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Nexosispinum hesperus ssp. brevispinosum
Nexosispinum hesperus ssp. brevispinosum Torricelli, 2000, p.262, pl.16, figs.2,4–6.
Holotype: Torricelli, 2000, pl.16, figs.4–5.
Age: Hauterivian.
Original description (Torricelli, 2000)
Holotype: Slide PAT 112-ox, England Finder Coordinate W 54 [ Plate XVI, 4 and 5].
Type locality: Cismon borehole, Belluno Province, Veneto, Italy.
Type stratum: Biancone Formation.
Repository: Palynological slide collection, Stratigraphic Department (STIG) of ENI S.p.A., Agip Division, S. Donato Milanese, Italy.
Etymology: Latin ‘brevis’, short, and ‘spinosum’, in reference to the reduced length of processes.
Diagnosis: A subspecies of Nexosispinum hesperus possessing very short processes, ranging in length between 2 and 4 μm.
Description: Cysts spherical to subspherical, with a thin wall (ca. 0.5 μm) punctate or intraperforate, bearing numerous, short, solid processes which are apparently randomly arranged. The processes are commonly simple, but sometimes anastomose, proximally, medially or distally, with one or two neighbouring processes. Processes tips are acuminate, capitate or briefly bifurcate. The archeopyle is precingular, formed by the loss of two plates (type 2P).
Dimensions: Holotype: central body length=50 μm; width=45 μm; processes length=2–3 μm. Range: central body length=45–50 μm; width=45–55 μm; processes length=2–4 μm. Five specimens measured.
Comparisons: The new subspecies Nexosispinum hesperus brevispinosum differs from N. hesperus subsp. hesperus (Autonym) in possessing very short processes, ranging in length between 2 and 4 μm.
Stratigraphic occurrence: Upper Hauterivian, Lower Cretaceous of southern Alps. This taxon was also found in the sediments of the Monte Soro Flysch, Lower Hauterivian of Sicily, Italy (Torricelli, personal observation). A specimen illustrated by Leereveld, 1995 and Leereveld, 1997
Holotype: Torricelli, 2000, pl.16, figs.4–5.
Age: Hauterivian.
Original description (Torricelli, 2000)
Holotype: Slide PAT 112-ox, England Finder Coordinate W 54 [ Plate XVI, 4 and 5].
Type locality: Cismon borehole, Belluno Province, Veneto, Italy.
Type stratum: Biancone Formation.
Repository: Palynological slide collection, Stratigraphic Department (STIG) of ENI S.p.A., Agip Division, S. Donato Milanese, Italy.
Etymology: Latin ‘brevis’, short, and ‘spinosum’, in reference to the reduced length of processes.
Diagnosis: A subspecies of Nexosispinum hesperus possessing very short processes, ranging in length between 2 and 4 μm.
Description: Cysts spherical to subspherical, with a thin wall (ca. 0.5 μm) punctate or intraperforate, bearing numerous, short, solid processes which are apparently randomly arranged. The processes are commonly simple, but sometimes anastomose, proximally, medially or distally, with one or two neighbouring processes. Processes tips are acuminate, capitate or briefly bifurcate. The archeopyle is precingular, formed by the loss of two plates (type 2P).
Dimensions: Holotype: central body length=50 μm; width=45 μm; processes length=2–3 μm. Range: central body length=45–50 μm; width=45–55 μm; processes length=2–4 μm. Five specimens measured.
Comparisons: The new subspecies Nexosispinum hesperus brevispinosum differs from N. hesperus subsp. hesperus (Autonym) in possessing very short processes, ranging in length between 2 and 4 μm.
Stratigraphic occurrence: Upper Hauterivian, Lower Cretaceous of southern Alps. This taxon was also found in the sediments of the Monte Soro Flysch, Lower Hauterivian of Sicily, Italy (Torricelli, personal observation). A specimen illustrated by Leereveld, 1995 and Leereveld, 1997