Hazenia

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 : 32-33

Hazenia versus Chamaetrichon

The genus Hazenia (with the type species H. mirabilis ) was described by Bold (1958) from a pool at Couchville Pike, Tennessee.This alga is characterized by short, irregularly branched filaments surrounded by mucilage.The cells are short and cylindrical with parietal chloroplasts containing pyrenoids with several starch grains. Asexual reproduction occurs through fragmentation of filaments. Sexual reproduction occurs by biflagellated isogametes. Zygotes with multilayered cell walls were also observed. Skaloud et al. (2013a) described a new species, H. broadyi , from a shallow lake near Anderssen Point in Antarctica. They also proposed a new combination H. basiliensis (previously Pseudendoclonium basiliense ). The genus Chamaetrichon was described by Tupa (1974). The type species C. capsulatum was found on the liverwort, Pallavicia lyelli submerged in a shallow drainage area of Double Lake in Sam Houston National Forest (Texas).

Our study revealed that the authentic strains of these taxa have a similar morphology and are phylogenetically very closely related. However, other strains assigned as Pseudendoclonium basiliense and Chamaetrichon capsulatum are not closely to these strains and were therefore described as new genera below. Unfortunately, the generic name Hazenia and its type species H. mirabilis was described in one diagnosis (descriptio generico-specifica, Art. 38.5, ICN) and no type was designated (Art. 40.1, ICN). The situation of the nomenclatural status is similar to those described above for Trichosarcina . The herbarium specimen of Hazenia deposited at Chicago Natural History Museum of this species was not indicated as type material (IRN 3565921, barcode C0172554F; Fieldmuseum.org). Therefore, this genus and species and all other proposed combinations are invalid. In contrast, the genus Chamaetrichon was validly published by designation of C. capsulatum as type species. As type for this species the culture DDT-8 (= UTEX 1918) was designated, which is not permitted by the ICN, but a dried specimen of DDT-8 was deposited under the number IRN 3566414 (barcode C0500089F) at the Field Museum, Chicago. Therefore, this genus is valid and all taxa of this lineage belong to the genus Chamaetrichon . The necessary taxonomic changes are as follows.

Chamaetrichon Tupa 1974 , Beih. Nova Hedwigia 46: 70–71 (diagnosis latina).

Synonym: Hazenia Bold 1958 , Am. J. Bot. 45: 737–743 (nom. invalid).

Investigated strains: SAG 466-1, SAG 1.87, SAG 18.88, SAG 23.88, SAG 2396, UTEX 1918, ULVO-15 ( Fig. 21 ).

Figures

FIGURE 21. Overview about the morphology of the investigated Chamaetrichon strains grown on MIEB12 medium. A, B. SAG 1.87, general and close view of filaments, with a common mucilage, C. UTEX 1918, filaments with rudimentary branching, surrounded by common mucilage stained with indian ink, D. SAG 23.88, branched filaments, E. ULVO-15, short branched filaments surrounded by mucilage at the edge of the colony, F. SAG 2396, short filaments and packets, surrounded by common matrix.