Cavinula pusio
(Cleve) Lange-Bertalot in Werum and Lange-Bertalot 2004 Category: Symmetrical biraphid
BASIONYM: Navicula pusio Cleve 1895
REPORTED AS: Navicula pusio (Krammer and Lange-Bertalot 1986, p. 195, plate 70, figs. 19-21)
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Loren Bahls - October 2012
Length Range: 18.9-22.8 µm
Width Range: 9.2-10.8 µm
Striae in 10 µm: 30-36 in 10 µm at the valve center, including short striae; a little closer at the apices
Description
Valves are elliptic with wide, rostrate apices. The axial area is very narrow, hardly wider than the raphe. The central area is narrow and rectangular in the apical axis. Raphe branches are pin-shaped and widen gradually from the apices toward the proximal ends, which are distinctly inflated. Distal raphe ends are bent in opposite directions (confirmed under SEM). Striae are radiate throughout. Alternately long and short striae surround the central area. Areolae are round, fine and difficult to resolve in LM.
Original Description
Basionym: Navicula pusio
Author: Cleve 1895
Length Range: 16 µm
Width Range: 7 µm
Striae in 10 µm: 30
Original Description
V. elliptical, with broad rostrate ends. L. 0,016; B. 0,007 mm. Axial area very narrow. Central area small. Striae very fine, about 30 in 0,01 mm. radiate at the ends, in the middle alternately longer and shorter, closer towards the ends. - Pl. II f. 3.
Original Images
Cite This Page:
Bahls, L. (2012). Cavinula pusio. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/cavinula_pusio
Species: Cavinula pusio
Contributor: Loren Bahls
Reviewer: Sarah Spaulding
Image Credit: Loren Bahls
- Valves elliptic
- Apices broadly rostrate
- Central area nearly linear
- Alternate long and short striae surround central area
Cavinula pusio has elliptic valves, greater than 8 µm wide. Apices are broadly rostrate. Alternate long and short striae surround a nearly linear central area.
Compare
Cavinula pusio is distinct, as compared to species currently within the genus. Both C. cocconeiformis and C. scutiformis lack protracted apices and have larger central areas. Cavinula pusio, however, may be confused with Navicula detenta, a species that may belong in Cavinula. Navicula detenta has smaller valves and generally lacks short striae around the central area.
Cavinula cocconeiformis
Cavinula scutiformis
Navicula detenta
Citations
Cleve, P.T. (1895). Synopsis of the Naviculoid Diatoms, Part II. Kongliga Svenska-Vetenskaps Akademiens Handlingar 27(3):1-219.
Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.
Werum, M. and Lange-Bertalot, H. (2004). Diatoms in springs, from Central Europe and elsewhere under the influence of hydrogeology and anthropogenic impages. Iconographia Diatomologica 13: 1-417.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 195012
Autecology Discussion
Cavinula pusio has been collected from five springs and small headwater streams in the northern Rocky Mountains. Krammer & Lange-Bertalot (1986) describe it as an uncommon northern-alpine species in Europe, where it prefers oligotrophic waters with low electrolyte content.