Halofilum ramosum Darienko et Pröschold, 2017

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 : 20

Halofilum ramosum Darienko et Pröschold sp. nov. ( Fig. 11D–G )

Diagnosis: Filaments are relative long, consisting of 20–100 cells, richly branched and curved. The cells of primary branches are slightly shorter, equal to or to twice as long as broad; cylindrical or square; 7.8–12.5 μm long × 6.9–8.5 μm wide. The secondary branches appear laterally or bilateral. The terminal cells of secondary branches are cylindrical, often pointed, up to 5 times longer as broad. Cells are 16.0–28.0 μm long × 5.6–7.2 μm wide. The longest terminal cells very often contain 2–3 pyrenoids and nuclei. Such cells probably represent some special stage of vegetative dividing. In the primary filaments, irregular cells containing up to 4 pyrenoids were observed. The cells later formed package-like structures, and from these cells the secondary branches often arise. Reproduction by budding or by zoospores was not observed.

Differs from other species by SSU-ITS sequences and the absence of reproduction by budding.

Habitat: marine, photobiont of Wahlenbergiella striatula .

Type locality: Wales, Anglesey (Ynys Mon), Porth Trecastel, in stone cracks of coastal rocks.

Holotype (designated herein): The strain SAG 2050 is permanently cryopreserved in a metabolically inactive state (cryopreserved in liquid nitrogen) in the SAG, University of Göttingen , Germany.

Iconotype (designated herein in support of the holotype): Fig. 11F in this study.

ITS-2 DNA Barcode: HAL 3a/b in Figs S2.

Comment: This species is probably widely distributed as photobiont and free-living. Additional strains: SAG 2235 and ULVO-28 were isolated from Verrucaria maura, Roscoff , Brittany, France and ULVO-19 was isolated from a green crust on the wall of ruins in Carthage, Tunisia (see Hoffmann & Darienko 2010).

Note: The budding-like reproduction of Halofilum is quite rare among microalgae and has only been reported for few green algal genera, which belong to the Trebouxiophyceae ( Pseudomarvania, Eliaš & Neustupa 2009 ; Marvania , Nannochloris, Yamamoto et al. 2007 ).

Figures

FIGURE 11. Morphology of A–C. Halofilum helgolandicum SAG 2.95 and D–G. H. ramosum SAG 2050 grown on 1/2SWES medium.