Trichosarcina, Nichols et Bold, 1965

Darienko, Tatyana & Pröschold, Thomas, 2017, Toward a monograph of non-marine Ulvophyceae using an integrative approach (Molecular phylogeny and systematics of terrestrial Ulvophyceae II.), Phytotaxa 324 (1), pp. 1-41 : 24

The genus Trichosarcina

The genus Trichosarcina was described by Nichols & Bold (1965) from shallow pool in granite rocks at Enchanted Rock and Balanced Rock in Texas. The algae is characterized by initial uniserial filaments become pluriserial with time. The other interesting peculiarity is zoosporogenesis. Only one quadriflagellated zoospore was produced per vegetative cell. Unfortunately, the name T. polymorpha is invalid because the type was not designated, and generic and species were described in one diagnosis (descriptio generico-specifica, Art. 38.5, ICN). Chappell & O‘Kelly (1991) performed the ultrastructural investigation of Pseudoschizomeris mucosa Broady and discovered that this alga belong to the genus Trichosarcina ( T. mucosa (Broady) Chappell et O‘Kelly ). Thompson & Wujek (1996) transferred both species to Filoprotococcus Kufferath with the type species Filoprotococcus enteromorphoides Kufferath , which was originally found in lotic water in Luxembourg. They found this alga in the marshy area near Kansas ( USA) as an epiphyte growing on Tolypella nidifica var. glomerata . The authors highlighted that this alga has some clear differences in comparison to T. polymorpha , which are two times larger in cell size and produce 2–4 zoospores per cell. Unfortunately, no information about the number of flagella was provided. Other differences between both genera are the absence of a pyrenoid in Filoprotococcus .

We studied several isolates, including the authentic strains of Trichosarcina polymorpha and T. mucosa . All strains are morphologically very similar and have almost identical SSU and ITS rDNA sequences, thus belonging to one species. Unfortunately, the genus Trichosarcina has not been validly described, and consequently all later combination are also invalid. For a valid publication of genera and species described according to Art. 38.5, three criteria have to be fulfilled. Whereas the first two criteria have been satisfied (monotypic genus at the time of publication, new species, not no combination), the last about the clear typification has not been clarified in Nichols & Bold (1965). Then on or after 1 st January 1958 of the name of a new taxon of the rank of genus or below is valid only when the type of the name is indicated (Art. 40.1, ICN). Nichols & Bold (1965) investigated this species from two collections (1960 and 1961), but they did not designate any of the two as type. Therefore, this genus and species is invalid. As a consequence, we propose the following new genus.