Discoaster salisburgensis var. araneus (Bukry, 1971) Bralower & Self-Trail 2016
Taxonomic discussion: PETM excursion taxon. Bralower & Self-Trail (2016) argue that this is better regarded as a sub-species of D. salisburgensis.
Distinguishing features: 7-9 rays. Large to very large, typically asymmetric discoaster with a prominent boss on one side and 7-9 tapering rays that have variable curvature and free length (1/3 to 2/3 of total ray length).
Geological Range: Last occurrence (top): within NP10 zone (54.17-55.86Ma, top in Ypresian stage). Data source: PRB entry to Nannotax First occurrence (base): within NP9 zone (55.86-57.21Ma, base in Thanetian stage). Data source: PRB entry to Nannotax
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Discoaster araneus, synonyms included - Discoaster araneus;
Bralower, T. J. & Self-Trail, J. (2016). Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceangraphic significance. Paleoceanography. 31: 1-17. gs
Bukry, D. (1971a). Discoaster evolutionary trends. Micropaleontology. 17: 43-52. gs
Self-Trail, J. (2011). Paleogene Calcareous Nannofossils of the South Dover Bridge core, Southern Maryland (USA). Journal of Nannoplankton Research. 32(1): 1-28. gsVO
Discoaster araneus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-7-2021