Back
Areoligera undulata
Areoligera undulata, Eaton, 1976
Originally (and now) Areoligera, subsequently Glaphyrocysta?.
Stover and Evitt, 1978, transferred this species to Glaphyrocysta Stover and Evitt, 1978. Jain and Garg, 1986, retained it in Areoligera.
Holotype: Eaton, 1976, pl.4, figs.4,6; Bujak et al., 1980, pl.9, figs.7-8
Locus typicus: Bracklesham Beds, Alum Bay, Isle of Wight, England.
Stratum typicum: Middle-Late Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eaton, 1976, p. 248]:
Diagnosis:
Cyst body dorsoventrally flattened with a smooth of finely granular surface. The circular or subcircular outline may be modified by the development of one or two antapical protuberances. Ventral and dorsal surfaces bear sail-like membranes with lobate undulating distal margins. Ventral membrane restricted to the peripheral zone, aligned parallel to, and situated close to, the margin of the cyst body. Dorsal membranes organized into process complexes which may be arcuate, soleate or annular on the pre- and postcingular zones, linear on the cingular zone, and annular on the antapical zone.
Archaeopyle apical, tetratabular.
Dimensions:
Holotype: cyst body (without operculum) 56x82 µm; height of membrane up to 30 µm.
Observed range: cyst body (without operculum) 52x54 µm to 73x92 µm; (complete) 66x68Á to 75x75 µm; height of membrane up to 32 µm. (n = 25).
Affinities:
A specimen assignable to Areoligera undulata was recorded from the Upper Eocene of East Prussia by Eisenack (1954), described in the text as Palmnickia sp. indet., and on the plate explanation as Palmnickia sp. ex aff. Iobifera (Eisenack 1954: 70; pl. I2, fig. 20). Evitt (1961: 400; pl. 8, figs 16--17; pl. 9, figs 8-10) illustrated and described the specimen recorded by Eisenack, and commented on its affinities with the genus Areoligera, noting in particular the overall shape and the distribution of the processes.
The textural appearance of the membranes, and the variation in the type of process complex developed on the dorsal surface in A. undulata, are similar to those of A. sentosa n. sp. A few specimens have been recorded in which all the pre- and postcingular complexes are annular, while in some forms they are all arcuate. No forms have been recorded with process complexes developed on the ventral surface, although in one specimen there is some loss of proximal continuity in the membrane on the ventral surface. The undulating nature of the distal margin of the sail-like membranes and the absence of distal spines distinguish A. undulata from A. sentosa and A. tauloma.
Originally (and now) Areoligera, subsequently Glaphyrocysta?.
Stover and Evitt, 1978, transferred this species to Glaphyrocysta Stover and Evitt, 1978. Jain and Garg, 1986, retained it in Areoligera.
Holotype: Eaton, 1976, pl.4, figs.4,6; Bujak et al., 1980, pl.9, figs.7-8
Locus typicus: Bracklesham Beds, Alum Bay, Isle of Wight, England.
Stratum typicum: Middle-Late Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eaton, 1976, p. 248]:
Diagnosis:
Cyst body dorsoventrally flattened with a smooth of finely granular surface. The circular or subcircular outline may be modified by the development of one or two antapical protuberances. Ventral and dorsal surfaces bear sail-like membranes with lobate undulating distal margins. Ventral membrane restricted to the peripheral zone, aligned parallel to, and situated close to, the margin of the cyst body. Dorsal membranes organized into process complexes which may be arcuate, soleate or annular on the pre- and postcingular zones, linear on the cingular zone, and annular on the antapical zone.
Archaeopyle apical, tetratabular.
Dimensions:
Holotype: cyst body (without operculum) 56x82 µm; height of membrane up to 30 µm.
Observed range: cyst body (without operculum) 52x54 µm to 73x92 µm; (complete) 66x68Á to 75x75 µm; height of membrane up to 32 µm. (n = 25).
Affinities:
A specimen assignable to Areoligera undulata was recorded from the Upper Eocene of East Prussia by Eisenack (1954), described in the text as Palmnickia sp. indet., and on the plate explanation as Palmnickia sp. ex aff. Iobifera (Eisenack 1954: 70; pl. I2, fig. 20). Evitt (1961: 400; pl. 8, figs 16--17; pl. 9, figs 8-10) illustrated and described the specimen recorded by Eisenack, and commented on its affinities with the genus Areoligera, noting in particular the overall shape and the distribution of the processes.
The textural appearance of the membranes, and the variation in the type of process complex developed on the dorsal surface in A. undulata, are similar to those of A. sentosa n. sp. A few specimens have been recorded in which all the pre- and postcingular complexes are annular, while in some forms they are all arcuate. No forms have been recorded with process complexes developed on the ventral surface, although in one specimen there is some loss of proximal continuity in the membrane on the ventral surface. The undulating nature of the distal margin of the sail-like membranes and the absence of distal spines distinguish A. undulata from A. sentosa and A. tauloma.