Does someone recognize this species? Found it in a mud sample, collected at the Avon-Heathcote estuary, Christchurch, New Zealand. Length - 9.1 um, breadth - 4.8 um.
Your material is similar to Fallacia tenera showed by Sabbe et al. (1999), subsequently transferred to the genus Pseudofallacia by Liu et al. (2012).
Sabbe et al. (1999). New and little-known Fallacia species (Bacillariophyta) from brackish and marine intertidal sandy sediments in Northwest Europe and North America. Phycologia 38 (1): 8-22.
Liu et al. et al. (2012). Pseudofallacia gen. nov., a new freshwater diatom (Bacillariophyceae) genus based on Navicula occulta Krasske. Phycologia 51 (6): 620-626.
You would need SEM analysis of your material for a sure identification.