Malloys forms would seem to differ sufficiently from the two genera with regard to the development of capsule and horns to be reassigned to the new genus. The precise delimitation of these forms into species, however, should await closer comparison of material.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended diagnosis:
Riegel and Sarjeant, 1982, p. 289:
Diagnosis:
Cyst ovoidal to rounded-rhomboidal, proximate, acrocavate, with apical horn strongly developed and having an apicular structure (broken off in many specimens). Right antapical horn of comparable length or slightly shorter, left antapical horn very much shorter and sometimes poorly marked. The bases of all three horns may be closed by thickened plugs, the endophragm extending almost to the horn tips (although clearly separate from the periphragm). Paracingulum shallow, bordered by a low ridge and a row of small tubercles, low ridges may also outline other paraplates. Paraplate 2a, lost in archaeopyle formation, is essentially of standard hexa form but with an apexward elongation of its left and right anterior sides and a shortening of its apical margin. Surface of cysts smooth to slightly granular or wrinkled.
Autonym.
See also Alterbia (combination illegitimate).
Tax. jr. synonym of Andalusiella polymorpha (Malloy, 1972) Lentin and Williams, 1977b, according to Lentin and Williams, 1976. Lentin and Williams, 1977b, retained Andalusiella mauthei as a separate species.
Holotype: Riegel, 1974, pl.2, fig.4; Riegel and Sarjeant, 1982, figs.1A-C, 4A, 5A
Locus typicus: Puerto de Bolonia, Province of Cadiz, Spain
Stratum typicum: Senonian?
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Riegel, 1974, p. 357-360]
Diagnosis:
Shell outline oval to rhomboidal with long tapering apical horn and two coritiguous unequal antapical horns. Right antapical horn long, left horn short and pointing ventrally and outward. Darkened rings around bases of horns. Girdle shallow, bordered on either side by a low ledge and a row of small tubercles. No well defined capsule.
Archeopyle intercalary, six-sided with alternating long and short sides.
Shell surface smooth to slightly granular or wrinkled. Colour brown.
Original description:
The outline of the shell is most commonly rounded-rhomboidal with epi-and hypotract of about equal size. The cysts appear to have been originally rather flat and only somewhat inflated dorsally since only one or two dorsal transverse compression folds and hardly any longitudinal folds are formed.
The apical horn is slender, tapering and slightly blunted at its tip. Its length measures to 3 times the width at base and between 1/3 to 1/4 of the length of the cyst body. In some specimens the apical horn bears a tiny three-pointed crown at its tip. The large antapical horn is more pointed and slightly shorter than the apical horn, and shifted somewhat to the right of the antapex. Immediately adjacent to its left side and enclosing an acute angle with it is the small horn, about even-sided triangular in outline, and inserted somewhat to the left of the antapex, its axis pointing somewhat ventrally and away from the adjacent long horn.
The cyst wall consists of an inner layer, about 1 to 2 µm in thickness and distinctly brown in colour, and a very thin outer membrane which is closely fused with the inner layer separating slightly from it only in the horns of most specimens. The inner layer thickens around the apex and antapex of the body forming darkened rings around the bases of horns. From that a flattened extension of the inner cyst wall projects into the horns nearly or completely filling them. The observed structure of the horns closely corresponds to the one described by Malloy (1972, text-fig. 2) for his Svalbardella Palaeocystodinium lineage. The shell surface is essentially smooth to finely granular and often appears longitudinally wrinkled in the girdle region. In some well preserved specimens faint traces of plate boundaries can be seen on the dorsal side of the hypotract and around the archeopyle reflecting a peridinoid tabulation. A few specimens suggest differentiation into more granulated plate areas and less granulated intercalary zones. The weakly helicoidal girdle always shows up as a darkened zone. In well preserved specimens it forms a shallow depression bordered on either side by a fine ledge which is accompanied externally by a parallel row of tiny tubercles (see SEM micrograph, pl. 2, fig. 2). Width of girdle (distance between ledges): 3-5 µm.
The sulcus is broader and short and cutlined only by two minor folds. Toward the left, near the juncture with the girdle the sulcus bears a characteristic flagellar marking which consists of a shallow oval pit bordered by a flat annulus and showing two elongate projections, one in the center of the pit, the other at its left margin.
The intercalary archeopyle is rather variable in size. Its outline is clearly visible even with the operculum in place, forming an even-sided triangle with truncated corners.
Dimensions:
Holotype: Total length 152 µm, body length 101 µm, width 82 µm.
Range of length including horns: 103-176 µm; mean: 146.0 µm; standard deviation: 12.4.
Range of body length: 72-115 µm; mean: 92.8 µm; standard deviation: 6.3. (58 specimens measured.)
Affinities:
A. mauthei shows some striking similarities with forms described from the Cretaceous of Gabon (Africa) by Malloy (1972) and assigned to Svalbardella australina (Cookson) Malloy and S. polymorpha Malloy. These forms appear to differ from A. mauthei only by a larger ratio of length to width, by the shape of the antapical horns and by the general lack of a girdle.
The flagellar markings are not mentioned by Malloy, but show on photographs of both forms. A. mauthei easily fits into the Svalbardella - Palaeocystodinium lineage proposed by Malloy (between his morphotypes B and C, i. e. Svalbardella polymorpha and S. australina respectively). However, Svalbardella Manum 1960 and Palaeocystodinium Alberti 1961 have been originally described with single antapical horns and an oval capsule clearly separated from the horn-bearing outer cyst wall. Thus Malloys forms would seem to differ sufficiently from the two genera with regard to the development of capsule and horns to be reassigned to the new genus. The precise delimitation of these forms into species, however, should await closer comparison of material.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended diagnosis:
Riegel and Sarjeant, 1982, p. 289:
Diagnosis:
Cyst ovoidal to rounded-rhomboidal, proximate, acrocavate, with apical horn strongly developed and having an apicular structure (broken off in many specimens). Right antapical horn of comparable length or slightly shorter, left antapical horn very much shorter and sometimes poorly marked. The bases of all three horns may be closed by thickened plugs, the endophragm extending almost to the horn tips (although clearly separate from the periphragm). Paracingulum shallow, bordered by a low ridge and a row of small tubercles, low ridges may also outline other paraplates. Paraplate 2a, lost in archaeopyle formation, is essentially of standard hexa form but with an apexward elongation of its left and right anterior sides and a shortening of its apical margin. Surface of cysts smooth to slightly granular or wrinkled.