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Hormathonema

Generic name: HORMATHONEMA Ercegović, 1929. Arch. Protistenk. 66: 167. [nomen conservandum]
Synonyms:
Diagnosis:
Type species: Hormathonema violaceo-nigrum Ercegović 1930.
Descriptions:
Komárek & Anagnostidis (1998): Thallus mainly epilithic, with irregularly or +/- in rows clustered cells, or pseudofilamentous. Epilithic pseudofuaments are composed of the irregular uni- or multiseriate rows of irregular groups of more or less spherical cells, which are surrounded by their own mucilaginous, sometimes widened and slightly lamellate envelopes; sometimes develop endolithic (boring) pseudofilaments, which grow directly into the limestone substrate and are composed of uniseriate rows of cells which are usually distant from one another, and separated by thick, mucilaginous, usually transversely lamellate and layered sheaths; all pseudofilaments are enveloped by lamellate, gelatinous, wide and delimited sheaths, sometimes coloured, yellowish-brown or violet, sometimes laterally (or pseudodichotomously) divaricate («branched»). «Branches» are lateral and arise after the lengthwise division of cells in pseudofllaments; endolithic pseudofllaments sometimes consisting only of one (-2) terminal cells. Cells spherical, irregular or polygonal, slightly elongate in euendolithic pseudofilaments, usually wider at their ends.
Komárek (1998): Unicellular - colonial; thallus composed from epilithic and endolithic pseudofilaments. Epilithic pseudo filaments form the irregular uni- or mor~ seriate rows or irregular groups of more or less spherical cells, which are enveloped by their own mucilaginous, sometimes widened and slightly lamellated envelopes; endolithic (boring) pseudofilaments grow directly into the limestone substrate and are composed from uniseriate rows of cells which are distant one from another, separated by thick, mucilaginous, usually crosswise lamellated layers; all pseudofilaments are enveloped by lamellated gelatinous, wide sheaths, sometimes coloured, yellowish-brown or violet, sometimes divaricated ("branched"). Cells spherical, irregular or polygonal, slightly elongated in endolithic pseudofilaments, usually more widened at their ends.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek & Anagnostidis (1998): Cells divide irregularly in various planes, in pseudofilaments with predominant crosswise binary fission. After division, they separate soon from one another and produce their own sheaths. Reproduction by solitary cells (monocytes) which are liberated from the mucilaginous sheaths in the upper part of pseudofilaments, or by small gelatinous clusters of several cells. Baeocytes not observed (even not in culture).
Komárek (1998): Cells divide irregularly in different planes, in pseudofilaments with prevailing crosswise binary fission. After division, they separate soon one, from another and produce their own sheaths. Reproduction by solitar cells (monocytes) which liberate from the mucilaginous sheaths, or by small. gelatinous clusters of several cells. Nanocytes not observed.
Ultrastructure:
Taxonomic position, higher hierarchy: Cyanophyceae, Chroococcales, Hydrococcaceae
Notes to taxonomy, misinterpretations:
Komárek & Anagnostidis (1998): The genus Hormathonema was originally described with only one (type) species H. paulocellulare
Ercegović 1929 (later corrected with slightly modified descriptions; Ercegović 1930, 1932). However, this first species corresponds to the previously described genus Solentia Ercegović 1927 (endolithic, with baeocytic reproduction), and the generic name Hormathonema was later commonly used for another type of mostly epilithic cyanoprokaryotes, from which H. violaceo- nigrum and H. luteo-brunneum are the most characteristic members. The, species H. paulocellulare was transferred therefore into the g. Solentia by Le Campion-Alsumard & Golubić (1985b) and Le Campion-Alsumard & al. (1996) (see p. 457), and the generic name Hormathonema was proposed for conservation in the later sense, with the type species H. violaceo-nigrum.
Ecology, ecophysiology, ecological significance:
Komárek (1998): Marine; all species described from Mediterranean Sea; they occur on rocky limestone shores, probably more distributed. The genus must by retypified and the generic name should be conserved in the sense of Ercegović (1930,1932) and, particularly, Le Campion et Golubić (1985).
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:
List of species:
Hormathonema epilithicum Ercegović 1932
Hormathonema longicellulare Ercegović 1932
Hormathonema luteo-brunneum  Ercegović 1930
Hormathonema sphaericum Ercegović 1932
Hormathonema violace-nigrum Ercegović 1930

>Unclear taxa:
Hormathonema dichotoma Chu et Wu 1984 [nomen provisorium]
Hormathonema onychoides Gonzalez-Guerrero 1951
Hormathonema sinensis Chu et Wu 1984 [nomen provisorium]

Synonyms:

Hormathonema paulocellulare Ercegović 1929 = Solentia paulocelularis (Ercegović) Le Campion-Alsumard et Golubić 1985

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

  2.1 taxonomy: Ercegović 1929, Ercegović 1930, Ercegović 1932, Geitler 1932, Fremy 1934, Geitler 1942, Kosinskaja 1948, Le Campion-Alsumard et Golubić 1985, Pantazidou 1991 (diss.), Komárek 1992, Le Campion-Alsumard, Golubić & Pantazidou 1996, Komárek & Anagnostidis 1998
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: