(Moore ex Ralfs) Crawford 1988 Category: Centric
BASIONYM: Melosira arenaria Moore ex Ralfs 1843
Contributor: Loren Bahls - July 2012
Diameter: 37-95 µm
Mantle Height: 10-15 µm
Rows of areolae in 10 µm: 20-22
Drum-shaped frustules are heavily silicified and joined by valve faces in long filamentous colonies. Striae on the mantles are perpendicular to the valve faces. Areolae of adjacent striae are offset, producing a diagonal lattice pattern. Valves are of two types: Linking valves connect cells within a colony and separation valves occur at the ends of unbroken filaments. Both linking and separation valves have two complementary forms: a cameo form with ridges and an intaglio form with grooves. The interlocking ridges and grooves of linking valves extend from the valve margin to near the central region, where an irregular pattern of bumps and pits may also be present. The mantle edge on the open end of linking valves has a crenulate appearance and the connection between the valve and valvocopula looks like a zipper. In separation valves, the marginal ridges and grooves extend only a short distance in from the valve margin. Unique tubular processes are present on the mantle, which appear as simple pores that are visible in LM.
Ellerbeckia arenaria is one of only two freshwater species of Ellerbeckia recorded in the United States. The other is E. baileyi, which occurs only as a fossil in Oregon and Washington.
Basionym: Melosira arenaria
Author: Moore ex Ralfs 1843
Rows of areolae in 10 µm:
Crawford, R.M. (1988). A reconsideration of Melosira arenaria and M. teres; resulting in a proposed new genus Ellerbeckia. In Algae and the Aquatic Environment (Round, F.E. editor), Biopress, Bristol. 413-433.
Crawford, R.M. and Sims, P.A. (2007). Ellerbeckia baileyi (H.L. Smith) Crawford & Sims comb. nov. typification and frustule morphology of a rare freshwater fossil diatom. Diatom Research 22: 17-26.
Houk, V. (2003). Atlas of Freshwater Centric Diatoms with a Brief Key and Descriptions. Part I. Melosiraceae, Orthoseiraceae, Paraliaceae and Aulacoseiraceae. Czech Phycology Supplement, Volume 1, Czech Phycological Society, Olomouc.
Kociolek, J.P. and Spaulding, S.A. (2002). Morphological variation, species concepts and classification of an unusual fossil centric diatom (Bacillariophyta) from western North America. Journal of Phycology 38: 821-833.
Krammer, K. and Lange-Bertalot, H. (1991). Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(3): 1-576. Gustav Fisher Verlag, Stuttgart, Germany.
The population of E. arenaria described here was collected on 13 June 2012 at Giant Springs State Park on the Missouri River near Great Falls, Montana. Giant Springs is one of the largest freshwater springs in the world and discharges at a rate of 4.37 cubic meters per second. Water in the springs originates in the Madison limestone formation of the Little Belt Mountains, about 75 miles distant. At the point of discharge, water in the springs measures a constant 12.2 degrees C. The sample containing E. arenaria was collected from rocks and concrete that line the spring pool. On the day of collection, water temperature in the pool measured 14.6 degrees C, pH measured 7.50, and specific conductance measured 580 µS/cm. A common diatom associate in this sample was another robust, colony-forming centric: Melosira undulata.
Live colony of Ellerbeckia arenaria showing cells with numerous discoid plastids. Scale bar = 10 µm.
Credit/Source: Loren Bahls
Giant Springs on the Missouri River near Great Falls, Montana: home of Ellerbeckia arenaria.
Credit/Source: Montana Department of Fish, Wildlife & Parks