Erichansenia S. Y. Kondr., Kärnefelt et A. Thell, gen. nov.
MycoBank number: MB 834210; Index Fungorum number: IF 834210; Facesoffungi number: FoF 11740
Similar to Shackletonia, but differs in having better developed epilithic thallus, in having mostly completely black apothecia with a dark greenish blue outer exciple, in having Lecidea green pigment in the cortex of thallus and exciple, as well as in distribution in both northern and southern hemispheres.
Type species: Erichansenia epithallina (Lynge) S. Y. Kondr., Kärnefelt et A. Thell
Thallus crustose, epilithic or lichenicolous on epilithic lichens, rather continuous, reduced to tiny fragments surrounding apothecia. Surface com- pletely rugose, minute to deeply cracked or rimose, grey to dirty greyish, of- ten blackish within the cracks, in some areas pale brownish tinged, epruinose. Cortex paraplectenchymatous. Epicortex hyaline or sometimes brownish, composed of necrotic fungal tissue. Vegetative diaspores are absent.
Apothecia lecideine, completely black (but dark reddish orange discs in young apothecia in Erichansenia sauronii), epruinose, with a dark green- ish blue prosoplectenchymatous outer exciple. Hymenium hyaline to faintly blue. Epithecium dark greenish blue to blackish with dispersed deep-orange
anthraquinone granules. Hypothecium hyaline to brownish. Paraphyses sim- ple to sparingly branched at the top, slightly or hardly widening towards the apices, with blue-tinged cell walls. Asci clavate, Teloschistes type, with eight spores. Ascospores polardiblastic, ellipsoid. Conidiomata not known.
Chemistry: Cortical layer of thallus K–, C–, KC–, I/KI+ violet to deep blue, 10% N–, cN+ strongly pinkish (Lecidea green, sensu Wetmore 1994, 1996). Epicortex I+ violet. Medulla I+ violet or I–; outer part of the exciple I/KI+ vio- let, cN+ strongly pinkish (Lecidea green). Epithecium K+ faintly violet, C–, cN+ strongly pinkish (Lecidea green).
Ecology: Growing on siliceous rocks (large granite rocks, especially in cracks and small crevices); or lichenicolous on various crusts (rarely on foli- ose lichens): Dimelaena oreina (Ach.) Norman, Pleopsidium oxytonum (Ach.) Ra- benh., Protoparmeliopsis muralis (Schreb.) M. Choisy, P. peltata (Ramond) Arup, Zhao Xin et Lumbsch and Sedelnikovaea subdiscrepans (Nyl.) S. Y. Kondr., L. Lőkös et Farkas, as well as Aspicilia sp., Buellia sp., Montanelia sp., Protopar- melia sp., Rhizocarpon sp.; at altitudes of 300–2,900 m a.s.l. in all ecological categories.
Etymology: The genus is named to honour the distinguished Danish li- chenologist Eric Steen Hansen (C, Denmark) to recognise his contribution on particularly the lichen diversity of Greenland, and to lichenology in general.
Distribution: Erichansenia species occur worldwide, E. cryodesertorum and E. sauronii are known from scattered localities of continental Antarctica, while E. epithallina from the northern hemisphere.
Taxonomic notes: In original paper where the genus Shackletonia Søch- ting, Frödén et Arup was described (Arup et al. 2013) ‘Shackletonia’ sauronii (Søchting et Øvstedal) Søchting, Frödén et Arup and the type species Shackle- tonia hertelii (Søchting, Øvstedal et Sancho) Søchting, Frödén et Arup were po- sitioned in different branches without further discussion on the polyphyletic habit of the genus Shakletonia.
Garrido-Benavent with colleagues (Garrido-Benavent et al. 2016) have stressed that “addition of the next Shackletonia species, i.e. ‘Shackletonia’ cryo- desertorum illustrated the bigger differences of Shackletonia s. str. branch and the ‘Shackletonia’ sauronii branch, including this species and ‘Shakletonia’ cryo- desertorum”. However, no taxonomic conclusions were made.
Vondrák et al. (2019) showed a close position of Shackeltonia and ‘Calo- placa’ epithallina using nrITS phylogeny only. According to them ‘Caloplaca’ epithallina was positioned within the ‘Shackletonia’ s. lat. subclade, but in the outermost position to all species of the genus Shackletonia. ‘Caloplaca’ epithal- lina was also mentioned as ‘Shackletonia’ epithallina. However, no new combi- nation was proposed.
A combined phylogeny of the Teloschistaceae provided within this study shows that the three taxa, i.e. Erichansenia cryodesertorum, E. epithallina and E. sauronii, constitute a separate monophyletic branch in sister position to the Shackletonia s. str. branch (i.e. the Shackletonia hertelii branch), while the former branch is segregated as separate genus Erichansenia.
According to our phylogenetic analysis the genera Erichansenia and Shackletonia are positioned in the outermost position to the other genera of the Xanthorioideae, similarly as in phylogenetic trees published by Arup et al. (2013), Søchting et al. (2014b), and Garrido-Benavent et al. (2016). The genus Shackletonia, a genus comprising lichen-forming, lichenicolous, and muscicol- ous species, is known from Antarctica and southern Patagonia (Arup et al. 2013). Shackletonia is distinguished from other Xanthorioideae groups by its unique chemistry, producing 5- and 7-chloroemodin and their derivatives.
In the key to Shackletonia (s. lat.) species Garrido-Benavent et al. (2016) included also one additional species ‘Caloplaca’ psoromatis Olech et Søchting. It could be a member of the genus Shackletonia, however molecular data are still missing.
The genus Erichansenia is similar to Shackletonia, but differs in having bet- ter developed epilithic thallus (it grows on naked granitic rocks vs. licheni- colous and muscicolous), in having mostly completely black apothecia, with a dark greenish blue outer exciple (vs. the initial dark orange colour of the apothecial disc), in having Lecidea green pigment in the cortex of thallus and exciple, as well as in distribution in both northern and southern hemispheres. Species of the genera Huea C. W. Dodge et G. E. Baker and Pyrenodesmia A. Massal. also show blackish or black apothecia. Huea species differ from Erichansenia by showing different chemical reactions and epithecium lacking anthraquinones, whereas Pyrenodesmia species have a different thallus mor- phology, pigmentation, chemosyndrome type, and microhabitat preferences. The genus Erichansenia is similar to Blastenia A. Massal. of the subfamily Caloplacoideae in having dark brown to rusty brown or rusty reddish own margin or/and disk of apothecia, but differs in having mostly indistinct or badly developed thallus, in having mostly wider variation of ascospores and ascospore septum measurements and in having Lecidea green pigment in the cortex of thallus and exciple as well as in positioning in the subfamily Xantho-rioideae of the Teloschistaceae.