Nitzschia angustata has been sometimes placed in Tryblionella. Nitzschia angustata, however, lacks the longitudinal fold of most species in Tryblionella. Nitzschia angustata var. acuta has strongly rostrate apices. Nitzschia angustatula is more narrow (around 4 μm) and shorter in length (13-24 μm). Tryblionella brunoi is larger and more broad (9-13 µm), has a longitudinal undulation and has coarser areolae, 20 in 10 μm. Nitzschia siliqua has capitate apices.

LM scalebar = 10 µm
Nitzschia angustata LM1 Nitzschia angustata LM5 Nitzschia angustata LM7 Nitzschia angustata LM3 Nitzschia angustata LM2 Nitzschia angustata LM11
Length Range
30-88 µm
Width Range
6-7.5 µm
Striae in 10 µm

Tryblionella brunoi

(Lange-Bert.) Cantonati and Lange-Bert. 2017

Tryblionella brunoi LM7 Tryblionella brunoi LM6 Tryblionella brunoi LM5 Tryblionella brunoi LM4 Tryblionella brunoi LM3 Tryblionella brunoi LM2 Tryblionella brunoi LM1
Length Range
50.6-116.3 µm
Width Range
8-10.7 µm
Striae in 10 µm

Also compare to

Nitzschia angustata var. acuta

Grunow in Cleve and Grunow 1880

Nitzschia angustatula

Lange-Bert. 1987

Nitzschia siliqua

R.E.M.Archibald 1966