Nannotax Enabling nannofossil research

Description: Asymmetric 5-rayed variety of D. brouweri. 

Remarks:
Most six rayed species produce asymmetric five rayed specimens, and D. asymmetricus can be found throughout the range of D. brouweri.
However, they are notably more abundant, and more consistently present,
in mid Pliocene sediments. It seems to be an intraspecific variety with
a restricted stratigraphical acme. Both the beginning and the end of
the acme can be used for biostratigraphy (cf. Bukry 1973a, Backman
1986).

Original description: