Aulacoseira nygaardii
(Camburn) Camburn & Charles 2000 Category: Centric
BASIONYM: Melosira nygaardii Camburn in Camburn & Kingston 1986
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Marina Potapova | Jonathan English - December 2010
Length Range: 4-11 µm
Width Range: 4-19 µm
Striae in 10 µm: 22-31
Description
Frustules are cylindrical and form short chains. The ratio of the mantle height to valve diameter is close to 1. The mantle has straight sides, but the mantle/valve face junction is rounded. The valve face appears slightly convex in LM, but flat in SEM. Rows of pervalvar areolae are straight, parallel to the pervalvar axis, 22-31 in 10 µm, with 30-42 areolae in 10 μm. The height of the collum is approximately1/2-1/3 of the mantle height. The valve face is plain, but with short radial striae at the periphery. The spines are anchor-shaped, narrow, and originate from every second or third costa. The ringleiste is shallow and bell-shaped in cross-section.
Original Description
Basionym: Melosira nygaardii
Author: Camburn in Camburn & Kingston 1986
Length Range: 5-11 µm
Width Range: 4-19 µm
Striae in 10 µm: 20-22
Original Description
Frustules rectangular in girdle view, valves slightly rounded at the mantle. Valve (5.0) 6.9-11.0 μm in diameter. Pervalvar axis variable in length, (4.0) 7.0-17.0 (19.0) μm. Valve mantle contains striae which are parallel to the pervalvar axis, striae 20-22 in 10 μm. Striae are finely punctate, puncta 25-30 in 10 μm. Sulcus well developed. Periphery of valve face ornamented with a narrow (<1.0 μm) band of radiate striae. Striae ca. 30 in 10 μm. The remaining valve face is unornamented. A row of spines occurs around the circumference of the valve face, a spine is located every 2-3 striae. Spines ca. 1.0-1.5 μm in length
Original Images
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.
Cite This Page:
Potapova, M., and English, J. (2010). Aulacoseira nygaardii . In Diatoms of the United States. Retrieved May 19, 2013, from http://westerndiatoms.colorado.edu/taxa/species/aulacoseira_nygaardii
Species: Aulacoseira nygaardii
Contributor: Marina Potapova | Jonathan English
Reviewer: Sam Rushforth
Image Credit: Marina Potapova
- Ratio of mantle height to valve diameter close to or < 1
- Rows of mantle areolae straight
- Valve face appears slightly convex
- Valve face with short radial striae at the periphery
- Spines originate from every second or third costa
Valves are 5-11 µm in diameter, with a mantle height of 4-19 µm. The ratio of the mantle height to valve diameter is close to 1. The valve face appears slightly convex in LM. Rows of pervalvar areolae are straight, 22-31 in 10 µm, with 30-42 areolae in 10 μm. The valve face is plain with short radial striae at the periphery. The spines are anchor-shaped, narrow, and originate from every second or third costa. The ringleiste is shallow and bell-shaped in cross-section.
Compare
Aulacoseira nygardii differs from A. nivaloides by the higher density of striae and areolae on the mantle and by the plain valve face. It differs from A. coroniformis by the absence of areolae on valve face.
Aulacoseira nivaloides
Aulacoseira coroniformis
Pearce & Cremer
Citations
Camburn, K.E. and Charles, D.F. (2000). Diatoms of Low-Alkalinity Lakes in the Northeastern United States. Academy of Natural Sciences of Philadelphia, Special Publication 18, 152 pp.
Camburn, K.E. and Kingston, J.C. (1986). The genus Melosira from soft-water lakes with special reference to northern Michigan, Wisconsin and Minnesota. In: Diatoms and Lake Acidity, J.P. Smol, R.W. Battarbee, R.B. Davis & J. Meriläinen (eds), Dr W. Junk Publishers, Dordrecht. pp. 17-34.
Siver, P.A. and Hamilton, P.B. (2005). A reevaluation of Aulacoseira nygaardii (Camburn) Camburn & D.F. Charles (Bacillariophyceae): based on scanning electron microscopy of type material. Nova Hedwigia 81: 257-265.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 10039