Diatoms of North AmericaDiatoms of North America
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Compare Neidium amphigomphus

(Ehrenb.) Pfitzer emend. K.Lefebvre and P.B.Ham. 2015

Compare

Neidium sacoense has smaller valves and more cuneate apices.

Neidium fossum has a broader central area and one broad longitudinal canal with associated smaller canals on each side of the valve.

Neidium dilatatum has smaller, more rounded areolae, and larger valves.

Neidium amphigomphus var. obtusum has an elliptical valve outline.

Neidium amphigomphus f. curtum is a species belonging to the genus Luticola and has triundulate valve margins.

Neidium iridis is typically larger, and has a row of irregular depressions on one side of the raphe.

LM scalebar = 10 µm
Neidium amphigomphus LM6 Neidium amphigomphus LM5 Neidium amphigomphus LM4 Neidium amphigomphus LM3 Neidium amphigomphus LM2 Neidium amphigomphus LM1
Length Range
49.9-138.6 µm
Width Range
22-31.7 µm
Striae in 10 µm
15-16

Neidium sacoense

Reimer 1966

Eusacoense Brant1182 98 7 1788 Eusaucoense Ill L 4 40 93 1684 Neidium sacoense LM1 Eusacoense Brant1047B 79 1 1433 Eusacoense Brant1047B 72 3 1310 Eusacoense Brant1182 60 5 1095 Eusacoense Brant1182 46 4 839
Length Range
46.4-98.7 µm
Width Range
18-24 µm
Striae in 10 µm
15-16

Neidium dilatatum

(Ehrenb.) Cleve 1894

Neidium dilatatum 1 L1430 Neidium dilatatum 2 L1428 Neidium dilatatum 3 L1428 Neidium dilatatum 4 L1428 Neidium dilatatum 5 L1428 Neidium dilatatum 6 L1430 Neidium dilatatum 7 L1430
Length Range
154-231 µm
Width Range
40-49 µm
Striae in 10 µm
15-16

Neidium fossum

Lefebvre and P.Ham. 2015

Neidium fossum LM6 Neidium fossum LM5 Neidium fossum LM4 Neidium fossum LM3 Neidium fossum LM2 Neidium fossum LM1
Length Range
66.7-129.7 µm
Width Range
20.1-24.9 µm
Striae in 10 µm
17-18

Neidium iridis

(Ehrenb.) Cleve 1894

Neidium iridis LM4 Neidium iridis LM5 Neidium iridis LM2 Neidium iridis LM3 Neidium iridis LM6 Neidium iridis LM1
Length Range
145-261 µm
Width Range
32-37 µm
Striae in 10 µm
12-13

Also compare to

Neidium amphigomphus var. obtusum

Neidium amphigomphus f. curtum

Wislouc & Poretsky