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Muderongia microperforata
Muderongia microperforata (Davey, 1982) emend. Monteil 1991
Originally Muderongia simplex ssp. microperforata, subsequently (and now) Muderongia microperforata.
Holotype: Davey, 1982, pl. 9, fig. 4-5; Monteil, 1991, pl.2, fig.10
Locus typicus: Haldager No. 1 Borehole, Denmark
Stratum typicum: Late Ryazanian-Early Valanginian
Original description: Davey, 1982, p. 30: Muderongia simplex ssp. microperforata
Diagnosis: A subspecies of M. simplex possessing a perforate periphragm. The perforations are numerous, small and are circular to subpolygonal in outline.
Dimensions: Holotype: overall length, 85 Ám, overall width, 74 Ám. Range: overall length, 78-85 Ám, overall width, 51-70 Ám, overall length (archeopyle developed), 42-60 Ám.
Description (annotated): The perforations are often better developed, and more easily observed, on the horns. Typically an apical horn, two lateral and two antapical horns are present although the lateral horns and one of the antapical horns may be reduced to the bulges. A clear paracingulum is usually present and extends along the lateral horns to give a lateral indentation of them. The inner body is rounded in shape and may be sligthly asymmetric antapically.
Emended diagnosis: Monteil, 1991, p. 474
Cysts proximate, compressed dorsoventrally, two-layered, delphicavate. Pericyst ceratioid, asymmetrical, with 5 usually prominent to slightly differentiated horns: 1 apical (axial, type AP l); 2 subequal lateral (axial, type L I), indented; 2 inequal antapical (joined, type ATP ll). Lateral horns and right antapical horn may be reduced to bulges. Left antapical horn longer (up to one and one-half times) than the right one. Horns normal to tapered with distal extremities closed and rounded; proximal extremities wide. Endocyst oval to rhombic, often with an eccentric antapex or, sometimes with a knob-like protrusion, extending in the left antapical horn. Periphragm thin, completely microperforated. Endophragm thin, psilate to granulate. Archeopyle apical, type (4A), with angular margin. Parasulcal notch marked. Operculum free. Paratabulation indicated only by archeopyle, by pericingulum and by perisulcus. Formula: ?pr, 4", 0a, 6", 6c, 6""", 1p, 1"""". Pericingulum marked by indentation of lateral horns and by parallel transverse structures. Perisulcus marked by parasulcal notch offset. Perisulcal area not observed. Dimensions of the holotype (with operculum): 85 Ám x 74 Ám (overall L x I).
Affinities:
Davey, 1982, p. 30: Muderongia simplex ssp. microperforata
M. simplex ssp. microperforata closely resembles M. simplex in all respects except for the very characterstic perforations of the periphragm.
Monteil, 1991, p. 474: Muderongia microperforata differs from M. perforata in having a completely microperforated periphragm rather than perforated in the distal half of the horns only.
Originally Muderongia simplex ssp. microperforata, subsequently (and now) Muderongia microperforata.
Holotype: Davey, 1982, pl. 9, fig. 4-5; Monteil, 1991, pl.2, fig.10
Locus typicus: Haldager No. 1 Borehole, Denmark
Stratum typicum: Late Ryazanian-Early Valanginian
Original description: Davey, 1982, p. 30: Muderongia simplex ssp. microperforata
Diagnosis: A subspecies of M. simplex possessing a perforate periphragm. The perforations are numerous, small and are circular to subpolygonal in outline.
Dimensions: Holotype: overall length, 85 Ám, overall width, 74 Ám. Range: overall length, 78-85 Ám, overall width, 51-70 Ám, overall length (archeopyle developed), 42-60 Ám.
Description (annotated): The perforations are often better developed, and more easily observed, on the horns. Typically an apical horn, two lateral and two antapical horns are present although the lateral horns and one of the antapical horns may be reduced to the bulges. A clear paracingulum is usually present and extends along the lateral horns to give a lateral indentation of them. The inner body is rounded in shape and may be sligthly asymmetric antapically.
Emended diagnosis: Monteil, 1991, p. 474
Cysts proximate, compressed dorsoventrally, two-layered, delphicavate. Pericyst ceratioid, asymmetrical, with 5 usually prominent to slightly differentiated horns: 1 apical (axial, type AP l); 2 subequal lateral (axial, type L I), indented; 2 inequal antapical (joined, type ATP ll). Lateral horns and right antapical horn may be reduced to bulges. Left antapical horn longer (up to one and one-half times) than the right one. Horns normal to tapered with distal extremities closed and rounded; proximal extremities wide. Endocyst oval to rhombic, often with an eccentric antapex or, sometimes with a knob-like protrusion, extending in the left antapical horn. Periphragm thin, completely microperforated. Endophragm thin, psilate to granulate. Archeopyle apical, type (4A), with angular margin. Parasulcal notch marked. Operculum free. Paratabulation indicated only by archeopyle, by pericingulum and by perisulcus. Formula: ?pr, 4", 0a, 6", 6c, 6""", 1p, 1"""". Pericingulum marked by indentation of lateral horns and by parallel transverse structures. Perisulcus marked by parasulcal notch offset. Perisulcal area not observed. Dimensions of the holotype (with operculum): 85 Ám x 74 Ám (overall L x I).
Affinities:
Davey, 1982, p. 30: Muderongia simplex ssp. microperforata
M. simplex ssp. microperforata closely resembles M. simplex in all respects except for the very characterstic perforations of the periphragm.
Monteil, 1991, p. 474: Muderongia microperforata differs from M. perforata in having a completely microperforated periphragm rather than perforated in the distal half of the horns only.