Krogia borneensis Kistenich & Timdal

Kistenich, Sonja, Rikkinen, Jouko K., Thues, Holger, Vairappan, Charles S., Wolseley, Patricia A. & Timdal, Einar, 2018, Three new species of Krogia (Ramalinaceae, lichenised Ascomycota) from the Paleotropics, MycoKeys 40, pp. 69-88 : 74-75

Krogia borneensis Kistenich & Timdal sp. nov. Fig. 2

Diagnosis.

The species differs from K. isidiata in forming lacinules as vegetative dispersal units, not isidia, and from the other species in the genus in producing sekikaic and homosekikaic acid.

Type.

Malaysia, Borneo, Sabah, Maliau conservation area, trail between Nepenthes Camp and waterfall Takob Akob, 4°43.4'N, 116°52.2'E, 900-1000 m alt., in low (few metres) and open pristine montane "Kerangas" (heath) forest with higher trees mostly along a small stream, on smooth barked tree in the vicinity of the stream, 2013-02-23, C. Vairappan & H. Thüs L291 (BORH, holotype) [TLC: sekikaic and homosekikaic acid; GenBank: MH174275 (mtSSU)].

Description.

Thallus effuse, squamulose; squamules up to 1 mm wide, deeply divided into 0.1-0.2 wide lobes, ascending, imbricate, flattened, elongated to partly linear, often slightly laterally constricted, greyish-green with patches of red (K+ purple) spots, epruinose, glabrous; margin concolorous with upper side, not fibrillose; lower side white; lacinules formed by tips of the lobes. Upper cortex composed of a single layer of thick-walled cells with angular to shortly cylindrical lumina (resembling Eschatogonia -type), not containing crystals (polarised light!); algal layer 30-40 µm thick, filled with crystals dissolving in K; medulla composed of loosely interwoven hyphae, not containing crystals dissolving in K; lower cortex resembling upper cortex, both continuing over the edge of the squamule; prothallus brownish-black, often well developed. Apothecia (present in the holotype only) up to 0.6 mm diam. when simple, forming aggregates up to 1.5 mm diam., medium brown with red patches or entirely reddish-brown, more or less plane, with an indistinct, slightly paler, often flexuose margin; excipulum pale brown to colourless, composed of radiating, closely conglutinated hyphae, in inner part containing colourless crystals dissolving in K; hypothecium partly to entirely stained by a blood red pigment which dissolves in K with a purple effusion; epithecium colourless, not containing crystals. Ascospores filiform, curved, non-septate, spirally arranged in ascus, 20-31 × ca. 1.0 µm (n=10, from holotype). Conidiomata not seen.

Chemistry.

Sekikaic acid (major), homosekikaic acid (major). Spot tests: all negative, except for red patches being K+ purple.

Distribution.

The species is known from five localities in Borneo.

Ecology. The species occurred in rather low "Kerangas" (heath) forest vegetation or on transition vegetation between the heath and oak/conifer (particularly Agathis ) forest at higher elevations (ca. 1000 m) on very poor soils on sandstone (Fig. 2B). The species always grew on the rather smooth barked, middle-sized trees together with various Pyrenulaceae and Graphidaceae .

Etymology.

The specific epithet refers to its occurrence in Borneo.

Remarks.

The medium-sized, flattened squamules make the species morphologically most similar to the neotropical K. antillarum . The squamules are more elongated, often linear and with more lateral constrictions in K. borneensis than in K. antillarum , which has more fan-shaped squamules. The former species has a thin, unicellular cortex on both upper and lower side, whereas the latter has a multicellular (20-30 µm thick) upper cortex and lacks a lower cortex ( Timdal 2009). Chemically, the latter species differs in forming 4-O-methylcryptochlorophaeic acid.

Krogia isidiata shares the secondary chemistry (sekikaic and homosekikaic acid) with K. borneensis , but they differ in their vegetative dispersal units, the former producing cylindrical isidia, the latter flat lacinules (fragmenting squamules). The upper cortex of K. isidiata is multicellular (15-30 µm thick) and the lower cortex is absent.

Additional specimens examined.

Malaysia, Borneo. Sabah: Danum, plot 88, dipterocarp forest logged in 1988, 4°58'N, 117°50'E, 131 m alt., 1997-04-30, P. Wolseley Q21 p.p. (BM 001104020); Danum valley, pristine lowland dipterocarp forest 4°57.96'N, 117°47.32'E, 200-400 m alt., 2012, P. Wolseley, H. Thüs & C. Vairappan D-3-10-2 (BORH); Maliau conservation area, trail between Nepenthes Camp and waterfall Takob Akob, transition between pristine montane "Kerangas" (heath forest) and montane oak-conifer ( Agathis ) forest, 4°42.6'N, 116°52.5'E, 900-1000 m alt., 2013, C. Vairappan & H. Thüs L229 (BM); Ranau district, Kinabalu park, Musang camp on the Tambuyukon trail (loc. T98), 6°12.720'N, 116°40.891' E, 1429 m alt., epiphytic, 2014-12-09, A. Paukov 2234 (B).