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Hystrichokolpoma pseudooceanicum
Hystrichokolpoma "pseudooceanicum" Zevenboom and Santarelli in Zevenboom, 1995, p.137-138, pl.4, figs.2-6. Holotype: Zevenboom, 1995, pl.4, figs.2-3. Name not validly published: considered a manuscript name. Age: mid Early Oligocene-earliest Miocene.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Hystrichokolpoma pseudooceanicum Zevenboom and Santarelli in Zevenboom, 1995, according to Zevenboom and Santarelli in Zevenboom (1995), has smooth endo- and periphragm. The apical archeopyle is circular. The hollow tubular processes are distally closed. There are no cingular or sulcal processes. Size: length 25-35 µm, width 30-33 µm, process length 12-15 µm
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Original description (Zevenboom, 1995)
Manuscript holotype: Sample Le III a 36/1 EF (H36/4), Plate IV, 2-3
Manuscript paratype: Sample Le III a 38/1 , EF (M28/4), Plate IV, 4-6
Etmology: In reference to the similarity of this species to Homotryblium oceanicum Eaton, 1976
Type locality: Lemme section, North Italy.
Type stratum: Rigoroso Formation.
Diagnosis: Hystrichokolpoma pseudooceanica is a small species of Hystrichokolpoma . The endo- and periphragm are smooth. The apical archaeopyle (tA) has a circular outline. The hollow tubular processes are distally closed. The paracingular and parasulcal paraplates are not reflected by processes.
Dimensions: Height: 25(34)35 µm; Width 30 (31)33 µm; Processes 12-15 µm. N=20
Description: A very small species of Hystrichokolpoma with slender distally closed hollow cylindrical processes. The endo- and periphragm are smooth. Between processes endo- and periphragm are closely appressed. There are no parasingular and parasulcal processes preent. The archaeopyle is apical [tA] and has a circular outline. The operculum is free.
Discussion. Hystrichokolpoma pseudooceanica, differs from all other Hystrichokolpoma species by itsvery small size and in the possesion of only one process type (the sulcal and paracingular processes are lacking). It differs from all other Hystrichokolpoma reducata Zevenboom and Santarelli sp. nov., which also lacks parasingular and parasulcal processes. It differs from Homotryblium oceanicum Eaton, 1976 by its archaeopyle formation (apical versus epicystal), its distally closed processes and its smaller size.
Occurences: Italy (this study) and the Netherlands (this study).
Total stratigraphic range: middle Lower Oligocene (Brinkhuis et al., 1992; Santarelli et al., in prep.) through lowermost Miocene (this study).
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Hystrichokolpoma pseudooceanicum Zevenboom and Santarelli in Zevenboom, 1995, according to Zevenboom and Santarelli in Zevenboom (1995), has smooth endo- and periphragm. The apical archeopyle is circular. The hollow tubular processes are distally closed. There are no cingular or sulcal processes. Size: length 25-35 µm, width 30-33 µm, process length 12-15 µm
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Original description (Zevenboom, 1995)
Manuscript holotype: Sample Le III a 36/1 EF (H36/4), Plate IV, 2-3
Manuscript paratype: Sample Le III a 38/1 , EF (M28/4), Plate IV, 4-6
Etmology: In reference to the similarity of this species to Homotryblium oceanicum Eaton, 1976
Type locality: Lemme section, North Italy.
Type stratum: Rigoroso Formation.
Diagnosis: Hystrichokolpoma pseudooceanica is a small species of Hystrichokolpoma . The endo- and periphragm are smooth. The apical archaeopyle (tA) has a circular outline. The hollow tubular processes are distally closed. The paracingular and parasulcal paraplates are not reflected by processes.
Dimensions: Height: 25(34)35 µm; Width 30 (31)33 µm; Processes 12-15 µm. N=20
Description: A very small species of Hystrichokolpoma with slender distally closed hollow cylindrical processes. The endo- and periphragm are smooth. Between processes endo- and periphragm are closely appressed. There are no parasingular and parasulcal processes preent. The archaeopyle is apical [tA] and has a circular outline. The operculum is free.
Discussion. Hystrichokolpoma pseudooceanica, differs from all other Hystrichokolpoma species by itsvery small size and in the possesion of only one process type (the sulcal and paracingular processes are lacking). It differs from all other Hystrichokolpoma reducata Zevenboom and Santarelli sp. nov., which also lacks parasingular and parasulcal processes. It differs from Homotryblium oceanicum Eaton, 1976 by its archaeopyle formation (apical versus epicystal), its distally closed processes and its smaller size.
Occurences: Italy (this study) and the Netherlands (this study).
Total stratigraphic range: middle Lower Oligocene (Brinkhuis et al., 1992; Santarelli et al., in prep.) through lowermost Miocene (this study).