Phyllopsora sabahana Kistenich & Timdal

Kistenich, Sonja, Bendiksby, Mika, Vairappan, Charles S., Weerakoon, Gothamie, Wijesundara, Siril, Wolseley, Patricia A. & Timdal, Einar, 2019, A regional study of the genus Phyllopsora (Ramalinaceae) in Asia and Melanesia, MycoKeys 53, pp. 23-72 : 23

Phyllopsora sabahana Kistenich & Timdal sp. nov. Fig. 9C

Diagnosis.

Differs from P. porphyromelaena in having smaller ascospores and in substitutions in the mtSSU and ITS sequences.

Type.

MALAYSIA, Sabah: Malaysian Borneo, SAFE-project Area, mostly Macaranga dominated secondary forest, 2012, P. Wolseley, H. Thüs & C. Vairappan S.B.oQ.3 (BORH!-holotype) [TLC: argopsin (major), norargopsin (minor); DNA: MK412434 (mtSSU)].

Description.

Thallus effuse, squamulose; squamules medium sized, up to 0.8 mm wide, ascending, elongated, often imbricate, incised to deeply divided, plane to weakly convex; upper side pale green to medium green, glabrous, epruinose; margin concolorous with upper side, often finely pubescent; lacinules common, developing from lobe-tips; upper cortex formed by thick-walled hyphae with cylindrical lumina (type 1), 30-40 µm thick, containing crystals dissolving in K (PD+ orange, K–); medulla containing crystals partly dissolving in K (PD+ orange, K–); prothallus well developed, reddish brown.

Apothecia not common, up to 2 mm diam., rounded to irregular, simple or soon becoming conglomerate, weakly to moderately convex, yellowish brown, more or less immarginate even when young; excipulum pale brown to colourless, K–; hypothecium medium brown, K–; epithecium pale brown to colorless; no crystals in apothecia; ascospores narrowly ellipsoid, simple, 6-8 × 2-2.5 µm (n=20). Conidiomata not seen.

Chemistry.

Argopsin (major), norargopsin (minor). Medulla and upper cortex PD+ orange, K–, C–, KC–.

Distribution.

Malaysia (Borneo).

Etymology.

The specific epithet refers to its occurrence in Sabah, Malaysia.

Remarks.

The species is morphologically and chemically very similar to P. porphyromelaena chemotype 1, and is close to be regarded as a morphologically cryptic species. It may, however, be distinguished in forming smaller ascospores (6-8 × 2-2.5 vs. 8-13 × 2-4 µm). Apothecia are not common in neither species, however, and the measurements are based on only 20 spores from each species (the holotype of P. sabahana and two specimens of P. porphyromelaena from La Réunion). In the phylogenetic tree (Fig. 1), the five accessions of P. sabahana form a strongly supported clade as sister to the Neotropical species P. neotinica , from which it may readily be distinguished in its composition of lichen substances ( P. neotinica contains xanthones). So far, P. sabahana is only known from Borneo.

Additional specimens examined.

MALAYSIA, Sabah: Malaysian Borneo: Maliau Basin, surroundings of Agathis Camp, pristine lowland Dipterocarp forest, 2012, P. Wolseley, H. Thüs & C. Vairappan, C. M089 (BORH) [DNA: MK412441 (mtSSU)]; Danum valley, pristine lowland Dipterocarp forest, 2012, P. Wolseley, H. Thüs & C Vairappan D.8.02.4 (BORH) [DNA: MK412442 (mtSSU)]; Ranau district, Kinabalu park, Tambuyukon trail, Kera camp (loc. T089), 6°12.742'N, 116°43.609'E, 728 m alt., epiphytic, 2014-12-08, A. Paukov 2229 (B) [DNA: MK412455 (mtSSU), MK412498 (ITS)] & 2230 (B) [DNA: MK412453 (mtSSU), MK412496 (ITS)].