Achnanthidium dolomiticum M.Cantonati & Lange-Bertalot 2006
Publication Details
Achnanthidium dolomiticum M.Cantonati & Lange-Bertalot 2006: 1185, figs 1-3
Published in: Cantonati, M. & Lange-Bertalot, H. (2006). Achnanthidium dolomiticum sp. nov. (Bacillariophyta) from oligotrophic mountain springs and lakes fed by dolomite aquifers (Note). Journal of Phycology 42(6): 1184-1188, 3 figs, 1 table.
Request PDFType Species
The type species (lectotype) of the genus Achnanthidium is Achnanthidium microcephalum Kützing.
Status of Name
This name is of an entity that is currently accepted taxonomically.
Type Information
Type locality: Desedan Spring (N4623895, E01225903, 742 m a.s.l., dolomitii Bellunesi National Park, Southe-eastern Dolomites, Italy); (Cantonati & Lange-Bertalot 2006: 1187) Holotype: M. Cantonati; 7 August 2004; Small cascade spring located about 60 m downward from the Caiada postglacial landslide on the left of the Desedan stream; Diatom collection Museo Tridentino di Scienze Naturali (Trento, Italy; Mouseia Code 43514 (Cantonati & Lange-Bertalot 2006: 1187) Notes: Isotypes. Lange-Bertalot Collection at the Senckenberg Museum (Frankfurt, Germany) Code EU-I 98 Fr-SM and PN Diatom Herbarium (The Academy of Natural Sciences of Philadelphia, USA).
General Environment
This is a freshwater species.
Description
Differential diagnosis compared with A. straubianum: Frustules in girdle view comparatively broad with the raphid valve consistently concave and araphid valve convex, hence distinguished from the genus Psammothidium. Valves elliptic to linear-elliptic, ends broadly rounded, in larger specimens broadly protracted (not straight). Length 5 microns to approximately 12 microns, breadth 2.6- 3.8 microns. Raphid valve: raphe straight, filiform with narrowly spaced central ends (not placed distantly as in A. subexigua). Axial area very narrow, linear. Central area forming a narrow fascia extending over the edge between valve face and mantle (not lacking fascia as in A. straubianum, or fascia broader as in A. subexigua). Striae difficult to resolve, 33-35 in 10 microns (not 30 or less in the proximal part as in several comparable taxa). Rapheless valve: areae as in raphid valves or fascia not developed if smaller specimens are concerned. Striae moderately radial throughout, distally not spaced more densely than proximally (in contrast to several comparable taxa). Areolae externally circular to more or less rectangular, possessing foramina lips (i.e. flaps) facultatively in proximal parts of the valve but becoming transapically elongated near the face margins. Circumferentially arranged single areolae on the valve mantle not interrupted by the fascia. Central ends of the raphe slightly expanded and comparatively more closely spaced. Distal ends straight (not curved), considerably longer than the distal pairs of striae. A. petersenii differs by larger and broader (4-5 microns) valves. Psammothidium abundans differs by more widely spaced striae (maximum 30 in 10 microns) and covex raphid valves.
Habitat
Not restricted to one microhabitat but shows a clear preference for aquatic plants (bryophytes and aquatic vascular plants) as substrates. Carbonate springs and lakes. Freshwater habitats, fed by drainage basins dominated by dolomite lithology with medium mineralization, oligotrophic and affected by seasonal desiccation.
Created: 23 January 2007 by G.M. Guiry.
Last updated: 16 July 2019
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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 16 July 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 10 May 2024
