Fungalpedia – Note 173, Namibialina
Namibialina R. Spjut & Sérus.
Citation when using this entry: Shah et al. 2024 (in prep) – Fungalpedia, new genera in 2020.
Classification: Ramalinaceae, Lecanorales, Lecanoromycetidae, Lecanoromycetes, Pezizomycotina, Ascomycota, Fungi
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1.
Namibialina is a lichenized genus introduced by Spjut et al. (2020) with typified by N. melanothrix (≡ Ramalina melanothrix) as a new combination in Ramalinaceae. The phylogenetic position of N. melanothrix can be compared using existing sequences from LSU, SSU, and RPB1. Namibialina is a fruticose genus endemic to southwestern Africa, and exhibits specialized ecology in the coastal deserts. Phylogenetically, Namibialina is sister to Ramalina and diverged from each at around 48 million years ago. The forementioned clade forms a close relationship to Vermilacinia and Niebla which split around 30 million years ago (Spjut et al. 2020) . However, the phylogeny of fruticose genera is still unclear about their ancestral crustose genera.
Namibialina species are typically slow-growing and have a long lifespan. Thallus of Namibialina is shrubby, arising from a single holdfast, rigid or flexuose, growing to a several centimeters when epiphytic or saxicolous or developing terricolous shrubby cushions, typically, pale green or yellowish-green colour (Writh 2010). The main branches are terete-angular or flattened, distinctly canaliculated due to well-developed longitudinal strands of cartilagineous tissue. The branches typically divide, either regularly or not, dichotomous or not, and their apices typically have capillaceous or blackish terminal hairs. Lateral branches and spinules may be present, but typical isidia or soralia have never been observed. The medulla is arachnoid and extremely thin. The cortex is two-layered but may not always exhibit the typical structure. Apothecia may be present or absent, disciform, terminal or marginal, and are perpendicular to the branch in their orientation. The ellipsoid ascospores are either straight or slightly curved, uniseptate. Pycnidia are commonly found with black ostioles. Secondary metabolites: usnic ac. in the cortex (Writh 2010). Two species found in the coastal deserts of South Africa were assigned to Namibialina, including Ramalina angulosa, which was found to be a paraphyletic assemblage of three species, and Ramalina melanothrix, which was found to be a single taxon. As mentioned in the Taxonomy and Nomenclature, the sequence of type material was not available for investigation; hence its nomenclature remains unclear (Spjut et al. 2020). Currently, there is only one species listed in Index Fungorum (2023) under Namibialina.
Type species: Namibialina melanothrix R. Spjut & Sérus
Figure 1 – Namibialina angulosa found in the Skeleton Coast Park rocky of Namibia. a Overview of species and habitat. Photo credit: Emmanuël Sérusiaux.
Reference
Entry by
Sujit Shah, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand.
(Edited by Antonio R. Gomes de Farias & Achala R. Rathnayaka)
Published online 10 January 2024