(Cleve) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella heteropleura var. subrostrata Cleve 1894
REPORTED AS: Cymbella heteropleura var. subrostrata (Patrick & Reimer 1975, p. 38, plate 6, fig. 1)
Contributor: Loren Bahls - August 2012
Length Range: 153-255 µm
Width Range: 39-50 µm
Striae in 10 µm: 8-10 at the valve center, 13-16 at the apices
Valves are broadly lanceolate and slightly to moderately dorsiventral in large and small specimens, respectively. The arched dorsal and ventral margins taper to subtly protracted apices. The axial area is wide and expands gradually along the valve midline from the apices toward a somewhat wider and rounded central area. The raphe is lateral but becomes filiform near the proximal and distal ends. Proximal raphe ends with distinct ventrally deflected “crochet hooks” or “shepherd’s crooks”. Distal raphe fissures are bayonet-shaped and deflected dorsally. Striae are radiate throughout and distinctly punctate. Areolae are very coarse and number 11-15 in 10 µm.
Basionym: Cymbella heteropleura var. subrostrata
Author: Cleve 1894
Length Range: µm
Striae in 10 µm:
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Cymbopleura subrostrata is widely distributed in lakes, ponds, fens and headwater streams in the northern Rocky Mountains of western Montana. Here it prefers cold oligotrophic waters with circumneutral pH (range 6.02-7.90) and low specific conductance (range 22-168 µS/cm).
Kootenai Pond, Glacier National Park, Montana: home of Cymbopleura subrostrata.
Credit/Source: Loren Bahls