Enterographa ducouretiana Lebreton & Carriconde & Brouste & Lespagnol & Stenger & Sérusiaux & Ertz 2023, sp. nov.
Creators: name: Lebreton, Elise
name: Carriconde, Fabian
name: Brouste, Damien
name: Lespagnol, Antoine
name: Stenger, Pierrelouis
name: Sérusiaux, Emmanuël
name: Ertz, Damien
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Lecanoromycetes
Ostropales
Graphidaceae
Enterographa
Enterographa ducouretiana

description: Enterographa ducouretiana Lebreton & Ertz, sp. nov. MycoBank No.: MB849332
(Figs. 1 & 2)
Foliicolous Enterographa with lirelliform ascomata immersed in pseudostromata, a dark purple hypothecium, (3–)5-septate ascospores measuring (16–)20.5(–24) × (2.5–)2.9(–3.5) µm and PD+ yellow pseudostromata.
Type:— NEW CALEDONIA. Province Sud, Col de Mouirange, in rainforest patch surrounded by shrubland vegetation, called ‘maquis’, 22°12’9.216” S, 166°40’11.244” E, November 18, 2022, Lebreton 1787a (holotype: PC0779840; isotypes: LG11991-ETR00A, NOU, BR).
Thallus continuous, smooth, thin, c. 15–30 µm thick, pale yellowish green, sometimes with a whitish tinge, matt, esorediate. Photobiont trentepohlioid; cells elongated and irregular in outline, 7–11 × 3.5–9 µm, in irregular plates.
Ascomata immersed in pseudostromata covered by the thallus, distinctly elongate-lirellate, usually sparsely branched; disc dark brown to black in young and older ascomata (with a purplish tinge when fresh), slit-like, 0.12–0.9 mm long and 0.02–0.04 mm broad, epruinose; pseudostromata solitary, prominent, with ± gentle flanks not constricted at base, 0.23–1 × 0.18–0.35 mm, smooth, pale yellowish green with an orange tinge (more strongly pronounced in fresh material), or white where the thallus is abraded; in section white and incrusted with hyaline, tiny crystals that dissolve in K. Exciple indistinct, c. 3–5 µm wide, I-, KI-. Subhymenium very thin, c. 5 µm high, colorless, I-, KI-. Hypothecium 12–17 µm tall, dark purple, K+ becoming black. Hymenium 55–65 µm tall, colorless, clear, I+ orange-red, KI+ persistently dark blue; epihymenium poorly defined, hyaline, I+ orange-red, K-. Paraphysoids branchedanastomosing, c. 1 µm thick, slightly enlarged at their apex, c. 1.5 µm thick. Asci narrowly clavate, 54–59 × 12–13 µm (n = 3), KI- except for a KI+ blue, ring-shaped structure surrounding a tiny ocular chamber. Ascospores hyaline, narrowly fusiform, (3–)5-septate, (16–)20.5(–24) × (2.5–)2.9(–3.5) µm, with a 1.5–2 µm thick gelatinous sheath.
Pycnidia not observed.
Chemistry: thallus: K-, C-, PD-, UV-, but pseudostromata PD+ yellow (probably due to the presence of psoromic acid); thin-layer chromatography not performed.
Etymology: This new species is named after Emilie Ducouret due to her essential role in coordinating the fieldwork in New Caledonia that led to its discovery.
Distribution and habitat: Enterographa ducouretiana is known only from the type collection in rainforest near a creek.
Notes: The new species fits well in the genus Enterographa because of its trentepohlioid photobiont, ascomata with an inconspicuous exciple, branched paraphysoids, clavate asci with a KI+ blue ring structure in the tholus, and hyaline, narrowly fusiform, septate ascospores. The new species is unique within the genus by the presence of a dark purple hypothecium. It is also characterized by the continuous thallus with narrowly lirelliform ascomata that are immersed in PD+ yellow pseudostromata covered by the thallus, a dark brown to black hymenial disc, and (3–)5-septate ascospores. Enterographa membranacea P.M. McCarthy & Elix (2018:49) resembles E. ducouretiana in having simple to sparsely branched lirelliform ascomata that are immersed in PD+ yellow pseudostromata covered by a thallus layer and (5–)6- septate ascospores of 18–25 × 2–3 µm. It differs from E. ducouretiana in having larger pseudostromata (0.4–1.5(–2) × 0.4–0.8(–1) mm) with plate-like crystals of calcium oxalate. The hymenial disc are pale to medium brown and the hymenia are taller (65–85 µm). Unlike E. ducouretiana, it lacks a dark purple hypothecium and instead has a hyaline to pale yellowish-brown hypothecium, K- and 15–22(–25) µm thick. Enterographa membranacea also differs in having a corticolous habit, even though growing on the smooth trunk of a palm tree, a substrate with a texture similar to leaves. The photobiont cells are much broader (7–10 µm), solitary or in very short filaments and not arranged in plates (McCarthy & Elix 2018). Among the foliicolous species of Enterographa with a PD+ yellow thallus and somewhat similar ascospores, E. bartlettii Sérus. (1984:292) differs from the new species in having a thallus dispersed in patches, much shorter ascomata (0.15–0.3 mm) with a pale orange brown disc, a thalline margin densely filled with calcium oxalate crystals, an algiferous layer next to the excipulum and (6–)7-septate ascospores that are broader (3.5–5 µm); E. bella R. Sant. (1952:106) has a photobiont with cells arranged in radiating plates, a thallus dispersed in patches, a deep orange-brown hymenial disc and 7-septate ascospores that are longer (22–29 µm); E. foliicola Lücking & Matzer (1996:111) has a photobiont with cells arranged in radiating plates, ascomata slightly constricted below with oxalate crystals in the thalline margin and 7(–9)-septate ascospores that are broader (3.5–5 µm); E. multiseptata R. Sant. (1952:108), E. perez-higaredae Herrera-Campos & Lücking (2002:213) and E. vezdae Sparrius (2004:63) have longer ascospores with notably more septa (7, 7–10(–14), 7–9 septate, respectively; Sparrius 2004, Lücking 2008). All these species also differ from the new species by the absence of a dark purple hypothecium. Among the corticolous and saxicolous species of Enterographa, E. elixii Sparrius (2004:39) is somewhat similar to the new species in having ascomata immersed in well-defined pseudostromata and in having dark hymenial discs, but this lichen has notably rounded to short lirelliform ascomata, a thick thallus (100–300 µm) and 3-septate ascospores (Sparrius 2004).
description: Published as part of Lebreton, Elise, Carriconde, Fabian, Brouste, Damien, Lespagnol, Antoine, Stenger, Pierrelouis, Sérusiaux, Emmanuël & Ertz, Damien, 2023, Enterographa ducouretiana sp. nov. (lichenized Ascomycota, Roccellaceae), a new foliicolous species from New Caledonia, pp. 247-252 in Phytotaxa 609 (3) on pages 248-249, DOI: 10.11646/phytotaxa.609.3.8, http://zenodo.org/record/8281407