(Camburn) English & Potapova 2009 Category: Centric
BASIONYM: Melosira distans var. nivaloides Camburn in Camburn & Kingston 1986
SYNONYM(S): Aulacoseira distans var. nivaloides (Camburn) Haworth | Melosira distans var. nivaloides Camburn in Camburn & Kingston
Frustules are cylindrical and form short chains. Valves are 4-11 µm in diameter, with a mantle height of 4-7 µm. The ratio of the mantle height to valve diameter is close to 1. The mantle has straight sides and the valve face is convex or concave. Rows of pervalvar areolae are straight or slightly inclined to the right (dextrorse), 14-22 in 10 µm, with 13-21 areolae in 10 μm. The height of the collum is approximately 1/3 of the mantle height. The valve face is covered by areolae. The spines are pointed and narrow, and originate from every second or third costa. The base of the spines tends to point out away from the valve face before curving upwards to become parallel to the pervalvar axis. The ringleiste is very shallow.
Basionym: Melosira distans var. nivaloides
Author: Camburn in Camburn & Kingston 1986
Length Range: 4-11 µm
Striae in 10 µm: 14-17
Frustules rectangular in girdle view. Valve discshaped and distinctly convex or concave, 4.0-9.0 (11.0) μm in diameter. Valve face punctate. Striae on valve mantle are parallel to the pervalvar axis, striae 14-17 in 10 μm. Each stria composed of (3) 4-7 elongate puncta, puncta 13-15 in 10 μm. A row of spines occurs around the circumference of the valve face, spines 8-10 in 10 μm.
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.
English, J. and Potapova, M. (2009). Aulacoseira pardata sp. nov., A. nivalis comb. nov., A. nivaloides comb. et stat. nov., and their occurrences in Western North America. Proceedings of the Academy of Natural Sciences of Philadelphia 158(1):37-48. 10.1635/053.158.0102
Haworth, E.Y. (1988). Distribution of diatom taxa of the old genus Melosira (now mainly Aulacoseira) in Cumbrian waters. In: Round, F.E. (ed.), 1988, Algae and the aquatic environment. Contributions in honour of J.W.G. Lund. Biopress Ltd., Bristol, pp. 138-167.
Siver, P.A. and Kling, H. (1997). Morphological observations of Aulacoseira using scanning electron microscopy. Can. J. Bot. 75: 1807–1835.