Oxneriaria immersa H.S.Asghar, R.Zulfiqar & Khalid, 2023

Zulfiqar, Rizwana, Asghar, Hafiza Simab & Khalid, Abdul Nasir, 2023, New species of genus Oxneriaria S. Y. Kondr. & Lőkös (lichenized Ascomycota, Megasporaceae) from Khyber Pakhtunkhwa, Pakistan, Cryptogamie, Mycologie 44 (8), pp. 109-116 : 110-112

Oxneriaria immersa H.S.Asghar, R.Zulfiqar & Khalid , sp. nov.

( Fig. 2 )

Characterized by distinctly elongating/spreading marginal areoles, absence of prothallus, poriform-aspicilioid apothecial discs, larger ascospores (20-25 ×10-15 µm) and the presence of norstictic acid.

HOLOTYPE. — Pakistan. Khyber Pakhtunkhwa Province, Kohistan, Dassu , on calcareous rocks, 841 m a.s.l., 35°35’N, 73°37’E, 12.VII.2020, K. Habib & A.N. Khalid, KH-63 (holo-, LAH [ LAH37898 ]; GenBank[ OQ249532 ]).

PARATYPE. — Pakistan. Khyber Pakhtunkhwa, Swat, Miandam, on calcareous rocks, 1800 m a.s.l., 35°41’N, 72°48’E, 15.IX.2021, M. Usman, RG-15-A (para-, LAH [ LAH 37911]; GenBank[ OQ 152021]).

ETYMOLOGY. — The specific epithet ‘immersa’ (Latin) refers to the immersed apothecial discs.

CHEMISTRY. — K+ (yellow turning red), C–, KC–. TLC: norstictic acid.

HABITAT AND ECOLOGY. — The holotype (LAH37898) was found on calcareous rocks in a dry, temperate area, in an open situation, exposed to sun and rain. The temperature typically varies from –8 to 28°C and the annual rainfall varies between 700 and 800 mm. The topography of the area has extreme variations in elevation. The type specimen was found at an elevation of 841 m a.s.l. whereas the paratype (LAH37911) was found at an elevation of 1800 m a.s.l., in thick hilly forests of Miandam, Swat Valley, with mean maximum and minimum temperature of 30°C and –2°C, respectively.

MYCOBANK. — MB849311.

DESCRIPTION

Thallus crustose-areolate, well-defined, up to 4 cm across, pruinose, 200-400 µm thick in section. Areoles: rounded to irregular, plane to convex, 0.3-1 mm in diameter, marginally elongated/spreading giving a lobate view, up to 1.5 mm long.

Prothallus: absent. Color: dark grey when dry, greenish grey when wet. Upper cortex: dark brown, 10-15 µm thick, cells rounded, 5-9 µm in diameter. Algal layer: 40-70 µm thick, photobiont chlorococcoid, 9-12 µm in diameter. Medulla: 200-250 µm thick, white, hyphae hyaline, 3-4 µm wide. Apothecia: poriform-aspicilioid, 1-3 per areole. Disc: black, smooth, shiny, epruinose, plane to concave, 0.1-0.7 mm in diameter. Margins: indistinct. Epihymenium:brown, 10-15 µm tall. Hymenium: hyaline, 90-100 µm tall. Hypothecium: hyaline, 50-70 µm tall. Asci: hyaline, clavate, 90-130×15-20 µm. Ascospores:hyaline, subglobose to ellipsoid, 20-25 ×10-15 µm.

NOTES

Morphologically Oxneriaria immersa H.S.Asghar, R.Zulfiqar & Khalid , sp. nov. resembles O. virginea (Hue) S.Y.Kondr. & Lőkös but differs in having poriform-aspicilioid apothecial discs (vs poriform or slightly protruding), larger ascospores 20-25×10-15 µm (vs smaller, 14-22 ×9-12 µm) and a different chemistry, i.e., the presence of norstictic acid (vs no substance detected or once only with stictic acid) ( Nordin et al. 2011; Halıcı et al. 2018).

Oxneriaria immersa H.S.Asghar, R.Zulfiqar & Khalid , sp. nov. is also morphologically close to O. kohistaniensis but differs in having a crustose-areolate thallus (vs verrucoseareolate), elongating/radiating marginal areoles (vs non radiating), a smaller hymenium 90-100 µm (vs 100-150 µm), sub-moniliform (vs simple) paraphyses and larger ascospores 20-25 ×10-15 µm (vs smaller, 15-20×9-12µm) ( Zulfiqar et al. 2023). From Oxneriaria permutata (Zahlbr.) S.Y.Kondr. & Lőkös the new taxon differs in having an absence of prothallus (vs presence), a slightly taller hypothecium 50-70 µm (vs 40-50 µm), larger ascospores 20-25 ×10-15 µm (vs smaller, 15-22× 9-12 µm), large conidia 15-35 µm (vs 16-18 µm) and a different chemistry, presence of norstictic acid (vs no substance detected) ( Nimis 2016).

Another, phylogenetically, related taxon is Oxneriaria iqbalii , which has similar thallus coloration and nearly identical size of the ascospores but the new taxon differs in having elongating/radiating marginal areoles (vs non radiating), a smaller hymenium 90-100µm (vs 130-160µm) and the presence of norstictic acid (vs no substance detected) ( Zulfiqar et al. 2023). See also Appendix 1.

Figures

FIG. 2. — Oxneriaria immersa H.S.Asghar, R.Zulfiqar & Khalid, sp. nov. (holotype): A, crustose-areolate thallus; B, apothecia; C, cross section of an apothecium; D, ascospores. Scale bars: A, 1 cm; B, 0.5 mm; C, 50 µm; D, 15 µm.