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Spiniferites reductus

Spiniferites reductus Matsuoka and Bujak, 1988

Holotype: Matsuoka and Bujak, 1988, pl.14, fig.4a-b
Paratype: Matsuoka and Bujak, 1988
Locus typicus: Navarin Basin COST No. 1 Well, Navarin Basin, Bering Sea
Stratum typicum: H. campanula Zone; Late Oligocene-Early Miocene

Original diagnosis: Matsuoka and Bujak, 1988, p.82
Intermediate to small subspherical to ovoidal proximochorate cyst. Epi- and hypocyst hemispherical and without projections. Cyst wall comprising a thin and granular periphragm and smooth eodophragm, which are adpressed except at processes and the granular parasutures. Processes gonal and sutural; both types solid, short, conical and membranos at the bases. Gonal processes trifurcate and sutural processes bifurcate distally. Paratabulation reflected by parasutural septa and archeopyle sutures as 4", 0a, 6"", 6c, 6""", 1p, 1"""", xs. Paracingulum delimited by six rectangular paraplates and displaced in a laevorotary direction by approximately its own width; parasulcus represented by low parasutural septa, extending onto the epicyst and almost straight. Archeopyle simple precingular and formed by the loss of paraplate 3".

Original description: Matsuoka and Bujak, 1988, p.82
The central body varies from subspherical to ovoidal with a trapezoidal hypocyst in dorso-ventral view. Apical and antapical horns are absent. The cyst wall consists of a periphragm and endophragm adpressed between processes. The gonal and sutural processes are short, granular and membranous at the base One, two or rarely three sutural process occur between the pre- and postcingular gonal processes. The paracingulum is moderately wide and displaced by approximately one cingular width, and the parasulcus is almost straight. The archeopyle is a simple precingular type formed by the loss of paraplate 3"". Dimensions: Holotype; lenght of cyst body 52 µm, width 43 µm, length of processes up to 10 µm. Range; length of cyst 50-53 µm, width 43-49 µm, length of processes 8-10 µm. Number of specimens measured; 5.
Thecal affinities: Unknown; possibly the cyst of a species of Gonyaulax based on its paratabulation.

Affinities:
Matsuoka and Bujak, 1988, p.83: Spiniferites reductus is similar to Achomosphaera spongiosa in having a granular periphragm, but differs in having parasutures and sutural processes. S. reductus resembles S. nortonensis and S. hexatypicus in having short processes, but differs from S. nortonensis in lacking hollow gonal processes and in possessing a thinner periphragm, and from S. hexatypicus in having a granular periphragm plus gonal and sutural processes with membranous bases. S. reductus resembles S. Ienzii (Reid) in possessing many sutural processes, but is distinguished in having a granular periphragm and shorter processes.
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