|
|
||||
|
|
|
|
||
|
|
|
|||
|
|
||||
|
Click on images for larger format |
||||
Name derivation:
|
||||
Classification:
|
||||
|
Nitzschia Hassall 1845 Order Bacillariales;
Family Bacillariaceae Synonym Simonsenia Lange-Bertalog 1979 |
||||
Morphology:
|
||||
|
The cells are usually elongated and in valve
view its outline can vary widely. The valves can be straight to sigmoid and
can lye in either valve or girdle view. In valve
view the center can be slightly swollen with rounded edges at each pole. The
keeled margin on one valve faces the margin of the other cell with no keel
and the keel appears to cross the cell diagonally. Striations are occur
along the valve face of the cell. The cells can be unicellular or form chain
like colonies, sometimes forming within mucilage tubes. |
||||
Similar genera:
|
||||
|
Nitzschia
is similiar to Hantzschia,
but differs in that the frustules of Nitszchia
are square instead of rectangular in girdle view. The keeled margins of a
pair of valves are diagonal to each other instead of being opposite each
other as Hantszchia. Simonsenia was recognized as a separate
genus with morphology midway between Nitzschia and Surirella (Lange-Bertalog 1979), but is not separated in PhycoKey |
||||
Habitat:
|
||||
|
Freshwater
or marine; can be epiphytic on sand or planktonic. Heterotrophic Metabolism: See discussion of
utilization of aromatic plant derivatives such as lignin (Pendergrass et al. 1920).
|
||||
Toxicity:
|
||||
|
Nitzschia navis-varingica has been found to produce domoic acids in
the vicinity of Japan, Philippines, Vietnam and Australia. Mainly in tropical
to subtropical marine waters. |
||||
References:
|
||||
|
Hassall, A.H. 1845.
A history of the British freshwater algae, including descriptions of the Desmideae
and Diatomaceae. With upwards of one hundred
plates, illustrating the various species.... pp. vol 1: [i]-viii,
[i]-402, [ i ,
err.]; vol. 2: p. [i]-24, pl. 1-103 (55 as 'lvi').
London, Edinburgh, Paris & Leipzig:
S. Highley, H. Baillière;
Sunderland & Knox; J.B. Baillière; T.O. Weigel. Lange-Bertalot, H. 1979. Simonsenia, a new genus with morphology intermediate between Nitzschia and Surirella. Bacillaria 2: 127-136. Pendergrass, A., W. R. Roberts, E. C.
Ruck, J. A. Lewis, and A. J. Alverson 2020. The genome of the nonphotosynthetic diatom, Nitzschia
sp.: Insights into the metabolic shift to heterotrophy and the rarity of loss
of photosynthesis in diatoms. Round,
F. E., Crawford, R. M., Mann, D. G. 1990. The Diatoms. Cambridge University
Press. New York, NY. Smith, Gilbert, 1950. The
Fresh-Water ALgaie of the United States. McGraw-Hill Book Company, Inc. New
York, NY. |
||||
