Amphora bicapitata, Halamphora normanii, and H. latecostata are larger in size. Halamphora tenerrima is similar in size and shape, but has finer striae (up to 28 in 10 µm). Amphora tenuissima has smaller valves.

LM scalebar = 10 µm
Halamphora subtilis LM2 Halamphora subtilis LM14 Halamphora subtilis LM13 Halamphora subtilis LM5 Halamphora subtilis LM1 Halamphora subtilis LM10 Halamphora subtilis LM17
Length Range
12.7-19.3 µm
Width Range
2.7-3.5 µm
Striae in 10 µm

Amphora bicapitata

M.H.Hohn and Hellerman 1966

Halamphora bicapitata LM3 Halamphora bicapitata LM2 Halamphora bicapitata LM1 Halamphora bicapitata LM7 Halamphora bicapitata LM6 Halamphora bicapitata LM4 Halamphora bicapitata LM5
Length Range
23.9-29 µm
Width Range
5.2-5.5 µm
Striae in 10 µm
20-22 off-center on the dorsal side, 22-23 off-center on ventral side

Halamphora normanii

(Rabenh.) Levkov 2009

Halamphora normanii LM1 Halamphora normanii LM3 Halamphora normanii LM4 Halamphora normanii LM5 Halamphora normanii LM2
Length Range
20-30 µm
Width Range
4.3-5 µm
Striae in 10 µm

Halamphora latecostata

Štěpánek and Kociolek 2013

Halamphora latecostata LM1 Halamphora latecostata LM6 Halamphora latecostata LM5 Halamphora latecostata LM7 Halamphora latecostata LM2 Halamphora latecostata LM3 Halamphora latecostata LM4
Length Range
16-50 µm
Width Range
4.1-7.9 µm
Striae in 10 µm
9-13 at dorsal center; 15-18 at dorsal apices; 19-20 ventral

Also compare to

Halamphora tenerrima

(Aleem and Hust.) Z. Levkov

Amphora tenuissima