Didymocyrtis azorica Etayo & Pino-Bodas, 2021

Etayo, J. & Pino-Bodas, R., 2021, Notes on lichenicolous Pleosporales, with two new species, Didymocyrtis azorica and Pseudopyrenidium epipertusariae (Phaeosphaeriaceae), Phytotaxa 494 (1), pp. 75-88 : 84-85

Didymocyrtis azorica Etayo & Pino-Bodas , sp. nov. ( Fig 4 )

Mycobank MB 838957

Diagnosis: Similar to Didymocyrtis micropunctum but this species has completely immersed ascomata, larger spores, 10.5–15 x 4–6 µm, with verruculose, not striate ornamentation. Furthermore, the type host of D. micropunctum is Parmotrema .

Type:— PORTUGAL. The Azores, Terceira, Reserva Nacional Serra de Santa Barbara , volcanic domes of Misterios Negros , Lagoa do Negro , on thallus of Hypotrachyna rockii (Zahlbr.) Hale on mossy branches of laurisilva trees, 600–650 m, 38º44’01’’N, 27º17’05’’W, 22 July 2017, J. Etayo 30968 (PO-holotypus, hb. Etayo-isotypus) .

Ascomata perithecioid, black, immersed, subglobose, 90–120 µm diam., grouped but not confluent, mature mixed or not with younger ones or bad developed ones much more abundant. Ascomatal wall formed by thin, branched hyphae with thin wall, brown color, K+ greenish black, 1.5–2 µm thick surrounded by an extracellular pigment forming clusters. Hymenium I-, KI-. Paraphyses abundant, very thin, near 1 µm wide, branched-anastomosed, not capitated. Asci cylindrical, 8-spored, widened apically, KI-; epiplasm I, KI+ orange color, 58–73 × 6.5–8 µm. Ascospores brown, 1-septate, not constricted in the septum, with obtuse apex or, more frequently, slightly papillate in the apex, with a large oil guttule by cell, rarely two, with ornamented surface, striate around parallely to the long axe, (7.5–)8–9(–11) × 4.5–5.5 µm, without sheath when young.

Host and distribution: It is known only from Terceira where it has been collected in two localities on Hypotrachyna rockii .

Discussion: The most similar described species is D. micropunctum Etayo (2017: 176) , reported on Parmotrema from Ecuador. This has larger spores 10.5–15 × 4–6 μm with not striate but verruculose surface. Its habitus is also different, D. micropunctum has perithecia completely sunken in the host thallus and they are difficult to see, while in D. azorica perithecia are more visible and intermixed with young or poorly developed ones. Furthermore, D. azorica has ascomata covered by thin and brown hyphae, K+ greenish black. Polycoccum montis-wilhelmii Diederich in Aptroot et. al. (1997: 141), whose type was also collected on Hypotrachyna , is distinguished by its shorter and wider asci, 47–60 × 12–15 µm and larger ascospores 14.5–16 × 6.5–7 µm, with verruculose surface and with a thin sheath amongst other differences. Finally, Didymocyrtis melanelixiae has also been recorded on Hypotrachyna from UK (ERTZ et al. 2015). This species differs from D. azorica in its larger perithecia (200–250 µm diam.), larger asci (70–100 x 7.5–10.5 µm and larger spores (11.5–15 x 4–5.5 µm) that are (1–)2(–3) septate with verruculose ornamentation (ERTZ et al. 2015).

Additional studied specimens: PORTUGAL. The Azores: Terceira, Malha Grande, trail Rocha do Chambre, cresta ventosa, on Hypotrachyna rockii on big Erica azorica , 510 m, 38º45’02’’N, 27º15’08’’W, 24 July 2017, J. Etayo 31009 (hb. Etayo).

Figures

FIGURE 4. Didymocyrtis azorica sp. nov. (holotypus). A, B, habitus with immersed perithecia on Hypotrachyna thallus mixed with other smaller structures less developed. C, ascus and paraphyses (KI). D, E, H, asci (water). F, G, ascospores ornamented with striation subparallel with the large sporal axe. Scales A, B = 100 µm; C, E, F, G, H = 10 µm; D = 50 µm.