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Membranilarnacia wetzelii
Membranilarnacia wetzelii Cookson and Eisenack, 1982
Originally Membranilarnacia, subsequently Membranilarnacia?.
Questionable assignment: Lachkar and Masure in Fauconnier and Masure (2004, p.390) as a problematic species; these authors recommended that the name be restricted to the type material.
Holotype: Cookson and Eisenack, 1982, pl.5, fig.3
Age: Albian-Cenomanian
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Original description: [Cookson and Eisenack, 1982] (translated from German):
Membranilarnacia wetzeli n. sp.
Plate 5, Fig. 3; and? Plate 6, Fig. 16
? 1933 Membranilarnax pterospermoides - O. WETZEL, 1933, p. 52; Plate 6 Figs. 1, 2.
Type: The specimen shown on Plate 5, Fig. 3 and preserved in specimen Balcatta 170/7.
Diagnosis: Central shell spherical, with numerous radial appendages that branch out at the end in a fork-like or anchor-like manner and enclose an almost concentric, delicate outer shell. Their length is less than the radius of the central shell; moreover, they are not of equal length, but are noticeably shorter on one side than the other, with gradual transitions.
Dimensions: Central shell approx. 60 mm, total diameter approx. 90 μ; Length of appendages 10-20 μ. The second specimen has similar dimensions.
Remarks: The species is similar to the flint inclusion Membranilarnax pterospermoides described by O. Wetzel, the type of its genus Membranilarnax. However, since the genus M. was ambiguously defined and had to be abolished because the flint fragment containing the type was lost (EISENACK, 1959, 1963), no clarity can be gained about the structure of M. pterospermoides, and one can only judge from the illustration. I attach no importance to the oval shape of M. pterospermoides, and thus it seems to me that M. wetzeli is identical to M. pterospermoides.
The second specimen is less well preserved, especially with regard to the struts (Plate 6, Fig. 16). In both specimens, the thin outer shell is partially destroyed and folded, especially in the second specimen.
Occurrence: Both specimens from the Balcatta No. 1 borehole; Fig. 3 on Plate 5 at 170 ft. and Fig. 16 on Plate 6 at 180-210 ft., Osborne Formation, Albian-Cenomanian.
Originally Membranilarnacia, subsequently Membranilarnacia?.
Questionable assignment: Lachkar and Masure in Fauconnier and Masure (2004, p.390) as a problematic species; these authors recommended that the name be restricted to the type material.
Holotype: Cookson and Eisenack, 1982, pl.5, fig.3
Age: Albian-Cenomanian
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Original description: [Cookson and Eisenack, 1982] (translated from German):
Membranilarnacia wetzeli n. sp.
Plate 5, Fig. 3; and? Plate 6, Fig. 16
? 1933 Membranilarnax pterospermoides - O. WETZEL, 1933, p. 52; Plate 6 Figs. 1, 2.
Type: The specimen shown on Plate 5, Fig. 3 and preserved in specimen Balcatta 170/7.
Diagnosis: Central shell spherical, with numerous radial appendages that branch out at the end in a fork-like or anchor-like manner and enclose an almost concentric, delicate outer shell. Their length is less than the radius of the central shell; moreover, they are not of equal length, but are noticeably shorter on one side than the other, with gradual transitions.
Dimensions: Central shell approx. 60 mm, total diameter approx. 90 μ; Length of appendages 10-20 μ. The second specimen has similar dimensions.
Remarks: The species is similar to the flint inclusion Membranilarnax pterospermoides described by O. Wetzel, the type of its genus Membranilarnax. However, since the genus M. was ambiguously defined and had to be abolished because the flint fragment containing the type was lost (EISENACK, 1959, 1963), no clarity can be gained about the structure of M. pterospermoides, and one can only judge from the illustration. I attach no importance to the oval shape of M. pterospermoides, and thus it seems to me that M. wetzeli is identical to M. pterospermoides.
The second specimen is less well preserved, especially with regard to the struts (Plate 6, Fig. 16). In both specimens, the thin outer shell is partially destroyed and folded, especially in the second specimen.
Occurrence: Both specimens from the Balcatta No. 1 borehole; Fig. 3 on Plate 5 at 170 ft. and Fig. 16 on Plate 6 at 180-210 ft., Osborne Formation, Albian-Cenomanian.