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Compare Achnanthidium minutissimum

(Kütz.) Czarn. 1994

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Achnanthidium minutissimum is distinguished from other monoraphid diatoms by its small size, linear-lanceolate shape, and radiate striae. The breadth of the valve is narrower than both Rossithidium pusillum and Achnanthidium eutrophilum. Rossithidium kreigeri has an asymmetric central area on the raphe valves. Achnanthidium atomus is broader relative to the length. Achnanthidium gracillimum has rostrate ends.

LM scalebar = 10 µm
Achnanthidium minutissimum LM4 Achnanthidium minutissimum LM3 Achnanthidium minutissimum LM7 Achnanthidium minutissimum LM2 Achnanthidium minutissimum LM6 Achnanthidium minutissimum LM1 Achnanthidium minutissimum LM5
Length Range
5.6-20.8 µm
Width Range
1.5-3.3 µm
Striae in 10 µm
25-35

Achnanthidium eutrophilum

(Lange-Bert.) Lange-Bert. 1999

Gs009181 Rl4 Gs009181 R46 Achnanthidium eutrophilum LM2 Gs001021 R25 Achnanthidium eutrophilum LM1 Gs001021 R20 Gs001021 R1
Length Range
5.4-17.8 µm
Width Range
2.1-4.0 µm
Striae in 10 µm
25-35 in the middle of raphe valve

Rossithidium pusillum

(Grunow) Round and Bukht. 1996

Rossithidium pusillum LM6 Rossithidium pusillum LM8 Rossithidium pusillum LM10 Rossithidium pusillum LM2 Rossithidium pusillum LM4 Rossithidium pusillum LM12
Length Range
10–16 µm
Width Range
3.1-4.1 µm
Striae in 10 µm
20-24

Achnanthidium pyrenaicum

(Hust.) H.Kobayasi 1997

Achnanthidium pyrenaicum LM5 Achnanthidium pyrenaicum LM3 Achnanthidium pyrenaicum LM1 Achnanthidium pyrenaicum LM4 Achnanthidium pyrenaicum LM2
Length Range
10–16 µm
Width Range
2.5-4.0 µm
Striae in 10 µm
20-25 in the center, 34-40 at the raphe valve ends; 20-28 in the center, 32-38 at the rapheless valve ends

Achnanthidium atomus

(Hust.) Monnier, Lange-Bert. and Ector 2004

Achnanthidium atomus LM3 Achnanthidium atomus LM2 Achnanthidium atomus LM1 Achnanthidium atomus LM4
Length Range
9.9-21 µm
Width Range
3-3.5 µm
Striae in 10 µm
28-30 in raphe valve, 22-25 in rapheless valve

Rossithidium kriegeri

(Krasske) Bahls 2019

47 Lm1 47 Lm5 47 Lm3 47 Lm4 47 Lm6 47 Lm2 47 Lm7
Length Range
6–21 µm
Width Range
2.1-2.9 µm
Striae in 10 µm
21-23

Achnanthidium gracillimum

(Meister) Lange-Bert. in Krammer and Lange-Bert. 2004

Altergracillima 8 Ed Ahgrac Va000071 1B Ed Achnanthidium gracillimum LM2 Ahgrac Va000071 2A Ed Ahgrac Va000071 2B Ed Achnanthidium gracillimum LM1 Altergracillima 9 Ed
Length Range
12-21 µm
Width Range
3.0-3.7 µm
Striae in 10 µm
21-25 in the center valve, 36-45 at the valve ends