Back
Andalusiella polymorpha ssp. aegyptiaca
From Fensome et al., 2019:
Andalusiella polymorpha ssp. aegyptiaca, Schrank, 1988, p.131–132, pl.1, figs.1–6.
Holotype: Schrank, 1988, pl.1, fig.1.
NOW Andalusiella mauthei subsp. aegyptiaca.
Originally Andalusiella polymorpha subsp. aegyptiaca, subsequently (and now) Andalusiella mauthei subsp. aegyptiaca.
Age: late Campanian.
Type locality and horizon: Phosphate mine Abu Shigaila about 20 km NW of Quseir at the Red Sea coast, shale intercalation in the lower part (Hamadat bed) of the Duwi (Phosphate) Formation, see section in Fig.2
---------------------------------------------------------------------------------------------------
Original description: [Schrank, 1988, p.131-132]
Diagnosis:
A subspecies of Andalusiella polymorpha with relatively short horns; antapical horns closely spaced together; left antapical horn of subtriangular shape, right antapical horn reduced to a tiny thorn.
Description:
Cyst ovoidal to rounded rhomboidal or subspherical to ellipsoidal, cornucavate, but very fragile extensions of the endophragm may reach into the horns.
Apical and left antapical horn of comparable size, the right antapical horn is much shorter, typically reduced to a tiny thorn which is in contact with or very close to the base of the larger horn. Cyst length without horns about 70 to 85 µm of its overall length.
Paracingulum, if present, marked by shallow folds or two rows of tiny tubercles.
Archaeopyle intercalary of the standard hexa form of Lentin and Williams (1976) corresponding to the iso-deltaform shape of Bujak and Davies (1983).
On the ventral surface a sulcus may be indicated together with a characteristic beanshaped scar situated at the juncture with the girdle region. Riegel (1974) interpreted such a scar as a flagellar marking in Andalusiella mauthei. Cyst surface smooth or rarely weakly granular.
Dimensions:
Holotype, overall length 117 μm, length without horns 90 μm, width 73 μm.
Range of dimensions: Unoxidized cysts overall length 96-149 μm (mean 124 μm), width 64-81 μm (mean 72 μm), 27 specimens measured; oxidized and KOH treated cysts overall length 100-139 μm (mean 123 μm), width 70-88 μm (mean 77 μm), 21 specimens measured.
Remarks:
The above description is based on unoxidized cysts. HNO3 oxidation and subsequent KOH treatment cause the usual periphragm expansion which results in the formation of seemingly circumcavate cysts with broader horns (Plate I, 3, 5). The originally brown endophragm simultaneously becomes pale.
Affinities/Differential diagnosis:
Andalusiella polymorpha aegyptiaca differs from A.p. polymorpha (see Malloy, 1972, pt.1, figs.8-16, 21) in its more globular shape, in the development of the antapical horns which are spaced closer together with a more reduced right antapical horn, and in the subtriangular shape of the horns. Andalusiella polymorpha aegyptiaca is distinguished from A. mauthei Riegel, 1974 (see Riegel and Sarjeant, 1982, figs.l-6) by its smaller mean size, shorter horns and by its cornucavate cyst. The last feature provides the main difference between these two otherwise closely comparable taxa because the cysts of A. mauthei are typically acrocavate, i.e. they possess outbulges of the endophragm extending into the horns. Such outbulges are generally lacking in A.p. aegyptiaca. The new subspecies represents a transitional form between normal-spined Andalusiella species mentioned above and A.? dubia (Jain et Millepied, 1973) Lentin et Williams, 1980 in which the antapical horns are lacking totally.
Andalusiella polymorpha ssp. aegyptiaca, Schrank, 1988, p.131–132, pl.1, figs.1–6.
Holotype: Schrank, 1988, pl.1, fig.1.
NOW Andalusiella mauthei subsp. aegyptiaca.
Originally Andalusiella polymorpha subsp. aegyptiaca, subsequently (and now) Andalusiella mauthei subsp. aegyptiaca.
Age: late Campanian.
Type locality and horizon: Phosphate mine Abu Shigaila about 20 km NW of Quseir at the Red Sea coast, shale intercalation in the lower part (Hamadat bed) of the Duwi (Phosphate) Formation, see section in Fig.2
---------------------------------------------------------------------------------------------------
Original description: [Schrank, 1988, p.131-132]
Diagnosis:
A subspecies of Andalusiella polymorpha with relatively short horns; antapical horns closely spaced together; left antapical horn of subtriangular shape, right antapical horn reduced to a tiny thorn.
Description:
Cyst ovoidal to rounded rhomboidal or subspherical to ellipsoidal, cornucavate, but very fragile extensions of the endophragm may reach into the horns.
Apical and left antapical horn of comparable size, the right antapical horn is much shorter, typically reduced to a tiny thorn which is in contact with or very close to the base of the larger horn. Cyst length without horns about 70 to 85 µm of its overall length.
Paracingulum, if present, marked by shallow folds or two rows of tiny tubercles.
Archaeopyle intercalary of the standard hexa form of Lentin and Williams (1976) corresponding to the iso-deltaform shape of Bujak and Davies (1983).
On the ventral surface a sulcus may be indicated together with a characteristic beanshaped scar situated at the juncture with the girdle region. Riegel (1974) interpreted such a scar as a flagellar marking in Andalusiella mauthei. Cyst surface smooth or rarely weakly granular.
Dimensions:
Holotype, overall length 117 μm, length without horns 90 μm, width 73 μm.
Range of dimensions: Unoxidized cysts overall length 96-149 μm (mean 124 μm), width 64-81 μm (mean 72 μm), 27 specimens measured; oxidized and KOH treated cysts overall length 100-139 μm (mean 123 μm), width 70-88 μm (mean 77 μm), 21 specimens measured.
Remarks:
The above description is based on unoxidized cysts. HNO3 oxidation and subsequent KOH treatment cause the usual periphragm expansion which results in the formation of seemingly circumcavate cysts with broader horns (Plate I, 3, 5). The originally brown endophragm simultaneously becomes pale.
Affinities/Differential diagnosis:
Andalusiella polymorpha aegyptiaca differs from A.p. polymorpha (see Malloy, 1972, pt.1, figs.8-16, 21) in its more globular shape, in the development of the antapical horns which are spaced closer together with a more reduced right antapical horn, and in the subtriangular shape of the horns. Andalusiella polymorpha aegyptiaca is distinguished from A. mauthei Riegel, 1974 (see Riegel and Sarjeant, 1982, figs.l-6) by its smaller mean size, shorter horns and by its cornucavate cyst. The last feature provides the main difference between these two otherwise closely comparable taxa because the cysts of A. mauthei are typically acrocavate, i.e. they possess outbulges of the endophragm extending into the horns. Such outbulges are generally lacking in A.p. aegyptiaca. The new subspecies represents a transitional form between normal-spined Andalusiella species mentioned above and A.? dubia (Jain et Millepied, 1973) Lentin et Williams, 1980 in which the antapical horns are lacking totally.