Fuscidea multispora Flakus, Kukwa & Rodr. Flakus, 2019

Guzow-Krzemińska, Beata, Flakus, Adam, Kosecka, Magdalena, Jabłońska, Agnieszka, Rodriguez-Flakus, Pamela & Kukwa, Martin, 2019, New species and records of lichens from Bolivia, Phytotaxa 397 (4), pp. 257-279 : 260-263

Fuscidea multispora Flakus, Kukwa & Rodr. Flakus sp. nov. Mycobank MB 830057. Figs 1 & 2

Diagnosis: Differs from Fuscidea lightfootii in having smaller ascospores, 16-spored asci, lack of soredia, different substrate preferences (foliicolous) and secondary chemistry (sekikaic acid).

Type:— BOLIVIA. DEPT. COCHABAMBA: Prov. Carrasco, Parque Nacional Carrasco, Meruvia close to Monte Punku, 17º35’06”S, 65º14’54”W, elev. 3283 m, Podocarpus and Polylepis forest, foliicolous on Podocarpus sp. , 26 Nov. 2014, A. Flakus 25608.1 (holotype KRAM!; isotype LPB!).

Thallus foliicolous, greyish-green to brownish, verruculose, not continuous to almost continuous, verrucae developing on dark prothallus or on thin thallus layer, thallus 3–6 mm in diam., verrucae irregular in shape, 100–200 mm in diam, 20–100 μm tall, covered by thin dark brown cortical layer, c. 5 μm thick, inside with small crystals ( K + dissolving); soralia lacking; prothallus usually evident, dark brown to black; photobiont chlorococcoid, cells 5–12 μm in. diam; ascomata apothecia, dark brown to black, scattered, sessile, sometimes constricted at the base, marginate, rounded in shape, 0.2–0.6 mm in diam; disc dark brown to black, matte, epruinose, flat to slightly concave; excipulum evident from the beginning, concolorous with the disc, 40–80 μm wide, colourless inside, not inspersed by crystals or oil droplets, I –, composed of radiating hyphae with lumina 1–3 μm wide, outer part strongly gelatinized and containing brown pigment; epihymenium dark brown pigmented, K + olive (greenish grey), N + first grey than orange-brown, 5–10 μm thick; hymenium colourless to brown in the upper part (with less amount of the same pigment as in epithecium), not inspersed by oil droplets, 60–70(–80) μm high, strongly agglutinated, I + blue, K / I + blue, strongly lax after treatment by K; paraphyses colourless, rather branched at the top, composed of hyphae with lumina 1–1.5 μm wide, strongly thickened (2–4 μm wide) apically, with pigmented caps; subhymenium colourless, c. 10–15 μm high; hypothecium colourless to brownish in lower part, inspersed by clusters of crystals (size 3–15 μm in diam.), 30–50 μm high; asci 16-spored, clavate, K / I + blue at the top, Fuscidea - type (according to Hafellner 1984), 40–60 × 10–15 μm; ascospores colourless, simple, ellipsoid to bacillar, usually constricted in the middle or slightly curved, with 2 large guttules, with rather thick walls (c. 0.5 μm thick), without epispore, frequently with indistinct pseudosepta, (6–)7–8.5(–9) × 3.5–4.5 μm (n=30); conidiomata not seen.

Chemistry: Sekikaic acid by TLC.

Etymology: The name refers to the multispored asci.

Distribution and habitat: The species is known only from the type locality in the Andean forest dominated by Podocarpus and Polylepis trees.

Notes: The new species is characterized by dark brown to black lecideoid apothecia, greenish-grey to brownish and verrucose thallus, distinct dark prothallus, 16-spored asci, non-septate, usually constricted in the middle, hyaline ascospores and the presence of sekikaic acid. The genus Fuscidea V. Wirth & Vězda consists mainly of saxicolous and corticolous lichens ( Wirth & Vězda 1972; Kantvilas 2001; Fryday 2008; Zahradníková et al. 2017), but so far only F. fulva (Malme) Kalb was known as foliicolous; this is a rare lichen known only from the Atlantic rain forest in southern Brazil, but clearly differs from F. multispora by larger ascospores (10–15 × 5–7 μm) and 8-spored asci ( Lücking 2008).

The new species, due to its lecideoid apothecia and 16-spored asci, does not fully fit any genus in the Fuscideaceae Hafellner ( Umbilicariales J. C. Wei & Q. M. Zhou ) ( Hafellner 1984; Kantvilas 2001; Miadlikowska et al. 2006; Bylin et al. 2007; Zahradníková et al. 2017), and without molecular data it would be difficult to assign it properly at the genus level. As currently circumscribed, Fuscidea taxa develop lecideoid apothecia (very rarely incomplete thin thalline margin can be developed in some species) and has 8-spored asci. The 16-spored asci of F. multispora make the new species similar to Maronea A. Massal., which is characterized by lecanoroid apothecia and multispored asci ( Magnusson 1925, 1934; Wirth & Vězda 1972; Kantvilas 2001; Fryday 2008). Similar taxonomic problem concerns M. afroalpina Brusse , described form South Africa (Drakensberg), which has lecideoid apothecia and multispored asci ( Brusse 1989). This species can be easily separated from Fuscidea multispora by its ecology (saxicolous substrate preference), white pruinose apothecia, and the asci producing more ascospores (± 100) ( Brusse 1989).

Despite morphological disparities, F. multispora is clearly placed in our phylogenetic analyses in the Fuscidea clade ( Fig. 2 ). In Maximum likelihood and Bayesian analyses the topologies of the trees were very similar. A total of 23 sequences of Fuscidea were included in a final concatenated alignment of 2220 bp length ( Fig. 2 ). The phylogeny shows that F. multispora is placed in a highly-supported clade ( BS 100%, PP 1) together with F. arboricola Coppins & Tønsberg and F. lightfootii (Sm.) Coppins & P. James. Those species can easily be separated from F. multispora by the different substrate preference (corticolous), the production of soredia, 8-spored asci, and the production of different lichen metabolites (divaricatic acid in F. lightfootii and fumarprotocetraric acid in F. arboricola ) ( Tønsberg 1992; Gilbert et al. 2009; Zahradníková et al. 2018).

The genus Fuscidea is poorly studied in the Neotropics. Recently a new corticolous species, F. tropica van den Boom & Kalb was described from mountain ranges in Brazil, Guatemala and Venezuela ( Boom et al. 2014). This species also contains sekikaic acid, but clearly differs from F. multispora in the thicker, rimose-areolate and warted thallus, 8-spored asci, larger (up to 1.4 mm in diam.) apothecia and longer ascospores [8.5–11(–12) μm long] ( Boom et al. 2014).

Calvelo and Liberatore (2002) reported F. cyathoides (Ach.) V. Wirth & Vězda and F. impolita (Müll. Arg.) Hertel from Argentina, and Aptroot (2002) F. kochiana (Hepp) V. Wirth & Vězda and F. lightfootii from Brazil. All those species differ from F. multispora in 8-spored asci. Additionally, F. cyathoides has larger apothecia (up to 1.4 mm in diam.), bean-shaped ascospores, produces fumarprotocetraric acid, and usually grows on rocks (rarely on tree bark), F. impolita is a saxicolous species with larger ascospores and contains divaricatic acid, and F. kochiana grows on rocks, develops emarginate apothecia immersed in a thick thallus and contains divaricatic acid ( Fryday 2000, 2008; Gilbert et al. 2009; Zahradníková et al. 2017); for differences from F. lightfootii see above.

Figures

FIGURE 1. Fuscidea multispora (holotype). A–C, habit showing black marginate apothecia, verruculose thalli and black prothallus (C); D, cross section of thallus verrucae showing photobiont cells and brown cortical layer (mounted in LPCB), E, cross section of apothecium showing brown pigment in epithecium and outer part of exciple and hypothecium inspersed by crystals (mounted in LPCB); F, cross section of apothecium showing exciple composed of radiately arranged hyphae and part of hymenium with capitate paraphyses (mounted in LPCB); G, Fuscidea-type asci with 16-ascospores (mounted in Lugol soluton); H, ascospores. Scales: A–C—250 μm; D—10 μm; E—50 μm; F—25 μm; G–H—10 μm.

FIGURE 2. Maximum likelihood phylogenetic tree of Fuscidea inferred from concatenated three loci data set (nucLSU, nucITS and mrSSU) within Fuscideaceae. High nodal support values are indicated by bold branches, including ML bootstrap values ≥ 75% and MCMC posterior probability ≥ 0.9. The newly described F. multispora is in bold and highlighted. Candellariella vitellina, Umbilicaria crustulosa and U. proboscidea were used as outgroup.