Porina rufula Vain.

Porina rufula (Kremp.) Vain., Acta Soc. Fauna Flora fenn. 7 (no. 2): 227. 1890. Fig. 18 C, D Type. MALAYSIA • Sarawak [Borneo]; 1866; Beccari (holotype: M [M 0023867]; isotype: G [G 00293679]). Notes. New record for Mayotte. Porina rufula is a pantropical species and among the most common members of the genus in rainforest understories (Lücking 2008). It has previously been reported in Mauritius by Ertz and Diederich (2022). This taxon is represented by three examined specimens, two from Mayotte (21936 A and 21938 A) and one from Mauritius (23539 D), all of which agree well with the descriptions provided by Lücking (1996, 2008). The 3 - septate ascospores measure (21 –) 22.5–26.5 (– 30) × (3.3 –) 3.6–4.4 (– 4.8) µm (n = 49), matching the reported range of 18–27 (– 31) × 3–5 (– 6) µm. The lens-shaped, cherry-red to orange perithecia measure 0.2–0.3 mm (n = 10), matching the reported morphology and dimensions of 0.15–0.3 (– 0.4) mm. In the mtSSU phylogeny, the examined specimens were recovered within the Phragmopeltheca clade and cluster with both Neotropical and Paleotropical P. rufula accessions, although they show closer affinity to the Paleotropical lineage (Fig. 2). Within this lineage, the two Mayotte specimens (Fig. 18 C) form a distinct subgroup, whereas the Mauritian specimen (Fig. 18 D) clusters with a Japanese accession. Porina rufula exhibits one of the highest levels of intraspecific mtSSU divergences recovered in this study, exceeding that observed for the ITS marker. Both Mayotte specimens showed high specificity and were exclusively associated with algal haplotype 33: 2, whereas the Mauritian specimen was associated with one of the most shared algal haplotypes, 33: 1 (Figs 4, 5). Overall, the close agreement with the published morphology and the phylogenetic placement of these specimens support their confident assignment to P. rufula s. str. under the current species concept, although the marked phylogeographic structure indicates that species boundaries within this complex warrant further investigation. Specimens examined. MAYOTTE – South of Tsararano • trail of Mount Bénara, 12°52'44.0"S, 45°09'37.5"E, alt. 560 m, dense humid hillside forest, 01 Oct. 2017; Ertz 21936 A (BR). • ibid., 12°52'45.2"S, 45°09'39.0"E, alt. 575 m, dense humid hillside forest, 01 Oct. 2017; Ertz 21938 A (BR, MAO). – MAURITIUS – Savanne District • Black River Gorges National Park, along the trail to Mt Cocotte, 20°26'30"S (ca. 200 m), 57°28'16"E (ca. 500 m), 720–750 m, 01 Sep. 2019; Ertz 23539 D and Diederich (BR).