Planothidium holstii
(Cleve) Lange-Bertalot 1999 Category: Monoraphid
BASIONYM: Achnanthes holstii Cleve 1881
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Megan Otu | Sarah Spaulding - March 2011
Length Range: 18-28 µm
Width Range: 8-10 µm
Striae in 10 µm: 12-16
Description
Valves elliptically lanceolate with slightly rostrate apices. The raphe valve has an off-set “bow tie” shaped to oval central area. The rapheless valve has a large, broad central area, becoming more narrow toward the apices. The raphe is straight with expanded, unilaterally deflected proximal ends. The distal raphe ends are deflected to opposite sides of the valve. The striae are radiate on the raphe valve and slightly radiate on rapheless valve. The striae are multiseriate.
Original Description
Basionym: Achnanthes holstii
Author: Cleve 1881
Length Range: 28 µm
Width Range: 9 µm
Striae in 10 µm: 14
Original Description
Lanceolata, apicibus attenuatis et obtusiusculis. Valva superior striis marginalibus, 14 in 0,01 m.m., nodulo centrali indistincta, linea media indistincta. Valva inferior, linea media distincta, striis radiantibus lin. med attingentibus, circa nodulum centralum abbreviatis. Long. 0,028 m.m. Lat. 0,009 m.m. Loc. Grönland, Kornak. Tab. XVI fig. 6 (valv. sup.), 7 (valv. inf.).
Original Images
Cite This Page:
Otu, M., and Spaulding, S. (2011). Planothidium holstii. In Diatoms of the United States. Retrieved June 19, 2013, from http://westerndiatoms.colorado.edu/taxa/species/planothidium_holstii
Species: Planothidium holstii
Contributor: Megan Otu | Sarah Spaulding
Reviewer: Rex Lowe
Image Credit: Megan Otu, Marina Potapova and Mihaela Enache
- Valves relatively large
- Apices slightly rostrate
- Central area "bow tie" to oval on raphe valve
- Central area large, broad on rapheless valve
Valves are relatively large with slightly rostrate apices. The raphe valve has a distinct central area that is “bow tie” shaped. The rapheless valve has a large, broad central area, becoming more narrow toward the apices. Distal raphe ends are deflected to opposite sides of the valve.
Compare
The size range of P. holstii overlaps with P. apiculatum, but these taxa are distinct in several features. The apices are much more narrow in P. apiculatum. Furthermore, the striae of the raphe valve are more radiate. The rapheless valve of P. holstii lacks a hood, which is present in P. apiculatum.
Planothidium apiculatum
Citations
Cleve, P.T. (1881). Färskvattens-Diatomacéer från Grönland och Argentinska Republiken. Öfversigt af Kongliga Svenska Vetenskaps-Akademiens Förhandlingar, Stockholm 38(10): 3-13.
Cleve, P.T. (1895). Synopsis of the Naviculoid Diatoms, Part II. Kongliga Svenska-Vetenskaps Akademiens Handlingar 27(3):1-219.
Cremer, H. and Wagner, B. (2003). The diatom flora in the ultra-oligotrophic Lake El’gygytgyn, Chukotka. Polar Biology 26 (2): 105-114. 10.1007/s00300-002-0445-0
Lange-Bertalot, H. (1999). Neue Kombinationen von taxa aus Achnanthes Bory (sensu lato). Iconographia Diatomologica 6: 276-289.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 155042