Neosergipea
Neosergipea is a genus of lichen-forming fungi in the family Roccellaceae. It has four species, all of which are corticolous, crustose lichens that are found in the tropical forests of Brazil. This genus is related to the genera Dichosporidium, Enterographa, and Erythrodecton. It distinguishes itself through unique morphological characteristics and certain chemical constituents, in particular, its non- ascomata and the presence of a vivid orange anthraquinone compound.
Taxonomy
The type species of the genus, Neosergipea aurata, was found in Areia Branca, Sergipe, during ecological studies on epiphytic crustose lichens. The original name of the genus, Sergipea, was derived from this location. It was later found, however, that this name had been previously used for a genus of fossil pollen, requiring a new name for this lichen genus. As a result, the replacement name Neosergipea was introduced.Neosergipea is a part of the family Roccellaceae and finds its place in the phylogenetic tree close to the genera Dichosporidium and Erythrodecton. The tree reveals that Neosergipea is strongly associated with the genus Enterographa, sharing characteristics such as the presence of an anthraquinone. However, Sergipea differed in several respects from both these genera, particularly by the firm, not thallus, the absence of ascoma, and the ascospore type. An updated phylogenetic analysis including all available mitochondrial DNA sequence data showed Neosergipea as a sister genus to Dichosporidium, with Erythrodecton as the basal genus in the clade. Dichosporidium appeared to include two distinct entities, one with D. nigrocinctum and the other with D. boschianum and D. brunnthaleri.
Description
The thallus of Neosergipea is crustose and closely follows the bark surface. It is dull and pale greenish-grey, very thin, and interspersed with a slightly byssoid. The is approximately 0.1 mm in diameter and is not carbonised. Its is hyaline, and the has pale brown internal pigmentation and external orange crystals. The asci are cylindrical to clavate, measuring 73–89 by 21–27 μm.Neosergipea is recognised by its non- ascomata immersed in – structures that exhibit a bright orange colour due to the presence of an anthraquinone. Its ascospores have between 7 and 9 septa, are narrowly and thick-walled with elongated, and typically have dimensions of 35–40 by 5–6 μm.
The lichen's chemical composition includes lichexanthone in the thallus and an unidentified anthraquinone in the stromata, similar to parietin in terms of its Rf-value and KOH-reaction.