Back
Polygonifera eisenackii
Polygonifera eisenackii Mehrota and Sarjeant, 1984
Now Platycystidia. Originally Polygonifera, subsequently Leberidocysta?, thirdly (and now) Platycystidia.
Holotype: Mehrota and Sarjeant, 1984, pl.1, fig.6; text-fig. 1c
Locus typicus: Perivadavadi shallow well- 1, Cauvery basin, South India
Stratum typicum: Aptian
Original diagnosis: Mehrota and Sarjeant, 1984, p. 46
Cyst proximate, camocavate. Periblast polygonal-subpolygonal or oval in ambitus, oval in lateral view; endoblast oval to broadly ellipsoidal. Apical horn lacking; a small notch may develop in the apical region, due to periphragm folding. Periphragm thin, delicate; it may be fully, partially or not at all developed and, when present, is typically folded. Endophragm relatively thicker and typically not distorted. Both endophragm and periphragm are smooth or weakly ornamented (reticulate, foveoreticulate, or finely punctate). No parasutural features are present. Archaeopyle apical, (4a)/(4a); peripyle and endopyle are usually distinct. Operculum free or attached. Cingulum indicated by periphragm folding, sometimes distinct and completely developed, in other instances faintly, incompletely or not at all suggested. Typically, no indication of a sulcus is seen other than a poorly marked sulcal notch. A claustrum of variable size and shape may be present in the hypotract.
Dimensions. Holotype (operculum attached); periblast 89 x 50 µm; endoblast 68 x 39 µm. Paratype a (operculum attached); periblast 55 x 40 µm; endoblast 45 x 32 µm. Paratype b (operculum attached); periblast 92 x 63 µm; endoblast 61 x 45 µm. Range" (operculum free); periblast 50 x 48 µm to 92 x 73 µm, endoblast 40 x 35 to 61 x 45 µm. A single specimen (Pl. 2, fig. 6) measured with periblast partially developed, endoblast complete with attached operculum; endoblast 42 x 37 µm.
Affinities:
Mehrota and Sarjeant, 1984, p. 48: This species is readily distinguishable from P. evittii and P. (ex: Hexagonifera) chlamydata by its laevigate to weakly ornamented endoblast. The endoblast ornamentation in P. evittii is scabrate to granulose and that in P. chlamydata is verrucose. The degree of development of the cingulum is variable in P. eisenackii, whereas the cingulum is well developed in P. evittii (Habib,1972, pl.5, figs.1,2) and not developed at all in P. chlamydata (Cookson & Eisenack, 1962, pl. 7, figs. 1-3, 5-8.).
Now Platycystidia. Originally Polygonifera, subsequently Leberidocysta?, thirdly (and now) Platycystidia.
Holotype: Mehrota and Sarjeant, 1984, pl.1, fig.6; text-fig. 1c
Locus typicus: Perivadavadi shallow well- 1, Cauvery basin, South India
Stratum typicum: Aptian
Original diagnosis: Mehrota and Sarjeant, 1984, p. 46
Cyst proximate, camocavate. Periblast polygonal-subpolygonal or oval in ambitus, oval in lateral view; endoblast oval to broadly ellipsoidal. Apical horn lacking; a small notch may develop in the apical region, due to periphragm folding. Periphragm thin, delicate; it may be fully, partially or not at all developed and, when present, is typically folded. Endophragm relatively thicker and typically not distorted. Both endophragm and periphragm are smooth or weakly ornamented (reticulate, foveoreticulate, or finely punctate). No parasutural features are present. Archaeopyle apical, (4a)/(4a); peripyle and endopyle are usually distinct. Operculum free or attached. Cingulum indicated by periphragm folding, sometimes distinct and completely developed, in other instances faintly, incompletely or not at all suggested. Typically, no indication of a sulcus is seen other than a poorly marked sulcal notch. A claustrum of variable size and shape may be present in the hypotract.
Dimensions. Holotype (operculum attached); periblast 89 x 50 µm; endoblast 68 x 39 µm. Paratype a (operculum attached); periblast 55 x 40 µm; endoblast 45 x 32 µm. Paratype b (operculum attached); periblast 92 x 63 µm; endoblast 61 x 45 µm. Range" (operculum free); periblast 50 x 48 µm to 92 x 73 µm, endoblast 40 x 35 to 61 x 45 µm. A single specimen (Pl. 2, fig. 6) measured with periblast partially developed, endoblast complete with attached operculum; endoblast 42 x 37 µm.
Affinities:
Mehrota and Sarjeant, 1984, p. 48: This species is readily distinguishable from P. evittii and P. (ex: Hexagonifera) chlamydata by its laevigate to weakly ornamented endoblast. The endoblast ornamentation in P. evittii is scabrate to granulose and that in P. chlamydata is verrucose. The degree of development of the cingulum is variable in P. eisenackii, whereas the cingulum is well developed in P. evittii (Habib,1972, pl.5, figs.1,2) and not developed at all in P. chlamydata (Cookson & Eisenack, 1962, pl. 7, figs. 1-3, 5-8.).