Pontosphaera wondersii

Pontosphaera wondersii Varol, 2025a

A small species of Pontosphaera, characterised by a narrow, relatively high wall and an extremely thin distal cover over the non-porous proximal plate.

In honour of Dr A. H. Wonders, biostratigrapher/micropaleontologist, Jakarta, Indonesia, in recognition of his contributions to biostratigraphy.

Length = 5.40 μm; Width = 3.23 μm; Height = 1.76 μm (all measured in XPL).

Optical Properties: Pontosphaera wondersii displays a whitish-grey interference colour in the central area, in contrast to the white interference colours of the wall in the plan view in XPL. The apparent angle between the inclined extinction lines is 81°, corresponding to an obliquity angle of 9° on the distal side. This species exhibits length-fast (−) elongation in the plan view. The outer wall displays length-fast (-) whilst the inner wall shows length-slow (+) elongation at the side view (Plate 74, Fig. 16 in Varol, 2025a).

Varol, O. 2025a. A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication. 29: 1-222