Sticta kukwae Ossowska, Magain & Sérusiaux, 2025

Sticta kukwae Ossowska, Magain & Sérusiaux sp. nov.

Fig. 3 View Figure 3

Diagnosis.

Differing from S. weigelii in lobes with sinuous margins, in the presence of marginal phyllidia, and the scarce, submarginal apothecia, as well as the primary tomentum being light brown to brown, dense, and sparse towards the margins.

Type.

Bolivia. • Dept. La Paz; Prov. Franz Tamayo, Área Natural de Manejo Integrado Nacional APOLOBAMBA, between la Cumbre and Pelechuco, close to Aguas Blancas , 14°49'12"S, 69°07'05"W, elev. 4070 m, open high Andean vegetation, Altoandino, saxicolous, 15 Nov. 2014, M. Kukwa 14729 a (holotype UGDA L-65224 , isotype LPB) GoogleMaps .

Description.

Stipe absent. Thallus suborbicular to irregular, up to 10 cm diam., moderately branched, with 3–5 branches per 5 cm radius, branching anisotomous to polytomous; lobes ligulate to flabellate, undulate, with their apices rounded, revolute, and their margins sinuous, not thickened; lobe internodes 5–9 mm long, 4–9 mm broad; thallus coriaceous. Upper surface smooth to shallowly pitted, yellowish brown to brown when dry, shiny; surface glabrous, few lobes with papillae but without maculae; true cilia absent. Only two apothecia found, submarginal, with slightly pronounced invagination on lower side, up to 1.5 mm diam.; disc brown; margin smooth, brown to dark brown. Phyllidia present, marginal and laminal, simple, branched, palmate to corymbose, vertical to obliquely arranged, globular at first, then spatulate to squamiform, usually darker than the thallus. Lower surface uneven, light brown; primary tomentum dense and thick to the margin, sometimes absent at the very edge, fasciculate to spongy, soft, white to brown, sometimes brown with brighter apices; secondary tomentum present, arachnoid. Rhizines present, only on few lobes, whitish to brown, simple to branched, densely distributed. Cyphellae 1–20 per cm 2 towards the thallus center and 1–20 per cm 2 towards the margin, dispersed, rounded to irregular, urceolate with wide pore, erumpent to sessile, remaining below the level of the primary tomentum, with the margin elevated and involute, white to beige colored, with tomentum; pore up to 0.5 mm diam.; basal membrane scabrid, white, K + yellowish, C –, KC –, P –. Medulla compact, white, K –, C –, KC –, P –. No substances detected by TLC.

Upper cortex paraplectenchymatous, up to 65 μm thick, uniform, consisting of up to 7 cell layers with cells 5–10 μm diam., their walls up to 1.5 μm thick. Photobiont layer up to 130 μm thick, its cells up to 15 μm diam. Medulla up to 120 μm thick, its hyphae 4 μm broad, without crystals. Lower cortex paraplectenchymatous, up to 60 thick, with 7 cell layers; cells up to 10 μm diam., their walls up to 2.5 μm thick. Lower primary tomentum up to 400 μm long, with cells resembling secondary tomentum and probably representing thalloconidia, simple or in fascicles formed of up to 20 hyphae, hyphae simple. Lower secondary tomentum 70 mm long, simple to branched, moniliform. Cyphellae cavity up to 150 μm deep; cells of basal membrane without or with single papillae. Apothecia lecanorine (with algal layer below cortex), up to 250 μm high, without distinct stipe; excipulum 150 μm broad, without projecting hairs. Hymenium up to 75 μm high; epihymenium 5 μm high, orange-brown with gelatinous upper layer. Asci immature. Ascospores not observed.

Habitat and distribution.

Sticta kukwae is known from Bolivia and Peru. In Bolivia, it was found saxicolous and was collected at a single locality in the Área Natural de Manejo Integrado Nacional Apolobamba in the Department La Paz, at an altitude of 4070 m. In Peru, it was also saxicolous and found in four localities in Puno, in a vegetation type of Roquedal, Matorral de Puna, at an altitude of 3850 m.

Etymology.

Named in honor of the lichenologist Martin Kukwa for his contribution to the taxonomy of lichens and lichenicolous fungi in Bolivia.

Additional material examined.

Peru. • Puno - Carabaya, Ollachea - Macusani (20 km of Macusani ), in a vegetation type of Roquedal, Matorral de Puna, on rocks on the ground / close to the ground, 23 May 2012, N. Magain ( LG 3225 , LG 3227 , LG 3221 & LG 3223 ) .

Notes.

Sticta kukwae is another species in the S. weigelii morphodeme, along with the recently described S. andina B. Moncada, Lücking & Sérus. , S. scabrosa , and S. waikamoi Moncada & Lücking. It differs from these species in the type of vegetative propagules and the presence of lobes with strongly sinuous margins, which have not been observed in the other species. Sticta weigelii s. str. and S. waikamoi produce isidia, and S. andina has isidia and phyllidia. Sticta scabrosa , as S. kukwae , produces phyllidia, but in this taxon, they are the same color as the thallus, whereas in the new species, they are blackish-brown. Both species can produce sparse apothecia, but in S. kukwae their margins are crenate and dark brown, whereas in S. scabrosa they are entire to very rarely shallowly crenate and in the same color as the thallus ( Moncada et al. 2021 b; Ossowska et al. 2022 b). Sticta andina may also have apothecia, but they are abundant and with verrucose to crenate margins ( Moncada et al. 2021 a, b; Ossowska et al. 2022 b). Another difference is found in the color of the lower surface, as S. andina has dark lower surface, in S. scabrosa it is yellow-brown, while in S. weigelii the color ranges from beige to dark brown, and in S. waikamoi it is dark brown ( Moncada et al. 2020, 2021 a, b; Ossowska et al. 2022 b). The newly described species has a light brown lower surface. Sticta andina and S. scabrosa have a wide distribution ( Moncada et al. 2021 a, b; Kaasalainen et al. 2023). In contrast, S. weigelii was previously assumed to be widespread ( Galloway 1994, 1997, 2006). However, recent research has shown that its distribution is probably limited to the Neotropics ( Moncada et al. 2021 b; Mercado-Díaz et al. 2023). All three taxa are also known from Bolivia ( Ossowska 2021; Ossowska et al. 2022 b). Sticta waikamoi is known from the Hawaiian islands ( Moncada et al. 2020, 2021 a). Only S. weigelii has been reported from Peru ( Ramos 2014), but without molecular evidence.

In the phylogenetic tree (Fig. 1 View Figure 1 ), the new species is closely related to S. umbilicariiformis . However, it has many marginal pustules, which can sometimes make it appear sorediate; thalli is often quite large, and lobes are thick with wavy to foveolate margins. Additionally, the lower surface is cream-colored to brown and thickly tomentose. Sticta umbilicariiformis has been documented in East Africa, with a high probability of its occurrence in other regions as well ( Magain and Sérusiaux 2015; Kaasalainen et al. 2023).

The presence of lobes with sinuous margins is also a characteristic feature in the recently distinguished S. monlueckiorum Ossowska, Flakus & Rodr. - Flakus from Bolivia. In S. monlueckiorum , the thallus is larger (up to 10 cm) and moderately branched, while the apothecia are laminal with hirsute margins and without vegetative propagules ( Crous et al. 2023), whereas S. flakusiorum has a hirsute upper surface with abundant, submarginal apothecia and without vegetative propagules. All three taxa differ also in the color of the lower surface and the density of the cyphellae. In S. monlueckiorum , the lower surface is beige to yellowish, and the cyphellae have a density of 41–60 per cm 2 towards the center and more than 100 towards the margins ( Crous et al. 2023). In S. flakusiorum , the lower surface is brown, and the cyphellae are 1–20 per cm 2 towards the center and 41–60 per cm 2 towards the margins, and in S. kukwae , 1–20 per cm 2 towards the thallus center and margins.

The hyphae of primary tomentum of Sticta kukwae produce peculiar structures that resemble budding conidia forming chains. Similar structures were found in the isidiate S. atlantica Magain & Sérus. , S. fuliginoides Magain & Sérus. , and S. fuliginosa by Magain and Sérusiaux (2015), who stated in the case of S. fuliginosa they can act as conidia. These cells in the mentioned species are very similar to cells of secondary tomentum in several Sticta species, and possibly both can play a role of conidia. Such spores thus can be named thalloconidia, which are on the other hand known mainly in several species of the genus Umbilicaria Hoffm. ( Hestmark 1990, 1991, 1992), but also in some crustose lichens (e. g., Miriquidica nephaea (Sommerf.) P. F. Cannon , Protoparmelia leproloma (R. Sant.) Rambold & Poelt , Protoparmeliopsis peltata (DC.) Arup, Zhao Xin & Lumbsch , Rhizoplaca melanophthalma (DC.) Leuckert & Poelt , Sporastatia karakorina (Obermayer & Poelt) Davydov & Yakovch. ) ( Poelt and Obermayer 1990). However, the ultrastructural study of their development must be performed prior to the final change in the conception of their role.