Cymbopleura crassipunctata

Krammer 2003      Category: Asymmetrical biraphid

Cymbopleura austriaca


Cymbopleura edlundii

LM scalebar = 10 µm = 20 pixels.


Contributor: Loren Bahls - December 2011
Length Range: 111-171 µm
Width Range: 29-37 µm
Striae in 10 µm: 8-13


Valves are broadly lanceolate and somewhat dorsiventral, with subrostrate ends. The axial area is three to four times wider than the raphe. It widens gradually into the central area, which is round to elliptical and one-third to one-half as wide as the valve. The axial and central areas are ornamented with faint spots that are about the same size as areolae, but irregularly arranged. The raphe is broadly lateral, becoming reverse-lateral near the proximal ends and narrower near the distal ends. The distal ends are comma-shaped and deflected toward the dorsal side. The proximal raphe ends terminate in bulbous pores, which lie at the edge of a dark and elliptical central nodule. Striae are radiate throughout and distinctly punctate. Areolae are very coarse and number 10-14 in 10 µm.

Original Description

Author: Krammer 2003
Length Range: 94-127 µm
Width Range: 29-36 µm
Striae in 10 µm: 6.5-9.0 (middle) - 14 (ends)

Original Description

Valves slightly dorsiventral, broadly lanceolate, dorsal and ventral margins tapering to subrostrate ends. Length 94-127 µm, breadth 29-36 µm, maximum length/breadth ratio 3.9. Axial area moderately wide, almost in the median line of the valve. Central area large, 1/3-1/2 the valve breadth, rounded to elliptical, sometimes asymmetrical and then more well-developed dorsally or ventrally. Raphe broadly lateral, narrowing towards the distal ends, appearing reverse-lateral near the proximal ends. Proximal raphe ends bulbous central pores; terminal fissures comma-shaped and dorsally deflected. Striae radiate throughout, very distinctly punctate-lineate. Striae in the middle portion (dorsal) 6.5-9/10 µm, up to 14/10 µm towards the ends, puncta 10-14/10 µm.

Original Images

Cite This Page:
Bahls, L. (2011). Cymbopleura crassipunctata. In Diatoms of the United States. Retrieved April 22, 2018, from

Species: Cymbopleura crassipunctata

Contributor: Loren Bahls

Reviewer: Sarah Spaulding


Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.

Kulikovskiy, M.S., Lange-Bertalot, H., Witkowski, A., Dorofeyuk, N.I. and Genkal, S.I. (2010). Diatom assemblages from Sphagnum bogs of the world. I. Nur bog in northern Mongolia. Bibliotheca Diatomologica 55: 1-326.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Cymbopleura crassipunctata CAS

North American Diatom Ecological Database (NADED)

NADED ID: 47133

Autecology Discussion

Cymbopleura crassipunctata has been found in a small pond in western Montana. Here pH measured 7.57 and specific conductance was 16 µS/cm. The type locality for Cymbopleura crassipunctata is Savona on Kamloops Lake, British Columbia, where the species is reported to occur as a fossil (Krammer 2003). Kulikovskiy et al. (2010) recently reported this taxon from Mongolia.


Skinner Pond #2, Beaverhead County, Montana: home of Cymbopleura crassipunctata.

Credit/Source: Loren Bahls