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Muderongia simplex ssp. microperforata
Muderongia simplex ssp. microperforata Davey, 1982; Emendation: Monteil, 1991b, p.474, as Muderongia microperforata.
Originally (and now) Muderongia simplex subsp. microperforata, subsequently Muderongia microperforata. Poulsen (1996, p.59) retained this taxon as a subspecies of Muderongia simplex.
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
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.
Affinities:
Davey, 1982, p. 30
M. simplex ssp. microperforata closely resembles M. simplex in all respects except for the very characterstic perforations of the periphragm.
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Muderongia aff. M. simplex subsp. microperforata of Nohr-Hansen 1993
Comments: Nohr-Hansen 1993:
The ends of the lateral horns in the present specimens differs from the type material (Davey, 1982b;
plate 9, figs 4-6) by being more pronounced, in contrast to the holotype which only has shorter bulges. The pointed horn terminations on the lateral horns have also been observed by Harding (1986, plate 17, figs 3, 8). Harding referred his specimens to M. simplex microperforata. Uwins & Batten (1988, plate 34, figs 18, 19) reported specimens from Libya, as Muderongia sp., which also look very similar to the present material. Arhus et al. ( 1990, figs 12D, F) illustrated two specimens which they named Muderongia cf. M. asymmetrica with lateral horn terminations similar to the present material. The marked difference of the morphology in specimens from East Greenland, southern England (Harding,
1986), Libya (Uwins & Batten, 1988) and Barents Sea (Arhus et al., 1990) from the type material of M. simplex microperforata (Davey, 1982b) may indicate that we are dealing with a new subspecies or maybe, more likely, a new species.
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Originally (and now) Muderongia simplex subsp. microperforata, subsequently Muderongia microperforata. Poulsen (1996, p.59) retained this taxon as a subspecies of Muderongia simplex.
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
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.
Affinities:
Davey, 1982, p. 30
M. simplex ssp. microperforata closely resembles M. simplex in all respects except for the very characterstic perforations of the periphragm.
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Muderongia aff. M. simplex subsp. microperforata of Nohr-Hansen 1993
Comments: Nohr-Hansen 1993:
The ends of the lateral horns in the present specimens differs from the type material (Davey, 1982b;
plate 9, figs 4-6) by being more pronounced, in contrast to the holotype which only has shorter bulges. The pointed horn terminations on the lateral horns have also been observed by Harding (1986, plate 17, figs 3, 8). Harding referred his specimens to M. simplex microperforata. Uwins & Batten (1988, plate 34, figs 18, 19) reported specimens from Libya, as Muderongia sp., which also look very similar to the present material. Arhus et al. ( 1990, figs 12D, F) illustrated two specimens which they named Muderongia cf. M. asymmetrica with lateral horn terminations similar to the present material. The marked difference of the morphology in specimens from East Greenland, southern England (Harding,
1986), Libya (Uwins & Batten, 1988) and Barents Sea (Arhus et al., 1990) from the type material of M. simplex microperforata (Davey, 1982b) may indicate that we are dealing with a new subspecies or maybe, more likely, a new species.
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