Nannotax3 - ntax_mesozoic - Eiffellithus collis

Distinguishing features: Like E. parvus but larger and with longer cross-arms. Medium sized, with blunt terminations to the cross-arms.

Citation: Eiffellithus collis Hoffmann, 1970

Taxonomic discussion: This taxon is used by Perch-Nielsen (1985), Watkins & Bergen (2003) and Shamrock & Watkins (2009). They do not provide explicit species descriptions but the following comments makes their species concepts reasonably clear:

Perch-Nielsen (1985) in her table (fig.34) separates E. collis from E. turriseiffelii by having blunt terminations to the cross as opposed to pointed ones in E. turriseiffelii.
Watkins & Bergen (2003, p.234) state "The final species of this lineage [equibramus-pavus-collis] is E. collis, which apparently evolved from E. parvus by a significant increase in size and elongation of the trapezohedral cross arms (Plate 3, figs. 7-8)".
Shamrock & Watkins (2009 p.1096) state that "Eiffellithus casulus [i.e. E. turriseiffelii] can be distinguished from the similar sized E. collis by the blunt, rectangular shape of the central cross in the latter when compared to the pointed, diagonal cross of E. casulus. Eiffellithus collis is also markedly elongate."

Distinguishing features: Like E. parvus but larger and with longer cross-arms. Medium sized, with blunt terminations to the cross-arms.

Most likely ancestor: Eiffellithus parvus - at confidence level 3 (out of 5). Data source: Watkins & Bergen 2003.

Geological Range:
Notes: Persists through the Late Cretaceous according Shamrock & Watkins (2009)
Last occurrence (top): within Late Albian Substage (100.50-107.59Ma, top in Albian stage). Data source: original description
First occurrence (base): within BC26 zone (103.27-104.06Ma, base in Albian stage). Data source: original description

References:

Hoffmann, N. (1970c). Taxonomische Untersuchungen an Coccolithen aus der Kreide Norddeutchlands anhand elektronenmikroskopischer Aufnamen. Hercynia. 7(1-3): 163-198. gs V O

Shamrock, J. L. & Watkins, D. K. (2009). Evolution of the Cretaceous calcareous nannofossil genus Eiffellithus and its biostratigraphic significance. Cretaceous Research. 30(5): 1083-1102. gs

Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs V O

Watkins, D. K. & Bergen, J. A. (2003). Late Albian adaptive radiation in the calcareous nannofossil genus Eiffelithus. Micropaleontology. 49(3): 231-252. gs

Tags	LITHS: murolith, elliptical, CA: ca_disjunct, plate, process, diagonal cross, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
Metrics	Lith size: 0->0µm;

Eiffellithus collis

References:

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