Atrophysma cyanomelanos T. Sprib. sp. nov.
MycoBank number: MB 830091;Index Fungorum number: IF 830091; Facesoffungi number: FoF 13338;
A cyanolichen with minutely coralloid, finger-like lobes over a black hypothallus, black apothecia, internally with a black pigment, revers- ibly HNO3+ mauve, KOH+ remaining blackish but weakly greenish tinged, and simple ascospores, 11.0–16.0 × 7.1–8.1 μm, frequently with a warted gelatinous epispore.
Type: USA, Alaska, Hoonah-Angoon Census Area, Glacier Bay National Park, Excursion Ridge, ridgetop, 58.46503°N, 135.55757°W, 903 m, saxicolous on argillite slabs on alpine ridgetop covered by deep snow much of the year, 1 August 2012, Spribille 39425 (MSC— holotype; NY—isotype).(Fig. 11)
Thallus a sprawling crust up to 7 cm diam., becoming confluent with adjacent thalli, olivaceous brown, consisting of minute coralloid fingers 70–150 μm diam.; hypothallus present as a black base to the coralloid fingers, but not extending beyond the perimeter of the main thallus, coloured with the same pigment as the apothecia (see below); individual lobes consisting of tightly packed Nostoc-like cyanobacterial cells with fungal hyphae sheathed in a gelatinous cortex-like layer, a cellular cortex lacking.
Ascomata apothecia, round, sometimes flexuose, single or grouped, (0.25–)0.5–0.6(–1.3) mm diam., often absent; disc flat to more often convex, jet black, matt, sometimes hollowed out (herbivory?) leaving concave shells; proper margin prominent, receding with age but not disappearing, matt. Excipulum 60–90 μm wide laterally, to 40 μm wide basally, composed of radiating, anastomosing hyphae that widen towards the tips, up to 8–9 μm diam. with lumina to 3–5 μm, streaked with black pigments externally, POL+ crystals not seen. Hymenium (60–)70–90 μm tall, hazy reddish brown, I+ wine red before KOH treatment, upper- most part (‘epihymenium’) lacking crystals, heavily black- pigmented, the pigment reversibly HNO3+ mauve, KOH+ remaining blackish but weakly greenish tinged, similar to the ascomatal pigments in Farnoldia and the hypothallus pigments in Placynthium; paraphyses mostly simple, 2–4 μm wide at midpoint, not widened apically, moniliform. Hypothecium to 200 μm thick, hyaline or light reddish brown, grading in the lowermost 50–150 μm to deep brown, I+ wine red. Asci 8-spored, widely flask-shaped, lightly amyloid externally, I− internally, lacking an amyloid apical tube or tholus; ascospores simple, broadly ellipsoid, (10–)11.0–16.0 (–19) × (5.5–)7.1–8.1(–9.5) μm, frequently with a warted gelatinous epispore (n = 60, from six specimens). Pycnidia not observed.
Chemistry. No secondary substances detected.
Etymology. From kyanos (blue) and melas (black), referring to the characteristic contrasting colours of the ascomata and thallus upon close examination.
Habitat. On rock, apparently preferring weakly calcareous rock (in GLBA, argillite) in subalpine and alpine habitats.
Notes. We first encountered this species working in KLGO and tentatively assigned it, as a ‘known unknown’, to the genus Santessoniella Henssen (Spribille et al. 2010, as Santessoniella sp. 24535). The GLBA material is much richer and gave us a broader basis for morphological as well as DNA analysis but placing the new species into an existing genus proved impossible. Ekman et al. (2014) showed that Santessoniella as circumscribed by Henssen (1997) is polyphyletic and its characteristic thallus morphology evolved independently. In addition, the type of the genus, S. polychidioides (Zahlbr.) Henssen, has been recovered within Psoroma Ach. ex Michx. with moderate support, suggesting that the former genus will be lost to synonymy. We also suspected a relationship to Leciophysma Th. Fr., but species of that genus have a distinct I + apical tube in the ascus (such as in L. saximontana (T. Sprib. et al.) P. M. Jørg. et al., a species initially described in Santessoniella but later placed in Leciophysma; Spribille et al. 2007; Ekman et al. 2014). We also know of no species of Pannariaceae with the black pigments of this species, which recall those in Placynthiaceae. We considered a possible placement in the latter family but no Placynthiaceae are known to have simple ascospores. Multilocus DNA sampling from the apothecia of the new species placed it in the Pannariaceae (Fig. 9). A continued discussion of species formerly placed in Santessoniella can be found under the treatment of Fuscopannaria dillmaniae later in this paper.
Fig. 9. Majority-rule consensus tree of the suborder Collematineae (order Peltigerales) showing placement (in bold) of four new species and a ‘known unknown’ based on four loci. Dots and dashes to the right of tip names indicate presence and absence of loci, respectively, in the following order: ITS, 28S, mtSSU, Mcm7. Values indicate percent bootstrap support. Alphanumeric codes in brackets are identifiers unique to this study. Voucher information and GenBank Accession num- bers are outlined in Table 1 and Supplementary Material Table S3 (available online).
Fig. 11. Atrophysma cyanomelanos (holotype). A & B, habit; C, habit with SEM; D, broken thallus lobe with SEM; E, broken thallus lobe in brightfield microscopy; F, ascoma section (composite image); G, ascus stained in Lugol’s solution. Scales: A = 1 mm; B & C = 0.5 mm; D & F = 50 μm; E & G = 10 μm.