Achnanthidium latecephalum

H.Kobayasi 1997      Category: Monoraphid

Achnanthidium kriegeri


Achnanthidium minutissimum

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - August 2010
Length Range: 10-16 µm
Width Range: 3.5-3.9 µm
Striae in 10 µm: 20-26 in the center valve, 35-40 at the ends


Valves are linear-lanceolate with broadly rostrate or subcapitate ends. The raphe valve is concave and the rapheless valve is convex.Both valves possess a linear axial area, which widens slightly in the middle portion of the valve. No central area is present on either valve. The striae are parallel or very slightly radiate throughout both valves. Striae density on both valves is 20-26 in 10 µm in the middle and 35-40 in 10 µm at the apices. The external openings of the areolae are transapically elongated, appearing as narrow slits. Each stria in the middle part of the valve is composed of 4-5 areolae. Short marginal striae are often present in the middle portion of both valves. The raphe is straight, filiform. The terminal raphe fissures are hooked towards the same side of the valve and are slightly expanded at the ends. Externally, the central raphe ends are teardrop-shaped. Internally, the central raphe ends curve to opposite sides.

Original Description

Author: H.Kobayasi 1997
Length Range: 10-18 µm
Width Range: 4.0-4.5 µm
Striae in 10 µm: 18-20 in center raphe valve, ca 22 in center rapheless valve, ca 34 at the ends

Original Description

Valves linear-lanceolate with broadly capitate or rostrate ends, 10-18 μm long, 4.0-4.5 μm wide. Raphid valve: raphe straight and thread-like with slightly dilated central raphe endings somewhat distant from each other, and gently curved terminal fissures; axial area narrowly lanceolate, transapical striae slightly radiate, alternatively long and short in the middle, 18-20 in 10 μm, almost parallel near the ends, ca 34 in 10 μm; puncta forming striae invisible. Araphid valve: axial area linear lanceolate, transapical striae slightly radiate and occasionally having a short stria inserted in the middle, ca 22 in 10 μm, almost parallel near the ends, ca 34 in 10 μm; puncta forming the striae are invisible.

Original Images

Cite This Page:
Potapova, M. (2010). Achnanthidium latecephalum. In Diatoms of the United States. Retrieved April 25, 2018, from

Species: Achnanthidium latecephalum

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


Kobayasi, H. (1997). Comparative studies among four linear-lanceolate Achnanthidium species (Bacillariophyceae) with curved terminal raphe endings. Nova Hedwigia 65: 147-163.

Ponader, K. and Potapova, M. (2007). Diatoms from the genus Achnanthidium in flowing waters of the Appalachian Mountains (North America): Ecology, distribution and taxonomic notes. Limnologica - Ecology and Management of Inland Waters 37: 227-241 . 10.1016/j.limno.2007.01.004

Rimet, F., Tudesque, L., Peeters, V., Vidal, H. and Ector, L. (2003). Assemblages-types de diatomées benthiques des riviéres non-polluées du bassin Rhône-Méditerranée-Corse (France). Bulletin de la Société des Sciences Naturelles de l’Ouest de la France, 2éme supplément hors série, 272–287.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Achnanthidium latecephalum CAS

North American Diatom Ecological Database (NADED)

NADED ID: 1032

Autecology Discussion