|Daughter taxa (time control age-window is: 0-800Ma)|
Central-area open; wing merges into flange; blanket confined to central opening
Like H. ampliaperta but with a narow slit-like opening in the central-area.
Large to medium sized, with closed central-area and wide wing which extends along most of length of helicolith.
Like H. magnifica but with open central area, and larger
Distinguishing features: Early Miocene group of Helicosphaera species without a sinlge central opening, blanket confined to central area, variably developed wing.
Farinacci & Howe catalog pages:
Morphology: Early Miocene group of Helicosphaera species without a sinlge central opening, blanket confined to central area, variably developed wing.
|Metrics||Lith size: 7->15µm;|
Last occurrence (top): in mid part of Langhian Stage (49% up, 14.9Ma, in Langhian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Chattian Stage (25% up, 26.8Ma, in Chattian stage). Data source: Total of range of species in this database
Plot of occurrence data:
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