Sticta macrolobata Ossowska, B. Moncada, Luecking & Kukwa, 2024

Ossowska, Emilia Anna, Moncada, Bibiana, Luecking, Robert, Flakus, Adam, Rodriguez-Flakus, Pamela, Olszewska, Sandra & Kukwa, Martin, 2024, Additional new species and new records of the genus Sticta (lichenised Ascomycota, lobarioid Peltigeraceae) from Bolivia, MycoKeys 105, pp. 21-47 : 21

Sticta macrolobata Ossowska, B. Moncada, Luecking & Kukwa sp. nov.

Fig. 3

Diagnosis.

Differing from S. laciniata in cyanobacteria as photobiont, thallus up to 25 cm in diam., broad lobes, verrucous (rarely weakly crenate) to tomentose apothecial margins, which is often ciliate in the lower part, light to dark brown lower surface and cyphellae with elevated margins.

Type.

Bolivia. Dept. Santa Cruz; Prov. Florida, Parque Nacional Amboró, above la Yunga Village, senda Los Helechos , 18°03'30"S, 63°54'36"W, elev. 2330 m, Yungas cloud forest, corticolous, 07 June 2011, M. Kukwa 9801 (holotype UGDA, isotype LPB) .

Description.

Primary photobiont cyanobacterial ( Nostoc ). Stipe absent. Thallus irregular, coriaceous, up to 25 cm diam., moderately branched, with 4-5 branches per 5 cm radius, branching pleurotomous to polytomous; lobes laciniate to flabellate, plane, with their apices orbicular and involute, margins entire, not thickened, with brown marginal line; lobe internodes 7-14 mm long, 7-50 mm broad. Upper surface smooth to shallowly scrobiculate, light brown to brown with darker apices when dry, shiny; surface glabrous, without papillae and pruina, but with irregular, scattered, pale beige maculae; marginal cilia absent, but extensions of the lower tomentum visible. Apothecia abundant to sparse, principally laminal to submarginal, dispersed to aggregated, pedicellate, with pronounced invagination on the lower side, up to 5 mm diam.; disc plane, brown to chestnut-brown, shiny, epruinose to delicately pruinose; margin persistent, verrucous to tomentose, rarely weakly crenate, often ciliate in the lower part, with brown tomentum, abundant in young apothecia, sparse in old ones. Vegetative propagules absent. Lower surface plane to uneven, light towards the margins and dark brown towards the centre; primary tomentum dense, thick, but thinner towards the margin, spongy to fasciculate, golden-brown in young parts to brown in older with lighter tips; secondary tomentum present, pubescent. Rhizines present, irregularly dispersed, fasciculate to barbate, up to 6 mm, dark brown. Cyphellae 1-20 per cm2 towards the thallus centre and 41-60 per cm2 towards the margin, scattered, rounded to irregular, urceolate with wide pore, erumpent to sessile, remaining below the level of the primary tomentum, with the margin elevated and involute, brown-coloured, without tomentum or with tomentum at the base; pore (0.25-)0.5-1(-1.5) mm diam.; basal membrane scabrid, yellow. Medulla compact, yellow. Pycnidia present, sparse, immersed.

Upper cortex paraplectenchymatous, 30-40 μm thick, differentiated into two cellular layers with the upper layer consisting of 1-2 layers of small cells, cells 4-15 × 4-10 μm diam., their walls 1-3 μm thick and their lumina rounded to isodiametric, 3-14 μm diam. Photobiont layer 45-75 μm thick, its cells 10-20 μm diam. Medulla 80-120 μm thick, its hyphae 3-4 μm broad. Lower cortex paraplectenchymatous, 30-40 μm thick, homogeneous, consisting of 2-3 layers of cells, cells 7-15 × 6-10 μm, their walls 2-4 μm thick. Hairs of lower primary tomentum up to 220 μm long, in fascicles of more than 20, hyphae simple or rarely branched, 6-8 μm wide with uneven walls, septate with free apices; secondary tomentum sparse, locally developed, up to 2 cells and up to 10 μm long. Cyphellae cavity up to 250 μm deep; cells of basal membrane without papillae. Apothecia biatorine, up to 1 mm high, with distinct stipe; excipulum up to 150 μm broad, laterally with projecting hairs. Hymenium up to 125 μm high; epihymenium up to 10 μm high, brown-orange, with gelatinous upper layer, covered by tiny granules. Asci 6-8-spored, ascospores fusiform, 1(-3)-septate, 25-38 × 6-8 μm.

Secondary chemistry.

Unidentified substance in Rf classes A2-3 and C2. Basal membrane of cyphellae K- to K+ pale yellow, C-, KC-, P-. Medulla K+ ochraceous-yellow, C-, KC-, P-.

Habitat and distribution.

Sticta macrolobata was found on tree bark in Yungas forest. It was collected from a single locality in the Parque Nacional Amboró in the Santa Cruz Department.

Etymology.

The name refers to the presence of wide lobes, which are up to 50 mm broad.

Notes.

Sticta macrolobata resembles S. laciniata , but the latter has green photobiont and the thallus is smaller, up to 10 cm broad and more branched than in the new species ( Hooker 1822; Moncada 2012). Both species have apothecia with tomentose margins, but in the new species, the margins are also verrucous to rarely weakly crenate and often ciliate in the lower part, whereas in S. laciniata , only tomentose. In addition, in S. macrolobata , the apothecial discs are brown to chestnut-brown and in S. laciniata , orange to reddish ( Hooker 1822; Moncada 2012).

The new species forms a clade with Sticta borinquensis Merc.- Díaz & Lücking, S. densiphyllidiata Merc.- Díaz & Lücking, S. riparia and S. scabrosa (Fig. 1 ), although with low support. All four species produce abundant propagules in the form of phyllidia which are absent in the new species ( Mercado-Díaz et al. 2020; Moncada et al. 2021b). Sticta borinquensis and S. densiphyllidiata are epiphytic species known so far from Puerto-Rico ( Mercado-Díaz et al. 2020) and S. riparia is reported here as new to Bolivia (see below). Sticta scabrosa subsp. scabrosa was recently confirmed from Bolivia ( Ossowska et al. 2022b) and apothecia were observed in the Bolivian specimens for the first time.

Figures

Figure 1. Best-scoring Maximum Likelihood tree of the Sticta target clade containing the new species from Bolivia (red) and the species new to Bolivia and phylogenetically confirmed from Bolivia (blue), based on the fungal ITS barcoding marker. Supported clades are thickened. For complete tree with individual support values, see Suppl. material 2.

Figure 3. Morphology of Sticta macrolobata (holotype) A upper surface B lower surface C apothecia with verrucous to tomentose margins D lower tomentum with cyphellae E rhizines F section of apothecium. Scale bars: 1 mm (A-E); 100 μm (F).