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Spiniferites gracilimembranaceus

Spiniferites gracilimembranaceus Strauss and Lund, 1992

Holotype: Strauss and Lund, 1992, pl.4, fig.9
Paratype: Strauss and Lund, 1992
Locus typicus: Papendorf sand pit, Schleswig-Holstein, Germany
Stratum typicum: Miocene (Langenfeldian)

Original diagnosis: Strauss and Lund, 1992, p.170
A species of Spiniferites with a subspherical, smooth- and thin-walled endocyst and a chagrinate to faintly granulate or perforate periphragm which forms high, very delicate, intergonal more or less indented parasutural membranes. These membranes meet in gonal position to form the broad, two- or three-edged membraneous processes, which are distally slightly expanded to form a more or less extensive platform-like furcation.
Bifid process-terminations are generally reduced, some isolated spines only rarely occur at the upper process margin. Paratabulation as typical for the genus, but often masked by the very high membranes.
Archaeopyle of type P (3"), operculum free.

Original description: Strauss and Lund, 1992, p.170
This Spiniferites-species has characteristically high, smooth to chagrinate or faintly perforate parasutural membranes, which are more or less indented between the processes, but which can also be nearly straight, thus resembling Impagidinium- or Leptodinium crests as well.
The membranes meet at different angles in gonal position, thus forming two- or three-edged Spiniferites-processes, which may be distally more or less expanded to form platform-like furcations. The typical bifid process-endings of Spiniferites are almost completely reduced.
Paratabulation and archaeopyle as typical for the genus, but often difficult to discern because of the high parasutural membranes masking them.
Dimensions: Central body: 24-27 x 29-35 µm. Overall size: 43-50 x 47-55 µm (12 specimens measured).

Affinities:
Strauss and Lund, 1992: Spiniferites membranaceus (Ross.) Sarj. differs from S. gracilimembranaceus in having narrower process stems and typical distal bifid process terminations. A close relationship to the Spiniferites cingulatus-group s. l. and to certain Impagidinium-species is evident, but the characteristic combination of parasutural membranes and process-structure justify the creation of a new species.
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