Thalloloma nitidum S. Joshi, Upreti & Hur, 2018

Joshi, Santosh, Upreti, Dalip K., Bawingan, Paulina A. & Hur, Jae-Seoun, 2018, New species in the family Graphidaceae (Ascomycota: Ostropales) from the Philippines, Phytotaxa 345 (2), pp. 152-158 : 153

Thalloloma nitidum S. Joshi, Upreti & Hur spec. nov. ( Fig 1A–C )

Mycobank MB824344

Differs from Thalloloma rubromarginatum in lacking isohypocrelline along lirellae.

Type:— THE PHILIPPINES. Ifugao province: Luzón Island, Banaue, Aparngao, Banaue ethnic village and pine forest resort, alt. 1453 m, 16°56’52.6’’ N, 121°3’18.9’’ E, on bark, January 2015, Paulina A. Bawingan PH 150184 (holotype: KoLRI).

Thallus corticolous, crustose, ecorticate, glossy, tightly adpressed to the substratum, off-white to creamish-white, 100–120 μm thick; photobiont trentepohlioid; medulla white crystalline, partially endoperidermal.

Apothecia lirellate, short to long, stellately or irregularly branched, 1–1.2 × 0.08–0.1 mm; disc exposed, brown to dark brown, sometimes thinly white pruinose; thalline margin, thin, persistent at the base in mature apothecia, up to 100 μm thick; proper exciple indistinct to absent; epihymenium brown, granular, 10–15 μm high; hymenium hyaline, clear (lacking oil-droplets), 100–160 μm high, with thick walled and gelatinous, 4–6 μm thick paraphyses, usually amyloid below epihymenium; subhymenium hyaline, 30–60 μm high; asci clavate, 8-spored, (100–)101−120.4−139.8(–150) × (25−)24.8−27.9–31(–32) μm (n =10), non-amyloid; ascospores ellipsoidal, hyaline, muriform (10–15 transverse septa and 1–2 vertical septa), (30–)37−37.3−37.8(–42) × (10−)10.8−12.6–14.4(–15) μm (n =66), with gelatinous sheath (halonate), amyloid.

Chemistry:— K+ yellow turning red, PD + yellow, C–; norstictic acid associated with traces of stictic, cryptostictic and constictic acids detected by TLC.

Etymology:— The specific epithet reflects the bright and glossy thallus of the new taxon.

Distribution and Ecology:— The new taxon is known only from the type locality at higher elevation in association with Diorygma hieroglyphicum (Pers.) Staiger & Kalb , Graphis dracaenae Vain. , Fissurina insidiosa C. Knight & Mitt. , Myriotrema microporum (Mont.) Hale and Pliariona montagnei (v. d. Bosch) Massal.

Remarks:— The new species is characterized by an ecorticate, shiny, thin, off-white to creamish-white thallus, stellately branched lirellae with wide exposed brown disc, mostly covered by a very thin layer of white pruina, 8-spored asci, distinctly halonate, 30–42 × 10–15 μm, muriform ascospores and the presence of norstictic acid with traces of stictic acid and relatives. Norstictic acid is rare in the genus and hitherto found in two species: Thalloloma rubromarginatum Mercado-Díaz, Lücking & Parnmen and T. ochroleucum Z-F. Jia & Kalb. Thalloloma rubromarginatum resembles new taxon in producing a smooth, shiny off-white thallus, stellately branched lirellae, 8-spored asci producing (sub-)muriform ascospores, but differs in having the dark red pigment isohypocrelline along the lirellae, epruinose disc, and the absence of stictic acid. Further, the ascospores of the former species are comparatively smaller (15–20 × 6–8 μm vs. 30–42 × 10–15 μm in Thalloloma nitidum ) in size ( Mercado-Díaz et al. 2014: 200). Thalloloma ochroleucum also has a white tinged adpressed thallus resembling the new species, but differs in containing transversely septate ascospores ( Jia & Kalb 2014: 114). Thalloloma pontalense Dal-Forno & Eliasaro and T. halonatum Staiger are the two other species which are close to the new species in thallus color and ascospores size, but differ chemically in producing stictic acid and protocetraric acid, respectively ( Staiger 2002: 435; Dal-Forno & Eliasaro 2010: 18).

Additional specimen examined:— THE PHILIPPINES. Ifugao province: Luzón Island, Banaue, Aparngao, Banaue Ethnic village and pine forest resort, alt. 1507 m, 16°56’52.4’’ N, 121°3’19.1’’ E, on bark, January 2015, Paulina A. Bawingan PH 150178 (KoLRI).

Figures

FIGURE 1. Thalloloma nitidum (holotype). A. Habit. B. Section through apothecia. C. Ascus and ascospores. Scales: A = 0.5 mm, B = 100 μm, C = 50 μm.