Circinaria semicontorta R. Zulfiqar, H.S. Asghar, K. Habib & Khalid

Zulfiqar, Rizwana, Habib, Kamran, Asghar, Hafiza Simab, Wahab, Hira, Sohrabi, Mohammad, Paukov, Alexander G., Ren, Qiang & Khalid, Abdul Nasir, 2024, A new species in the genus Circinaria (Lichenized Ascomycetes: Megasporaceae) from Pakistan, Phytotaxa 652 (2), pp. 124-132 : 127-130

Circinaria semicontorta R. Zulfiqar, H.S. Asghar, K. Habib & Khalid sp. nov. MycoBank No.: MB849956

Circinaria semicontorta has a whitish areolate to subverrucose thallus with a thinning, cracked margin, it has areoles with raised whitish pseudocyphellae containing black ostioles of conidiomata, with 12–25 μm long pycnoconidia, and it lacks of secondary metabolites.

Type:— PAKISTAN. Khyber Pakhtunkhwa Province, Kohistan: Dassu , on calcareous rocks, 841 m a.s.l, 35 o 59ʹ N 73 o 61ʹ E, 9 Jul 2020, K. Habib & A.N. Khalid KH-20 (Holotype LAH38220 ).

( Figure 2 )

Thallus crustose, areolate to sub-verrucose, discrete, c. 10 cm across, 200–300 µm thick in section with a thinning radially cracked marginal part. Areoles contiguous, rarely discrete, irregular, or angular to rounded, weakly concave to plane and convex, pruinose, 0.5–1.2 mm wide, marginally elongated, giving a lobate view, wrinkled (resembling tree branches), up to 1.5 mm long. Prothallus absent. Pseudocyphellae present, indistinctly papilliform, whitish. Thallus color whitish-grey when dry, greenish grey when wet. Upper cortex paraplectenchymatous, 20–30 µm thick, cells rounded, 4–8 µm in diameter. Algal layer even, continuous, 50–60 µm thick, photobiont chlorococcoid, 6–12 µm in diameter. Medulla prosoplectenchymatous, 100–190 µm thick, hyphae white, 2–3 µm wide.

Apothecia aspiciloid, common, 1–2 per areole. Disc black, pruinose, plane to weakly concave, rounded to rarely elongated, 0.2–0.7 mm in diameter. Margins rarely prominent, often forming a whitish rim. Proper exciple indistinct. Thalline exciple 90–100 µm thick. Paraphyses moniliform, apically branched, up to 3 µm wide at the apex. Epihymenium light brown, 15–25 µm tall. Hymenium hyaline, 90–160 µm tall. Hypothecium hyaline, 30–50 µm tall. Asci clavate, hyaline, 70–100 × 15–20 µm. Ascospores 4 per ascus, simple, hyaline, spherical to broadly ellipsoid, 17–25 × 15–20 µm, uniseriate.

Pycnidia immersed in pseudocyphellae, single or sometimes aggregated, punctiform, with black ostiole surrounded by a whitish margin. Conidia simple, hyaline, bacilliform, straight, 12–25 μm × c. 1 μm.

Chemistry: cortex and medulla, all negative. TLC: no substance detected.

Etymology: The species epithet reflects the close relationships with the morphological similar areoles of the crustose species Circinaria contorta .

Distribution and habitat: Circinaria semicontorta (Holotype, KH-20) is a saxicolous species growing on calcareous rocks in a dry temperate climate, at an altitude of 841 m a.s.l., in an open habitat exposed to sun and rain, with a temperature ranging from -8°C to 28°C and rainfall ranging between 700–800 mm annually. Some of the paratypes cited below (KH-210, KH-201) were found growing on silicate rocks in similar habitat as the holotype, but at an altitude of 1,811 m a.s.l. Whereas, other paratypes cited below (HM-10, KSH-17, SL-07) were found growing on silicate rocks in relatively cold climate, at an altitude of 1,598 to 2,300 m a.s.l, with an average annual rainfall varying between 1000–1650 mm.

Notes: Because of its whitish grey colour Circinaria semicontorta sp. nov. is similar to C. thorstenii . The new species differs by its zonate, thinning and cracked thallus periphery, its olive colour (at least when wet), the convex areoles, and the longer conidia. Convex rounded areoles of C. semicontorta sp. nov. may resemble C. contorta . The new species, however, has more closely appressed and thus flattened areoles, longer conidia and, most conspicuously, pseusocyphellae with carbonized ostioles of conidiomata.

Despite their current phylogenetic position within crustose Circinaria , C. semicontorta sp. nov. and C. thorstenii possess characters distinct from other species of this group. Like some vagrant and dwarf-fruticose species they develop pseudocyphellae which usually contain conidiomata and lack aspicilin, which is present in the most of the aforementioned crustose taxa. An important diagnostic character are also the much longer conidia, which are 11–15 μm in Circinaria thorstenii , but 12–25 μm in C. semicontorta sp. nov. The size of conidia in other crustose species in the basal groups of Circinaria falls within the range of 4–11 μm. These characters may indicate closer relationships of these two species with vagrant representatives of Circinaria and imply the necessity of using the multi-locus phylogeny to reveal their position in the tree of the genus.

Additional specimens examined (paratypes): PAKISTAN. Khyber Pakhtunkhwa, Kohistan: Razika Seo Valley , on siliceous rocks, 1,811 m a.s.l., 35 o 26ʹN 73 o 27ʹE, 9 Sep. 2020, K. Habib & A.N. Khalid KH-210 ( LAH38221 ), KH-201 ( LAH38219 ) ; Azad Jammu & Kashmir: Neelam Valley, Kel , 34°50' N 74°22' E, 2200 m a.s.l, on siliceous rocks, July 21, 2019, A. N. Khalid and K. Habib, KSH-17, ( LAH36686 ) ; Swat District, Kalam valley : 35°53' N 72°49' E; 2,001 m a.s.l, on siliceous rocks, 29 August 2020, A.N. Khalid, S. Asghar & K. Habib SL-07 ; District Malakand, Heryankot , 34°50' N 71°90' E; on siliceous rocks, 1,598 m a. s. l., June 15, 2019, HM-10, Hira Wahab, (Bot-20171).

Figures

FIGURE 2. (A–F): Circinaria semicontorta (Holotype). A. Dry thallus B. Apothecia and areoles (dry thallus) C & D. Pycnidia in pseudocyphellae (wet). E. Section of apothecia F. Conidia. Scales: A = 2 cm, B = 0.5 mm, C = 1 mm; D = 1 mm; E = 100 µm, F = 15 µm.