Planothidium dubium
(Grunow) Round and Bukhtiyarova 1996 Category: Monoraphid
BASIONYM: Achnanthes lanceolata var. dubia Grunow 1880
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Marina Potapova - August 2011
Length Range: 7-20 µm
Width Range: 4-8.5 µm
Striae in 10 µm: 13-15
Description
Valves are linear-elliptical with rostrate, subrostrate or narrowly subcapitate apices. The raphe valve has a linear axial area and transversely rectangular central area. The rapheless valve has a narrow, linear axial area. The asymmetric central area on the rapheless valve contains a shallow depression on the internal valve surface. The raphe is straight with expanded external proximal endings. The striae are radiate throughout both valves.
Original Description
Basionym: Achnanthes lanceolata var. dubia
Author: Grunow 1880
Length Range: 15-17 µm
Width Range: 7-7.2 µm
Striae in 10 µm: 13-14
Original Description
A. lanceolata var. dubia GRUN. (Achnanthidium delicatulum KG. ex parte?) Steht der vorigen Art sehr nahe, und unterscheidet sich fast nur durch die kurzen, breit lanzettlichen kurz zugespitzten Schaalen, und den etwas schmäleren Pseudostauros der unteren Schaalen. Querstreifen 13-14 in 0,01 mm. Länge 0,015-0,017 mm., Breite 0,007-0,0072 mm. Buchberg in Unterösterreich, Belgien.
Original Images
Cite This Page:
Potapova, M. (2011). Planothidium dubium. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/planothidium_dubium
Species: Planothidium dubium
Contributor: Marina Potapova
Reviewer: Sarah Spaulding
Image Credit: Marina Potapova
- Valves linear-elliptical with variable apices
- Valves 4.0-8.5 μm wide
- Rapheless valve with a shallow depression
- Axial area on rapheless valve narrow linear
Valves are linear-elliptical with rostrate, subrostrate or narrowly subcapitate apices. The raphe valve has a linear axial area and transversely rectangular central area. The rapheless valve has a narrow, linear axial area. The asymmetric central area on the rapheless valve contains a shallow depression on the internal valve surface.
Compare
Planothidium dubium is similar in size and shape to P. rostratum, but differs from it by the absence of the hood on rapheless valve. It differs from P. lanceolatum, which also has a depression on the asymmetric central area of the rapheless valve and by the rostrate to subcapitate valve apices.
Planothidium lanceolatum
Planothidium rostratum
Citations
Cleve, P.T. and Grunow, A. (1880). Beiträge zur Kenntniss der Arctischen Diatomeen. Kongliga Svenska-Vetenskaps Akademiens Handlingar, Vol: 17, Issue: 2, 121 pp., 7 pls.
Round, F. E. and Bukhtiyarova, L. (1996). Four new genera based on Achnanthes (Achnanthidium) together with a re-definition of Achnanthidium. Diatom Research 11: 345-361.
Van Heurck, H. (1881). Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers. pls 31-77.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 155021