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Spiniferites choanus
Spiniferites choanus Matsuoka and Bujak, 1988
Holotype: Matsuoka and Bujak, 1988, pl.14, fig.3a-b, text-fig.18
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.76
Intermediate ellipsoidal to ovoidal proximochorate cyst. Epicyst slightly conical with a small apical node; hypocyst subspherical, without antapical projection. Cyst wall composed of a finely granulate periphragm and thin smooth endophragm in contact except at the parasutural septa and processes. Processes mostly gonal and rarely sutural; gonal processes with membranous shafts, buccinate and irregularly secate, or sometimes perforated distal extremities which are often recurved; sutural processes membranous, small and simple, mostly with bifid or trifid distal endings. Parsutural septa low but distinctive, and reflecting the paratabulation 4" (?), 0a, 6", 6c, 6""", 1p, 1"""", xs .Paraplate 6" small and triangular; paraplate 1""" much reduced. Paracingulum relatively narrow, less than one-tenth of the cyst length, and displaced by approximately twice of its own width in a laevorotary direction. Parasulcus prominent, including at least two paraplates; anterior and posterior sulcal paraplates, almost straight and slightly widening antapically. Archeopyle simple precingular and formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.77
The cyst body varies from ovoidal to ellipsoidal, with a chagrinate periphragm and smooth endophragm which are adpressed except at the processes and parasutural septa. The processes are relatively short (approximately one-fifth of cyst length), mostly gonal, tapering or tubiform, with membranous stalks and roughly secate or rarely entire distal extremities. Sutural processes are rarely present, simple and oblate distally. The operculum is monoplacoid (3" ) and detached.
Dimensions: Holotype; length of cyst 70 µm, width 54 µm, length of processes 17-18 µm. Range: length of cyst 63-70 µm, width 54-60 µm, length of processes 16-20 µm.
Number of specimens measured; 5.
Thecal affinities: Unknown; possibly related to the modern genus Gonyaulax based on its paratabulation and precingular archeopyle.
Affinities:
Matsuoka and Bujak, 1988, p.77: Spiniferites choanus differs from S. pseudofurcatus (Klumpp) in having an ellipsoidal to ovoidal rather than subspherical central body and shorter membranous processes with roughly secate distal extremities. S. choanus differs from S. adnatus in possessing longer gonal processes with secate distal tips, and in lacking a membranous parasuture.
Holotype: Matsuoka and Bujak, 1988, pl.14, fig.3a-b, text-fig.18
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.76
Intermediate ellipsoidal to ovoidal proximochorate cyst. Epicyst slightly conical with a small apical node; hypocyst subspherical, without antapical projection. Cyst wall composed of a finely granulate periphragm and thin smooth endophragm in contact except at the parasutural septa and processes. Processes mostly gonal and rarely sutural; gonal processes with membranous shafts, buccinate and irregularly secate, or sometimes perforated distal extremities which are often recurved; sutural processes membranous, small and simple, mostly with bifid or trifid distal endings. Parsutural septa low but distinctive, and reflecting the paratabulation 4" (?), 0a, 6", 6c, 6""", 1p, 1"""", xs .Paraplate 6" small and triangular; paraplate 1""" much reduced. Paracingulum relatively narrow, less than one-tenth of the cyst length, and displaced by approximately twice of its own width in a laevorotary direction. Parasulcus prominent, including at least two paraplates; anterior and posterior sulcal paraplates, almost straight and slightly widening antapically. Archeopyle simple precingular and formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.77
The cyst body varies from ovoidal to ellipsoidal, with a chagrinate periphragm and smooth endophragm which are adpressed except at the processes and parasutural septa. The processes are relatively short (approximately one-fifth of cyst length), mostly gonal, tapering or tubiform, with membranous stalks and roughly secate or rarely entire distal extremities. Sutural processes are rarely present, simple and oblate distally. The operculum is monoplacoid (3" ) and detached.
Dimensions: Holotype; length of cyst 70 µm, width 54 µm, length of processes 17-18 µm. Range: length of cyst 63-70 µm, width 54-60 µm, length of processes 16-20 µm.
Number of specimens measured; 5.
Thecal affinities: Unknown; possibly related to the modern genus Gonyaulax based on its paratabulation and precingular archeopyle.
Affinities:
Matsuoka and Bujak, 1988, p.77: Spiniferites choanus differs from S. pseudofurcatus (Klumpp) in having an ellipsoidal to ovoidal rather than subspherical central body and shorter membranous processes with roughly secate distal extremities. S. choanus differs from S. adnatus in possessing longer gonal processes with secate distal tips, and in lacking a membranous parasuture.