Reticulofenestra clatrata Muller 1970 [length according to description 8-10 µm].
Notes & discussion: There is much morphological variability within this group, including degree of ellipticity/circularity, size of central area and width of tube cycle. A broad species concept is often applied.
In the Neogene the name R. pseudoumbilicus is used in the virtually same sense and can appear essentially identical.
Isn't here more similarity between R. dictyoda and R. hillae? R. hillae is smaller than R. umbilica.
As I conceptualize it, R. hillae bears the same relationship to R. umbilicus as R. gelida does to R. pseudoumbilicus. I've always chalked them up as probable environmental variants of the same species. I keep doingit because I figure that someday it might mean something, and I don't want to have to go back and split them out later.
R. hillae was described as ranging from 14-20?m, so the same as R. umbilicus. There has been quite some discussion about whether R. hillae and R. umbilica are separate taxa, e.g. see Backman & Hermelin (1986).