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Scytonematopsis

Generic name: SCYTONEMATOPSIS Kiseleva, 1930. Zhurn. Russk. Bot. Obsc. 15: 174.
Synonyms:
SETCHELLIELLA De Toni, 1936. Noter. nom. alg. 8: 6.
TILDENIA Kosinskaja 1926
Diagnosis:
Type species: Scytonematopsis woronichinii Kiseleva 1930.
Descriptions:
Komárek (1992): Filamentous - thallous; solitary branched filaments, clusters with parallely or irregularly arranged filaments or mats on the substrate. Filaments free or densely coiled, creeping on the substrate, or joined to the substrate by middle parts and free ends of branches, sparsely or commonly falsely branched, usually with two (rarely with one) branches. Branching initiates after trichome disintegration by help of necridic cells, rarely after loop-formation, not at heterocytes. Trichomes isopolar, but sometimes (young trichomes) forming Homoeothrix-like heteropolar stages; ends of young trichomes and branches cylindrical with rounded terminal cells, but later always distinctly narrowed and sometimes with elongated, cylindrical, vacuolized apical and subapical cells; trichomes constricted or unconstricted at cross walls. Sheaths firm, limited, hyaline or (usually) parallely lamellated and telescopic, in majority of species yellowish-brown in old specimens. Cells shorter or longer than wide, variable in length, pale or olive-green, rarely pinkish or bright blue-green, towards the ends elongated and vacuolized, always without gas vesicles; numerous necridic cells. Heterocytes develop in dependence on the nitrogen concentration, intercalar, usually solitary, cylindrical or barrel-shaped, of diffe- rent length. Akinetes described only rarely in rows (revision necessary).
Genotype differences, molecular
data:
Reproduction strategies, life cycles, cell division:
Komárek (1992): Cells divide crosswise to the trichome axis. Reproduction by hormogonia, which separate from the filament by help of necridic cells, liberate from the sheath and germinate at both ends.
Ultrastructure:
Taxonomic position, higher hierarchy:
Cyanophyceae, Nostocales, Scytonemataceae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): Periphytic and metaphytic species, five species' are known from tropical re- gions (rice fields, littoral of lakes, springs, swamps), one species is ma- rine, one described from thermal springs (USA), one from the rocky littoral of lakes and submersed stones of the alpine zone of Central European high mountains.
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:

List of species:

Scytonematopsis ambigua Emoto et Hirose 1952
Scytonematopsis calotrichoides Geitler 1933
Scytonematopsis contorta Vaccarino et Johansen 2011. Fottea 11(1): 151
Scytonematopsis crustacea (Thuret ex Bornet et Thuret) Kováčik et Komárek 1988
Scytonematopsis fuliginosa (Tilden) Copeland 1936 [sensu Tilden, non sensu Copeland]
Scytonematopsis ghazipurensis Pandey et Mitra 1972
Scytonematopsis hydnoides Copeland 1936
Scytonematopsis incerta Geitler 1933
Scytonematopsis kashyapii (Bharadwaya) Geitler 1935 
Scytonematopsis neocaledoniense Couté, Tell et Thérézien 1999. Cryptogamie, Algol. 20(4):328
Scytonematopsis pilosa (Harvey ex Bornet et Flahault) Umezaki et M. Watanabe 1994
Scytonematopsis starmachii Kováčik et Komárek 1988
Scytonematopsis variabilis Yoneda
Scytonematopsis woronichinii Kiseleva 1930

Unclear taxa:
Calothrix pulvinata [Mertens 1817] C. Agardh ex Bornet et Flahault 1886
Calothrix vivipara Harvey ex Setchell et Gardner 1919
Scytonematopsis fuliginosa (Tilden) Copeland 1936 [sensu Copeland, non sensu Tilden]
Tildenia dura (Harvey ex Bornet et Flahault) Poljanskij 1928

Keys:
List of stains:
Drawings:
Komárek 1992
Application technology:
Literature:

  2.1 taxonomy: E. Kiseleva 1930, Geitler & Ruttner 1935, Copeland 1936, Geitler 1942, Kováčik & Komárek 1988, Komárek 1992
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: