Sticta pseudoimpressula Ossowska, Kukwa, B. Moncada & Luecking, 2022

Ossowska, Emilia Anna, Moncada, Bibiana, Kukwa, Martin, Flakus, Adam, Rodriguez-Flakus, Pamela, Olszewska, Sandra & Luecking, Robert, 2022, New species of Sticta (lichenised Ascomycota, lobarioid Peltigeraceae) from Bolivia suggest a high level of endemism in the Central Andes, MycoKeys 92, pp. 131-160 : 131

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

Fig. 7

Diagnosis.

Differing from S. impressula in the presence of imbricately arranged and grouped apothecia with orange-yellow pruina along the margin of the disc, reacting K+ carmine-red and in the presence of a secondary tomentum.

Type.

Bolivia. Dept. La Paz; Prov. Franz Tamayo, Área Natural de Manejo Integrado Nacional Apolobamba, near Río Pelechuco, below Pelechuco close to new road to Apolo , 14°46'39"S, 69°00'35"W, elev. 2250 m, lower montane Yungas cloud forest, corticolous, 16 Nov 2014, M. Kukwa 14750 (holotype UGDA, isotype LPB) .

Description.

Primary photobiont cyanobacterial ( Nostoc ). Stipe absent. Thallus irregular to suborbicular, up to 10 cm diam., moderately branched, with 3-5 branches per 5 cm radius, branching polytomous; lobes laciniate to flabellate, adjacent, plane, with their apices orbicular and revolute to involute and their margins entire to crenate, not thickened; lobe internodes (4-)7-10(-15) mm long, (4-)7-9(-15) mm broad; thallus coriaceous. Upper surface pitted to scrobiculate to rugose towards the centre, yellowish-brown with darker apices in the herbarium, with marginal line in the same colour, shiny; surface glabrous, without papillae and pruina, without maculae; marginal cilia present, abundant, fasciculate, light brown to dark brown, about 0.5 mm. Apothecia abundant, laminal, dispersed, often imbricately arranged and grouped, subpedicellated, with pronounced invagination on lower side, up to 3.5 mm diam.; disc red-brown to brown, sometimes greenish-yellow due to the presence of pruina, shiny; margin entire to crenate and hirsute, with white hairs and orange-yellow pruina. Vegetative propagules absent. Lower surface uneven, beige to dark brown towards the centre; primary tomentum dense to the margin, thick (long), spongy, soft, grey-brown to black with paler tips; secondary tomentum present, but sparse, pubescent, up to 30 μm long. Rhizines sparse, black, up to 0.5 mm. Cyphellae 1-20 per cm2 towards the thallus centre and 41-60 per cm2 towards the margin, scattered, irregular, cupuliform to urceolate with wide pore, prominent, below the level of the primary tomentum, with the margin erect, cream to brown coloured, without or with tomentum in the lower half; pore (0.5-)0.6-1.3(-2.5) mm diam.; basal membrane pruinose in the appearance, white to pale beige in older part of thallus; K- to K+ pale yellow, C-, KC-, Pd-. Medulla compact, beige-white, K+ yellow, C-, KC-, Pd-. Apothecia margin (ring around disc) and epihymenium K+ carmine-red. No substances detected by TLC, unidentified anthraquinone in apothecia.

Upper cortex paraplectenchymatous, 20-40 μm thick, consisting of 2-3 cell layers with cells 6-22 μm diam. (with smaller cells in outside parts of the cortex), their walls 1-2 μm thick and their lumina rounded to isodiametric, 5-21 μm diam. Photobiont layer 60-110 μm thick, its cells 7-18 μm diam. Medulla 30-100 μm thick, its hyphae 3-5 μm broad, without crystals. Lower cortex paraplectenchymatous, 25-40 μm thick, with 3-4 cell layers; cells 8-18 μm diam., their walls 2-4 μm thick. Hairs of lower primary tomentum up to 1000 μm long, in fascicles of more than 20, hyphae unbranched to rarely branched, septate with flexuous apices. Cyphella cavity 100-125 μm deep; cells of basal membrane loosely packed consisting of cells without papillae or very rarely one. Apothecia biatorine, up to 700 μm high, without distinct stipe; excipulum up to 125 μm broad, laterally with projecting hairs, in groups to rarely simple, up to 0.5 mm, 5-6 μm broad. Hymenium 80-110 μm high; epihymenium 20 μm high, orange, with pigment granules on the top, without gelatinous upper layer. Asci 6-8-spored, ascospores fusiform, 1-3-septate, 28-35 × 8.5-10 μm.

Habitat and distribution.

Sticta pseudoimpressula is an epiphytic species, found in Bolivia at one locality at an altitude of 2250 m in a lower montane Yungas forest in the Department La Paz.

Etymology.

The name refers to the similarity in morphology to Sticta impressula .

Additional material examined.

Bolivia. Dept. La Paz; Prov. Franz Tamayo, Área Natural de Manejo Integrado Nacional Apolobamba, near Río Pelechuco, below Pelechuco close to new road to Apolo , 14°46'39"S, 69°00'35"W, elev. 2250 m, lower montane Yungas cloud forest, corticolous, 16 Nov 2014, M. Kukwa 14752 (LPB, UGDA) .

Notes.

Sticta pseudoimpressula is similar to S. impressula (Nyl.) Zahlbr. Both species have a pitted to scrobiculate or rugose upper surface with abundant, laminal apothecia and the lobe margins with abundant, light brown cilia. The tomentum is dense to the margin in the latter ( Moncada 2012). However, the two species are not closely related phylogenetically (Fig. 1 ; Suppl. material 3: Fig. S1): Sticta impressula is clustered in a neighbouring clade with S. brevior B. Moncada & Lücking and S. isidiokunthii . In contrast, S. pseudoimpressula shares a common ancestor with S. bicellulata , S. peltigerella and S. sylvatica . The differences between S. pseudoimpressula and S. bicellulata are discussed under the latter.

The morphological features that distinguish S. pseudoimpressula from S. impressula are the moderately-branched thalli and the laciniate to flabellate lobes. The apothecia in S. pseudoimpressula are often imbricately arranged and grouped and produced orange-yellow pruina along the disc margins and reacts K+ carmine-red. A secondary tomentum is present in S. pseudoimpressula , but absent in S. impressula . In addition, the cyphellae in S. impressula are rounded to angular and urceolate with a wide pore, erumpent to suprasessile and the margins raised to involute. The latter taxon is widely distributed in Colombia, where it grows at elevations between 1500 and 3800 m ( Moncada 2012; Moncada et al. 2014b).

At first sight, S. pseudoimpressula can also be confused with S. brevior , but that taxon has smaller thalli with abundant apothecia, tomentose margins and the lower surface is undulating, creamy white to light brown ( Moncada 2012; Moncada et al. 2013b). Sticta brevior is known from Colombia ( Moncada et al. 2013b, 2014b).

Figures

Figure 1. Best-scoring Maximum Likelihood tree of the Sticta clades I-III containing the new species from Bolivia (blue) and Colombia (orange), based on the fungal ITS barcoding marker. Supported clades are thickened. For a complete tree with individual support values, see Suppl. material 3: Fig. S 1.

Figure 7. Morphology of Sticta pseudoimpressula (holotype) A, C upper surface with laminal apothecia B, D lower surface E group of imbricately arranged apothecia with hirsute margins F tomentum and cyphellae. Scale bars: 1 mm.