Distinguishing features:
Parent taxon (Oblique wall): Wall formed of crystals with oblique c-axes (Obliquipithonella s.l.)
This taxon: Cysts without external paratabulation, often with double-layered calcareous walls, oyter wall formed of blocky rhomboheda, c-axes oblique to wall.
Taxonomy:
English translation: Cysts without external paratabulation, often with double-layered calcareous walls.
The outer wall are built from blocky to elongated calcite rhombohedra oriented at an angle to the surface. These include the Lower Cretaceous species groups: Pithonella patriciagreeleyae/multistrata (cf. KEUPP 1981: 27 ff.) & Pithonella loeblichi BOLLI 1974 (cf. KEUPP 1981: 58 ff.)
Taxonomic discussion: The generic name Obliquipithonella was very widely used for a long period but it is now accepted among most specialists that the name Pirumella has priority and so should be used (see the Dinoflaj website for more details).
Original diagnosis of Obliquipithonella from Keupp & Mutterlose (1984) Zysten ohne äußere Paratabulation, oft mit doppelschichtigen Kalkwänden. Die Außenwand aus schräg zur Oberfläche orientierten, blockigen bis verlängerten Kalzit-Rhomboedern aufgebaut. Hierzu gehören die unterkretazischen Artengruppen: Pithonella patriciagreeleyae/multistrata
(vgl. KEUPP 1981: 27 ff.) Pithonella loeblichi BOLLI 1974 (vgl. KEUPP 1981: 58 ff.)
Catalog entries: Pirumella [no catalog entry yet]
Distinguishing features:
Parent taxon (Oblique wall): Wall formed of crystals with oblique c-axes (Obliquipithonella s.l.)
This taxon: Cysts without external paratabulation, often with double-layered calcareous walls, oyter wall formed of blocky rhomboheda, c-axes oblique to wall.
Geological Range:
Last occurrence (top): within Zanclean Stage (3.60-5.33Ma, top in Zanclean stage). Data source: Total of range of species in this database
First occurrence (base): within Carnian Stage (228.35-237.00Ma, base in Carnian stage). Data source: Total of range of species in this database
Bolli, H. M. (1974). Jurassic and Cretaceous Calcisphaerulidae from D.S.D.P. Leg 27, eastern Indian Ocean. Initial Reports of the Deep Sea Drilling Project. 27: 843-907. gs V O Bolli, H. M. (1980). Calcisphaerulidae and Calpionellidae from the Upper Jurassic and Lower Cretaceous of D.S.D.P. Hole 416A, Moroccan Basin. Initial Reports of the Deep Sea Drilling Project. 50: 525-543. gs V O Keupp, H. & Mutterlose, J. (1984). Organismen-Verteilung in den D-Beds von Speeton (Unterkreide, England) unter besonderer Berücksichtigung der kalkigen Dinoflagellaten-Zysten. Facies. 10: 153-178. gs Keupp, H. (1981). Die kalkigen Dinoflagellaten-Zysten der borealen Unter-Kreide (Unter-Hauterivium bis Unter-Albium). Facies. 5: 1-190. gsReferences:
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Pirumella compiled by Jeremy R. Young viewed: 8-12-2021
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