Back
Membranigonyaulax promineseptatum
Membranigonyaulax promineseptata Slimani, 1994, p.21-22, pl.2, figs.13-14,21-23.
Holotype: Slimani, 1994, pl.2, figs.21-23.
Age: Late Campanian.
------------------------------------------------------------------------------------------------------------------------------------------------------
Original description (Slimani, 1994) (translated from French):
Membranigonyaulax promineseptatum sp.nov. (Pl. 2, Fig. 13, 14, 21-23)
Name derivation: Latin: prominens, protruding, protruding parasutural septa.
Holotype: Turnhout -933 m, preparation 6, E.F. coordinate T27/1
Type locality: Turnhout -933 m.
Type horizon: Campanian
Diagnosis: Intermediate-sized Membranigonyaulax cyst with a subcircular to oval endocyst and a very fragile ectophragm supported by parasutural membranous septa and not by intertabular septa and processes (one per plate), the height of which is approximately 1/5 of the total cyst diameter. The paratabulation corresponds to the formula: 4', 6'', 6c, 5''', 1p, pv, 1''''.
Dimensions:
Holotype: central body, length: 40 µm, width: 36 µm; pericyst, length: 70 µm, width: 65 µm
Variations: endocyst: length: 39-42 µm, width: 36-40 µm; entire cyst, length: 58-70 µm, width: 56-60 µm
Number of specimens measured: 14
Material: 20 specimens.
Description: The cyst is holocavate. The endophragm and periphragm are smooth and adjacent. The ectophrage is thin, smooth, fragile, and often detached: the supporting septa are membranous, smooth, and prominent (10 to 15 µm high). Secondary septa, when present, are often located on the margins of the paraplates; the processes are hollow or solid (average diameter 3 µm), distally protruding, and located in the center of the paraplates. The hypocystal configuration of the cyst is quinquiform. The segmented paracingulum (6 to 10 µm wide), devoid of intratabular structures, is apparently laevorotatory. The parasulcus is indicated ventrally by an unsegmented longitudinal surface. The archaeopyle is apical type (4A) (20 to 28 µm wide) with a hexagonal margin and a deep ventral sulcal notch. The operculum is attached or free. Comparison: Membranigonyaulax promineseptatum sp.nov. is characterized primarily by prominent membranous septa; it differs from Membranigonyaulax wilsonii sp.nov., which is smaller, has much lower parasutural ridges, and intratabular areas that always lack secondary septa.
Stratigraphic distribution: Beutenaken: scales 4 and 5, Upper Campanian (B. mucronata Zone). Turnhout: -933 m, Upper Campanian.
Holotype: Slimani, 1994, pl.2, figs.21-23.
Age: Late Campanian.
------------------------------------------------------------------------------------------------------------------------------------------------------
Original description (Slimani, 1994) (translated from French):
Membranigonyaulax promineseptatum sp.nov. (Pl. 2, Fig. 13, 14, 21-23)
Name derivation: Latin: prominens, protruding, protruding parasutural septa.
Holotype: Turnhout -933 m, preparation 6, E.F. coordinate T27/1
Type locality: Turnhout -933 m.
Type horizon: Campanian
Diagnosis: Intermediate-sized Membranigonyaulax cyst with a subcircular to oval endocyst and a very fragile ectophragm supported by parasutural membranous septa and not by intertabular septa and processes (one per plate), the height of which is approximately 1/5 of the total cyst diameter. The paratabulation corresponds to the formula: 4', 6'', 6c, 5''', 1p, pv, 1''''.
Dimensions:
Holotype: central body, length: 40 µm, width: 36 µm; pericyst, length: 70 µm, width: 65 µm
Variations: endocyst: length: 39-42 µm, width: 36-40 µm; entire cyst, length: 58-70 µm, width: 56-60 µm
Number of specimens measured: 14
Material: 20 specimens.
Description: The cyst is holocavate. The endophragm and periphragm are smooth and adjacent. The ectophrage is thin, smooth, fragile, and often detached: the supporting septa are membranous, smooth, and prominent (10 to 15 µm high). Secondary septa, when present, are often located on the margins of the paraplates; the processes are hollow or solid (average diameter 3 µm), distally protruding, and located in the center of the paraplates. The hypocystal configuration of the cyst is quinquiform. The segmented paracingulum (6 to 10 µm wide), devoid of intratabular structures, is apparently laevorotatory. The parasulcus is indicated ventrally by an unsegmented longitudinal surface. The archaeopyle is apical type (4A) (20 to 28 µm wide) with a hexagonal margin and a deep ventral sulcal notch. The operculum is attached or free. Comparison: Membranigonyaulax promineseptatum sp.nov. is characterized primarily by prominent membranous septa; it differs from Membranigonyaulax wilsonii sp.nov., which is smaller, has much lower parasutural ridges, and intratabular areas that always lack secondary septa.
Stratigraphic distribution: Beutenaken: scales 4 and 5, Upper Campanian (B. mucronata Zone). Turnhout: -933 m, Upper Campanian.