Malmidea attenboroughii Kukwa, Guzow-Krzemińska, Kosecka, Jabłońska & 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 : 266-269

Malmidea attenboroughii Kukwa, Guzow-Krzemińska, Kosecka, Jabłońska & Flakus sp. nov. MycoBank MB 830058.

Figs 4 & 5

Diagnosis: Differs from other Malmidea species in having minutely verrucose to granulose-isidiate thallus, verrucose margin containing internal medullary chambers, K+ orange yellow pigment present in thalline and excipular medulla, and ascospores measuring 12–16 × 7.5–9 μm.

Type:— BOLIVIA. DEPT. LA PAZ: Prov. Abel Iturralde, SE of Tumupasa , Jardin Botánico UMSA, 14°09’46”S, 67°52’02”W, alt. 400 m, semi-natural Preandean Amazon forest, roadside, corticolous, 24 May 2017, M. Kukwa 19645 (holotype UGDA!; isotype LPB) .

Thallus crustose, corticolous, continuous or cracked, minutely verrucose to granulose-isidiate (best seen in the transversal section), greenish-grey, dull, up to 200 μm thick, granules when discrete 50–125 μm diam.; medulla in thallus and excipular granules pale yellow, K + orange yellow; prothallus thin, white, fibrous; hypothallus visible in some cracked areas of the thallus, white; apothecia sessile, rounded to irregular, up to 1.0 mm diam.; disc plane, flesh-coloured to brown; excipulum thin, up to 55 μm broad, distinct, not prominent, smooth to verrucose due to the presence of internal medullary chambers ( granifera type), cream-coloured to dark grey-brown, in some apothecia darker around the discs, yellow in parts where the outer margin layer is abraded above medullary chambers containing yellow pigment, externally paraplectenchymatous with small cells, hyaline, but close to hymenium dark brown, with internal medullary chambers filled with more or less loosely arranged hyphae and pigment; hypothecium up to 50 μm high, brown, K –; epithecium pale orange-brown; hymenium up to 90 μm high, colourless; asci 8-spored; ascospores simple, broadly ellipsoidal, with evenly thickened walls, 12–16 × 7.5–9 μm. Photobiont chlorococcoid.

Chemistry: Traces of two unknown substances by TLC in Rf classes C 3 and C 5. Yellow pigment reacting K + yellow-orange in groups of crystals present in medulla of thallus and granules, and in medullary internal chambers of apothecial margin.

Etymology: The species is named after Sir David F. Attenborough, an English broadcaster and naturalist, for his major contributions to the popularization of knowledge about biodiversity and nature protection.

Distribution and habitat: Known only from the type locality in Preandean Amazon forest in Bolivia.

Notes: Due to its granulose-isidiate thallus this species is morphologically similar to Malmidea cineracea Breuss & Lücking , but the latter differs in its smooth and entire margin with inner part densely encrusted with yellowishbrown granules ( K + greenish-yellow), and yellow pigments in its thallus medulla ( K –) ( Breuss & Lücking 2015). Other species with similar isidiate thalli differ in having a white medulla (e.g. M. furfurosa (Tuck. ex Nyl.) Kalb & Lücking ), granular to coralloid isidia (e.g., M. perisidiata (Malme) Kalb & Lücking ) or different ascospores size (e.g., M. corallophora Aptroot & Schumm ) ( Kalb et al. 2011; Schumm & Aptroot 2012; Breuss & Lücking 2015).

Based on mrSSU dataset, M. attenboroughii belongs the Malmidea genus, being placed in a well-supported clade together with M. bakeri (Vain.) Kalb , Rivas Plata, M. chrysostigma (Vain.) Kalb , Rivas Plata & Lumbsch & Lumbsch and M. variabilis Kalb ( Fig. 5 ); however, the relationships within the group are poorly supported, probably due to very short mtSSU sequences available in GenBank (in most cases of 324 bp). All three species develop thalli which are never granulose-isidiate, but in addition they differ in other characters. Malmidea variabilis has a thallus with distinct and large verrucae, smaller ascospores (9–12 × 6–8 μm) and contains atranorin (absent in M. attenboroughii ). This species was known only from Asia ( Thailand) ( Kalb et al. 2011, Breuss & Lücking 2015). Malmidea bakeri has a densely verrucose thallus, dark brown apothecial discs and contains atranorin as a major secondary metabolite; similarly to M. variabilis , it is known from Asia ( Thailand) ( Kalb et al. 2011, Breuss & Lücking 2015). Malmidea chrysostigma has a densely verrucose thallus with a golden orange medulla that reacts K + blood red to red–violet, and its ascospores are longer ( Kalb et al. 2011, Breuss & Lücking 2015).

Two other species which have morphologically similar apothecia, M. granifera (Ach.) Kalb , Rivas Plata & Lumbsch and M. leucogranifera M. Cáceres & Lücking , have densely verrucose thalli (both species), dark brown to blackish apothecial disc ( M. granifera ) or orange-brown hypothecium and apothecia ( M. leucogranifera ) ( Cáceres 2007; Cáceres et al. 2012; Breuss & Lücking 2015).Another species with similar apothecial morphology and ascospore size is M. piperis (Spreng.) Kalb , Rivas Plata & Lumbsch, but that species has a compact excipulum of conglutinated, radiating hyphae ( piperis type) ( Cáceres 2007; Kalb et al. 2011, Breuss & Lücking 2015).

Several sorediate and isidiate, but sterile, specimens of Malmidea ( Fig. 5 ) were also sequenced. Those with a thallus producing pustules with a yellow medulla and punctiform to confluent soralia, and therefore similar to M. flavopustulosa (Cáceres & Lücking) Cáceres & Kalb , form two distinct clades ( M. aff. flavopustulosa 1 and 2). They are morphologically similar and cannot be separated from each other based on thallus characters, therefore, without apothecia it is impossible to refer the name M. flavopustulosa to one of these clades; furthermore, all those specimens contain atranorin, which was not reported by Cáceres (2007).

A sample named M. cf. polycampia is morphologically also similar to M. flavopustulosa but lacks a yellow pigment and is thus similar to M. polycampia (Tuck.) Kalb & Lücking , but without apothecia its identity, as also in the case of isidiate material tentatively referred to as M. perisidiata (Malme) Kalb & Lücking , remains unclear.

Additional material of Malmidea examined. Malmidea aff. flavopustulosa 1. BOLIVIA. Dept. La Paz: Prov. Abel Iturralde, N of Tumupasa, 14°07’42”S, 67°53’37”W, alt. 395 m, Preandean Amazon forest, roadside, corticolous, 22 May 2017, M. Kukwa 19764, 19765 & 19785 ( LPB, UGA); Dept. Santa Cruz: Prov. Ichilo, Parque Nacional y Área Natural de Manejo Integrado Amboró, Macuñucu, 17°43’38”S, 63°35’38”W, elev. 465 m, Chaceño-Amazon forest, corticolous, 12 May 2017, M. Kukwa 19309 & 19313 ( LPB, UGA). Malmidea aff. flavopustulosa 2. BOLIVIA. Dept. La Paz: Prov. Franz Tamayo, between Mapiri and Apollo, 14º52’22”S, 68º21’10”W, elev. 1750 m, remnants of forest near pasture, corticolous, 19 Nov. 2016, M. Kukwa 18999 & 19006 ( LPB, UGA). Malmidea cf. perisidiata . BOLIVIA. Dept. La Paz: Prov. Abel Iturralde, between Ixiamas and Tumupasa, Orilla de Cuñaca, 13°56’44”S, 68°02’07”W, elev. 330 m, natural Preandean Amazon forest, corticolous, 23 May 2017, M. Kukwa 19612 ( LPB, UGA). Malmidea cf. polycampia . BOLIVIA. Dept. La Paz: Prov. Franz Tamayo, between Mapiri and Apollo, 14º52’22”S, 68º21’10”W, elev. 1750 m, remnants of forest near pasture, corticolous, 19 Nov. 2016, M. Kukwa 19002 ( LPB, UGA). Malmidea sp. BOLIVIA. Dept. La Paz, Prov. Franz Tamayo, between Mapiri and Apollo, 14º38’51”S, 68º24’44”W, elev. 1520 m, remnants of forest on savanna, corticolous, 18 Nov. 2016, M. Kukwa 18858 ( LPB, UGA).

* Megalospora sulphurata Meyen var. nigricans (Müll. Arg.) Riddle

This variety has been reported from Argentina, Brazil, Jamaica, Mexico and Venezuela ( Sipman 1983; Marcano et al. 1996).

Material examined. BOLIVIA. Dept. Tarija: Prov. Burnet O’Connor, 60 km from Tarija, new road between Tarija and Entre Ríos, 21º28’52”S, 64º17’41”W, 1837 m, Boliviano-Tucumano forest with Podocarpus , corticolous, 28 July 2015, M. Kukwa 16929 ( LPB, UGDA).

Figures

FIGURE 4. Malmidea attenboroughii (holotype). A–B, habit showing apothecia with distinct verrucose margin and granulose-isidiate thalli; C–D, cross section of apothecium showing paraplectenchymatous exiple with one (C) and two (D) internal medullary chambers (creamy coloured and opaque areas). Scales: A–B—500 μm; C–D—50 μm.

FIGURE 5. Bayesian phylogenetic tree of Malmidea based on mrSSU data set. Posterior probabilities are shown above branches. Internal branches, considered strongly supported, are represented by thicker lines. The newly sequenced specimens are marked in bold and collecting numbers precede the species names. In case of sequences downloaded from GenBank accession numbers precede the species names. The newly described M. attenboroughii is highlighted. Savoronala madagascariensis and two species of Sprucidea were used as outgroup.