Porina sphaerocephaloides Farkas

Porina sphaerocephaloides Farkas, Lichenologist 19 (1): 54. 1987. Fig. 17 B – F Type. TANZANIA • West Usambara Mts, Mazumbai University Forest reserve, in rocky Sagara Ridge in fragments of mossy forest on Zenkerella grotei leaves at 1820 m alt., 23 Jan. 1985, T. Pócs 8518 / AD (holotype: VBI). Notes. Porina sphaerocephaloides is a common species in tropical Africa (Farkas 1987). It has also been reported from Madagascar by Aptroot (2016). This taxon is represented by 13 examined specimens from northern, southern, and central Madagascar (20270 F, 20272 G, 20272 H, 20274 E, 20275 B, 20277 G, 20279 L, 20279 M, 20279 Q, 20280 D, 25373 B, 25375 G, and 27163 C), which were recovered in the P. sphaerocephala clade. Most specimens match the original description by Farkas (1987), although they exhibit substantially greater variation in ascospore morphology than previously reported. The perithecia, 0.25–0.35 mm (n = 39), matched the reported globose, constricted-at-the-base, rough and unequally thickened, yellow to pale ochraceous yellow perithecia measuring 0.25–0.4 mm (Fig. 17 B). The distinct thalline verrucae, regarded as characteristic of this species, were reduced or absent in some specimens. In contrast to the relatively conserved external morphology, ascospore morphology proved to be highly variable. Although some specimens appeared to have exclusively 7 - septate ascospores, others harboured a minority (ca. 10–20 %) of multi-septate ascospores, ranging from 8 - to 12 - septate, alongside 7 - septate ascospores. Ascospore length, width, and degree of constriction likewise varied considerably among specimens (Fig. 17 E, F). An exceptionally divergent specimen (20279 M) harboured exclusively 13–15 - septate ascospores (Fig. 17 D) and perithecia that appeared slightly more uneven and verrucose (Fig. 17 C) relative to others (Fig. 17 B). Its ascospore measurements were analysed separately from the remaining specimens because they fell well outside the observed range, measuring (63 –) 68–78 (– 90) × (5.3 –) 5.7–6.7 (– 7.6) µm (n = 58). The ascospores of the other examined specimens measured (35 –) 44.5–61.5 (– 75) × (3.7 –) 5–7.9 (– 11) µm (n = 253), broadly matching the reported 7 (– 9) - septate ascospores of 42–60 × 6–9 µm, despite several extreme measurements. Despite this pronounced variation in ascospores morphology, neither phylogeny supported a corresponding species-level subdivision. Both mtSSU and ITS markers recovered P. sphaerocephaloides as a distinct clade with several moderately supported subgroups (Figs 2, 3), but these did not correspond to ascospore morphology or any other consistent phenotypic character. For example, specimen 20272 G clustered with the highly divergent specimen (20279 M) in the mtSSU phylogeny despite producing exclusively 7 - septate ascospores that match the typical size ranges. This taxon showed high photobiont flexibility, associating with four algal haplotypes distributed across two rbc L clades (29: 1, 33: 1, 33: 4, and 33: 5) (Figs 4, 5). Overall, the relatively conserved external morphology, the absence of phylogenetically structured phenotypic variation, and the distinctive morphology originally described for P. sphaerocephaloides support interpreting the examined material as a single morphologically variable lineage. Although no published accessions are currently available for comparison, the distinctive morphology makes confusion with other described species unlikely. These specimens are therefore assigned to P. sphaerocephaloides s. str., pending additional sampling, particularly from type-linked material. Specimens examined. MADAGASCAR – Diego Suarez Prov. • Antsiranana, Region: Diana, District: Diego II, Commune: Joffreville, Forontany: Morafeu, National Park of Montagne d’Ambre, Gîte des Roussettes, mixed open woodland, around house and picnic area, 12°31'37"S, 49°10'18"E, alt. 1068 m, 6 Oct. 2014; Ertz 20270 F (BR, TAN). • ibid., across stream at small dam to dirt road and trail down to Lake Mahasarika, moist but not wet lower montane forest, with tall trees and tree ferns, 12°32'03"S, 49°10'28"E, alt. 1177 m, 7 Oct. 2014; Ertz 20272 G, 20272 H (BR, TAN). • ibid., along trail from summit Olioly to small dam near camp Gîte des Roussettes, through moist montane forest, 12°32'34"S, 49°09'23"E, alt. 1242 m, 8 Oct. 2014; Ertz 20274 E (BR, TAN). • ibid., West of Sambava, Marojejy National Park, Trail from Park entrance to Camp Mantella, rather dense humid evergreen lower montane forest, 14°26'48"S, 49°47'06"E, alt. 360 m, 17 Oct. 2014; Ertz 20275 B (BR, TAN). • ibid., along trail from Camp Mantella to Camp Marojejia, rather dense humid evergreen lower montane forest, 14°26'07"S, 49°46'05"E, alt. ca. 650 m, 18 Oct. 2014; Ertz 20277 G (BR, TAN). • ibid., along trail from Camp Simpona down to Camp Marojejia, rather dense humid montane forest, 14°26'20"S, 49°45'08"E, alt. ca. 1200 m, 23 Oct. 2014; Ertz 20279 L, 20279 M, 20279 Q (BR, TAN). • along trail from Camp Marojejia down to Camp Mantella, rather dense humid evergreen lower montane forest, 14°26'07"S, 49°46'05"E ca. 650 m, 23 Oct. 2014; Ertz 20280 D (BR, TAN). – Toliara Prov. • ca. 25 km Northwest of Fort-Dauphin (Tolagnaro), National Park of Andohahela, South part of parcel 1, ca. 5 km West of the village of Malio, 24°56'07.0"S, 46°44'08.5"E, alt. 680 m elev., dense humid forest, 29 Nov. 2019; Ertz 25373 B, 25375 G (BR, TAN). – Ranomafana National Park • trail along the Vatoharanana river from the Vatoharanana camp, 21°17'08.0"S, 47°26'00.7"E, alt. 1015 m, dense humid forest at medium altitude, 30 Oct. 2022; Ertz 27163 C (BR, TAN).